375 votes, 43 comments. 26M subscribers in the space community. Share &amp; discuss informative content on: * Astrophysics * Cosmology * Space…

r/space on Reddit: The Hubble Space Telescope has lost a majority of its gyroscopes

After completing a series of tests and carefully considering the options, NASA announced Tuesday work is underway to transition its Hubble Space Telescope to operate using only one gyroscope (gyro). While the telescope went into safe mode May 24, where it now remains until work is complete, ...

NASA to Change How It Points Hubble Space Telescope - NASA Science

To preserve the telescope, which has been operating in space for nearly three and a half decades, NASA announced Tuesday that it will reduce the Hubble&#x27;s operations such that it will function on just a single gyroscope. This will limit some scientific operations, and it will take longer to ...

The Hubble Space Telescope has lost a majority of its gyroscopes | Ars Technica

The spacecraft was outfitted with a Soft Capture Mechanism during the final Space Shuttle servicing mission in 2009. Once the Hubble finally reaches the end of its operational life, an uncrewed vehicle will dock with it to perform a controlled reentry.

Official: Hubble Telescope to transition to single-gyro mode • The Register

264 votes, 67 comments. 26M subscribers in the space community. Share &amp; discuss informative content on: * Astrophysics * Cosmology * Space…

r/space on Reddit: NASA rejects Hubble Space Telescope rescue mission, trims its science

Billionaire space tourist Jared Isaacman offered to fix NASA&#x27;s Hubble telescope. Officials are still unsure the benefits outweigh the risks.

NASA Slaps Down Billionaire's Plan to Fly Up and Fix Hubble Space Telescope

Failing hardware on NASA’s Hubble Space Telescope may lead to less science, officials say, but the space agency isn’t ready to pursue a private repair mission

NASA Rejects Hubble Space Telescope Rescue Mission and Trims Its Science | Scientific American

NASA is shifting the way the Hubble Space Telescope points. The change is a work-around for a piece of hardware that&#x27;s become intolerably glitchy. Officials say Hubble will continue to do &#x27;ground breaking science,&#x27; for about another decade.

Hubble will change how it points, but NASA says 'great science' will continue

NASA will extend the life of the Hubble Space Telescope by switching to a mode where the spacecraft operates on a single gyroscope.

Hubble goes to single-gyro operating mode as NASA passes on private servicing mission - SpaceNews

Hubble update if newsy

Hubble

hubble

Solana Projects Attract Investments as the Ecosystem Grows Before its January 28 Mainnet launch, , a decentralized finance (DeFi) application on the Solana network, has raised $10 million. Hubble was able to accomplish this considerable rise with the help of some of crypto’s most powerful and well-known figures. Marius Ciubotariu, the project lead at Hubble Protocol, in an exclusive interview with Hackernoon, Hubble Protocol discussed the advantages of the Solana ecosystem, such as its scalability, composability, and latency. Three Arrows / DeFiance Capital, , , , ParaFi, Jump Capital, , CMS, Spartan, DeFi Alliance, and Mechanism Capital were among the investors in Hubble’s funding rounds. Delphi Digital Digital Currency Group Crypto.com Capital Decentral Park Capital Hubble will use this funding to grow its workforce and DeFi products throughout 2022. Hubble will commence the first phase of its development on January 28, a zero-interest lending platform that will produce USDH, a censorship-resistant crypto-backed stablecoin. USDH is primed to become a “building block” for additional protocols on Solana, as stated in Decentral Park Capital’s investment thesis. The protocol aims to improve the future of DeFi and Web3 continually. Hubble’s native token, HBB, allows users to earn the bulk of the protocol’s fees by minting USDH. The revenue streams contributing to this fee-share may expand in the future. HBB will be available on three launchpads at the end of January: SolRazr, Solanium, and DAO Maker. As the ecosystem for Solana is still at its nascent stage, building the initial infrastructure such as a decentralized stablecoin to a novel borrowing marketplace and undercollateralized lending is the key to building DeFi primitives for the Solana ecosystem. These are essential components of the Web3 financial stack on the most well-known cryptocurrency infrastructure. Solana Eats the Market Share of Ethereum In a research note, informed clients that the Solana blockchain might become the “Visa of the digital asset ecosystem” since it focuses on scalability, cheap transaction costs, and simplicity of use. Due to the success of Solana as a high throughput blockchain, projects such as Hubble Protocol are building DeFi infrastructure on the blockchain. Bank of America Since its premiere in 2020, Solana has seen rapid acceptance and has settled more than 50 billion transactions and has more than $11 billion in total value locked, and has been used to mint more than 5.7 million non-fungible tokens (NFTs). For comparison, Visa, the payment processing giant, handled 164.7 billion transactions in the year ended September 30. According to the bank, Solana is designed for consumer use cases like micropayments and gaming. While Solana promotes scalability, a less decentralized and secure blockchain comes with trade-offs, as seen by multiple network performance concerns since its launch. Ethereum values decentralization and security above scalability, resulting in periods of network congestion and transaction fees that are often more than the value of the transaction being transmitted. According to Bank of America, Solana and other blockchains might eat into Ethereum’s market share over time and will begin to differentiate themselves via user acceptance and developer engagement. Catch all the breaking news, and Don’t forget to like the story!

Hubble Protocol, a DeFi project on Solana Raises $10 Million Led By Crypto.com Capital, DCG and CMS 

Everything You Need to Know Before Building on the Stellar Blockchain

This paper is available on arxiv under CC 4.0 license.
Authors:
(1) Rikpratik Sengupta, Department of Physics, Aliah University, Kolkata 700 160, West Bengal, India (E-mail addresses: rikpratik.sengupta@gmail.com(RS)) Table of Links Abstract and Intro
The cosmological model
Discussion
Acknowledgments
References Abstract Keywords: oscillating universe, braneworld, bounce, turnaround, phantom. 1. Introduction The standard big bang model of cosmology is plagued by an initial singularity (at time t = 0), where the Friedmann equations describing the time evolution of the universe fails to render a plausible physical description of the space-time dynamics due to the diverging Hubble parameter H, which is a consequence of the infinitely large energy density prevailing in the very early universe. The scalar curvature R also diverges, implying that the initial singularity is a curvature singularity of the Ricci type, which are characterized by diverging energy densities. As shown in their famous singularity theorems by Hawking and Penrose, the initial big bang singularity cannot be avoided in a general relativistic (GR) setup provided the energy conditions are obeyed by matter filling up the universe[4, 5]. One of the key problems of the standard inflationary cosmology, besidies the ambiguity regarding the nature of the inflaton field is that, within the GR framework, inflation can not be past eternal[6]. So, if the inflation is preceeded by a radiation dominated phase, then the origin of the universe is singular. However, today many cosmologists are unhappy about the initial singularity and consider it to be a limitation of GR to describe space-times involving very large energy densities. If there is no big bang, then the possibilities are that the universe either experiences a quantum creation where there is a quantum mechanical tunelling into an inflationary phase, or it may be that the universe existed for an eternally long time in a quasi static state followed by an emergent inflationary phase, or there is a non-singular bounce replacing the singular big bang prior to which the universe contracts and following which the universe expands. In the context of GR, the emergent and bouncing scenarios can be realised effectively only for a spatially closed universe (k = 1). A fully consistent treatment of the first possibility considering quantum creation will most probably require a quantum gravity (QG) treatment. However, there is no fully understood and developed QG theory at the moment and the two most accepted theories being worked on in this context are M-theory[7] involving extra dimensions and Loop Quantum Gravity (LQG)[8]. M- theory requires eleven space-time dimension for its quantum consistency while LQG quantizes space-time itself in the usual four dimensions. Effective theories from both the scenarios have become popular in recent times in the form of the extra dimensional braneworld models[9, 10] and the effective loop quantum cosmology (LQC)[11, 12] models. It is interesting to note that although the premises of the background QG theories are completely different from each other, there are some similarities and identical features that may be obtained from a class of the effective braneworld and LQC models, that may hint at some hidden correspondance between the two contrasting approaches. In this letter, we shall only talk about models that introduce corrections to standard GR at the ultraviolet (UV) scale as we are concerned with resolution of the initial singularity. Braneworld models have the feature that our universe is represented by a (3 + 1)-dimensional hypersurface known as the ’brane’ (which are objects appearing in M-theory) embedded in a higher dimensional bulk spacetime. The Randall Sundrum single brane model (RS-II) is one such model with a spacelike extra dimension, indicating that the signature of the bulk space is Lorentzian. If the signature of the bulk deviates from the former, then we can have a bulk signature (−, −, +, +, +) such that the braneworld has a timelike extra dimension. The standard model particles and fields are confined to the brane, while gravity is free to propagate in the bulk. This paper is available on arxiv under CC 4.0 license. Authors: (1) Rikpratik Sengupta, Department of Physics, Aliah University, Kolkata 700 160, West Bengal, India (E-mail addresses: rikpratik.sengupta@gmail.com(RS)) This paper is available on arxiv under CC 4.0 license. Authors: Authors: (1) Rikpratik Sengupta, Department of Physics, Aliah University, Kolkata 700 160, West Bengal, India (E-mail addresses: rikpratik.sengupta@gmail.com(RS)) Table of Links Abstract and Intro The cosmological model Discussion Acknowledgments References Abstract and Intro Abstract and Intro The cosmological model The cosmological model Discussion Discussion Acknowledgments Acknowledgments References References Abstract Keywords : oscillating universe, braneworld, bounce, turnaround, phantom. Keywords 1. Introduction The standard big bang model of cosmology is plagued by an initial singularity (at time t = 0), where the Friedmann equations describing the time evolution of the universe fails to render a plausible physical description of the space-time dynamics due to the diverging Hubble parameter H, which is a consequence of the infinitely large energy density prevailing in the very early universe. The scalar curvature R also diverges, implying that the initial singularity is a curvature singularity of the Ricci type, which are characterized by diverging energy densities. As shown in their famous singularity theorems by Hawking and Penrose, the initial big bang singularity cannot be avoided in a general relativistic (GR) setup provided the energy conditions are obeyed by matter filling up the universe[4, 5]. One of the key problems of the standard inflationary cosmology, besidies the ambiguity regarding the nature of the inflaton field is that, within the GR framework, inflation can not be past eternal[6]. So, if the inflation is preceeded by a radiation dominated phase, then the origin of the universe is singular. However, today many cosmologists are unhappy about the initial singularity and consider it to be a limitation of GR to describe space-times involving very large energy densities. If there is no big bang, then the possibilities are that the universe either experiences a quantum creation where there is a quantum mechanical tunelling into an inflationary phase, or it may be that the universe existed for an eternally long time in a quasi static state followed by an emergent inflationary phase, or there is a non-singular bounce replacing the singular big bang prior to which the universe contracts and following which the universe expands. In the context of GR, the emergent and bouncing scenarios can be realised effectively only for a spatially closed universe (k = 1). A fully consistent treatment of the first possibility considering quantum creation will most probably require a quantum gravity (QG) treatment. However, there is no fully understood and developed QG theory at the moment and the two most accepted theories being worked on in this context are M-theory[7] involving extra dimensions and Loop Quantum Gravity (LQG)[8]. M- theory requires eleven space-time dimension for its quantum consistency while LQG quantizes space-time itself in the usual four dimensions. Effective theories from both the scenarios have become popular in recent times in the form of the extra dimensional braneworld models[9, 10] and the effective loop quantum cosmology (LQC)[11, 12] models. It is interesting to note that although the premises of the background QG theories are completely different from each other, there are some similarities and identical features that may be obtained from a class of the effective braneworld and LQC models, that may hint at some hidden correspondance between the two contrasting approaches. In this letter, we shall only talk about models that introduce corrections to standard GR at the ultraviolet (UV) scale as we are concerned with resolution of the initial singularity. Braneworld models have the feature that our universe is represented by a (3 + 1)-dimensional hypersurface known as the ’brane’ (which are objects appearing in M-theory) embedded in a higher dimensional bulk spacetime. The Randall Sundrum single brane model (RS-II) is one such model with a spacelike extra dimension, indicating that the signature of the bulk space is Lorentzian. If the signature of the bulk deviates from the former, then we can have a bulk signature (−, −, +, +, +) such that the braneworld has a timelike extra dimension. The standard model particles and fields are confined to the brane, while gravity is free to propagate in the bulk.

Non-singular Oscillating Cosmology on Randall-Sundrum II: Abstract and Intro

র‌্যান্ডাল-সান্ড্রাম II-এ নন-সিঙ্গুলার অসিলেটিং কসমোলজি: অ্যাবস্ট্রাক্ট এবং ইন্ট্রো

Nicht-singuläre oszillierende Kosmologie auf Randall-Sundrum II: Zusammenfassung und Einführung

Cosmología oscilante no singular en Randall-Sundrum II: resumen e introducción

Cosmologie oscillante non singulière sur Randall-Sundrum II : résumé et introduction

रैंडल-सुंड्रम II पर गैर-विलक्षण दोलन ब्रह्मांड विज्ञान: सार और परिचय

ランドール・サンドラム II における非特異振動宇宙論: 概要と序論

Randall-Sundrum II의 비특이 진동 우주론: 요약 및 소개

Cosmologia Oscilante Não Singular em Randall-Sundrum II: Resumo e Introdução

Несингулярная осциллирующая космология по Рэндаллу-Сундраму II: Аннотация и введение

Randall-Sundrum II'de Tekil Olmayan Salınımlı Kozmoloji: Özet ve Giriş

Vũ trụ dao động không đơn lẻ trên Randall-Sundrum II: Tóm tắt và giới thiệu

Randall-Sundrum II 上的非奇异振荡宇宙学：摘要和简介

This paper is available on arxiv under CC 4.0 license.
Authors:
(1) Rikpratik Sengupta, Department of Physics, Aliah University, Kolkata 700 160, West Bengal, India (E-mail addresses: rikpratik.sengupta@gmail.com(RS)) Table of Links Abstract and Intro
The cosmological model
Discussion
Acknowledgments
References 3. Discussion When the universe is contracting, the energy density grows and ultimately diverges making the scalar curvature and the Hubble parameter to diverge as well. This can be understood by the fact that the scale factor vanishes in the Friedmann equation. Bounce is the mechanism that simply prevents the initial singularity from forming by making the scale factor begin to increase before it can reach zero or making the energy density drop off before it can diverge. The condition for bounce is achieved through ¨a > 0, such that the contracting universe starts expanding. Alternatively, in turnaround, the expanding universe must begin to start contracting so that both the scale factor and energy density do not diverge in the finite future and this can be achieved through the condition ¨a < 0. Both at the bounce and turnaround, the Hubble parameter vanishes rather than diverging. The the scale factor neither reaches zero or infinite value as the effective energy density on the brane remains finite. Thus, the universe transits smoothly through both the bounce and turnaround. For cosmology on the brane, both the mechanisms can be achieved by a minimum of requisite components- a scalar field with an inflationary potential and a DE component that violates the NEC. The problem with the phantom is that such an exotic fluid has a number of theoretical inconsitencies and pathologies at the quantum level that makes their existence questionable. The problem with the future singularities can be cured from the correction term on the brane as we have found, but such a fluid may also lead to the vacuum being unstable. Attempts to construct dynamical scalar field models of the phantom have led to a negative kinetic term[25] that in turn results in quantum instabilities[30]. However, there exists a cosmological model of DE with vanishing Λ where the vacuum energy obtained from the quantization of a free scalar field having low mass is described by a supernegative EoS and the model is free of pathologies at the quantum level[31]. Two problems in general feature in most oscillating cosmology models. We shall discuss them very briefly without going into much details before concluding the letter. The first problem is posed by the continued existence of singular objects like black holes from the area theorems of Hawking. However, before the turnaround leading up to the next bounce (via a contraction phase) in a phantom dominated universe, such structures may well be dissolved due to the extremely large gravitationally repulsive effects[32], thus being prevented from disrupting the evolution of the universe during the contracting phase following the turnaround. Infact, it has been shown that[33] the Hawking area theorems may not hold true if the NEC (ρ + p ≥ 0) is violated, as is the case for a phantom dominated universe. Any surviving remnant microscopic black holes may act as possible dark matter candidates. Moreover, the black hole singularity may also be resolved in the UV corrected picture just like the initial big bang and the big rip singularities and also, there may exist non-singular black hole mimickers like gravastar on the brane[34], leading to a complete resolution of the problem at once. It is worth mentioning in this context that the RSII braneworld has also been used in explaining a recent GW event GW170817[35] and the recent observation of the dark shadow of M87∗ [36]. The second problem is associated with the entropy of the universe, which we think remains the same in a periodic manner after the bounce over each cycle, such that the possible increase in entropy during the expanding phase being compensated by a possible decreasing during the radiation/matter dominated expanding phase. This prevents the enrtopy to increase to infinitely large values limiting the number of cycles. We are however concerned mainly with the bounce and turnaround in a single cycle in this letter. This is the first model that can avert the initial singularity using a single brane approach with a positive brane tension. Braneworlds that have a space-like extra dimension like the one we have considered here are characterized by a positive brane tension (as the effective gravitational constant on the brane needs to be positive to explain the attractive nature of gravity) but such a setup could not resolve the big bang singularity. The non-singular models of brane cosmology till date have either resorted to a single brane with time-like extra dimension where no scalar field has to be invoked to generate the bounce which happens naturally from the cosmological dynamics[10], but the brane tension must be negative for the same reason of obtaining a positive effective gravitational constant, or alternatively, introduce a second braneworld with a negative tension parallel to the positive tension brane with finite separation between the branes. The advantage of introducing the parallel negative tension braneworld is two-fold: firstly, negative tension branes have the unique feature of reduced inertia on matter with positive energy density being dumped onto it helping the dynamical realization, and secondly the two brane setup comes with the benefit of a scalar field known as the radion which modulates the inter-brane separation and can both source the bounce at early times as well as behave like phantom dark energy at late times dure to the non-canonical kinetic term evolving to have a negative value[37]. However, there are some tachyonic instabilities associated with negative tension braneworlds which can be possibly resolved in M-theory but has not been explored well enough and requires further formal developments in M-theory (although the properties are really appealing). On the contrary, the ingredients of our model are well explored and the physics is more well understood in terms of a single positive tension brane. The phantom dark energy also does not lead up to the big rip as the quadratic correction to stress energy becomes significant before the singularity can is reached. Also, the scalar field we have used is a physically well motivated one, since it can accommodate the inflationary scenario naturally and its potential need not be reconstructed to explain the generation of seed cosmological perturbations. Most models of cosmology with a nonsingular bounce have either to resort to alternative mechanisms to generate seed perturbations that are not very well understood physically, or have to reconstruct the potential on an ad hoc basis to generate the perturbations, but in our model an inflationary epoch following the bounce driven by the scalar field with an inflationary emergent potential already has all the ingredients responsible for generating these perturbations, and is well understood. We may think of it as a toy model, not because the scenario is physically ill-motivated, but since we have not tested the model against observations. We plan to analyze the primordial observables like the amplitude of scalar perturbations, tensor to scalar ratio and the spectral index and test them against latest observations in a follow up work in the recent future. This paper is available on arxiv under CC 4.0 license. Authors: (1) Rikpratik Sengupta, Department of Physics, Aliah University, Kolkata 700 160, West Bengal, India (E-mail addresses: rikpratik.sengupta@gmail.com(RS)) This paper is available on arxiv under CC 4.0 license. Authors: Authors: (1) Rikpratik Sengupta, Department of Physics, Aliah University, Kolkata 700 160, West Bengal, India (E-mail addresses: rikpratik.sengupta@gmail.com(RS)) Table of Links Abstract and Intro The cosmological model Discussion Acknowledgments References Abstract and Intro Abstract and Intro The cosmological model The cosmological model Discussion Discussion Acknowledgments Acknowledgments References References 3. Discussion When the universe is contracting, the energy density grows and ultimately diverges making the scalar curvature and the Hubble parameter to diverge as well. This can be understood by the fact that the scale factor vanishes in the Friedmann equation. Bounce is the mechanism that simply prevents the initial singularity from forming by making the scale factor begin to increase before it can reach zero or making the energy density drop off before it can diverge. The condition for bounce is achieved through ¨a > 0, such that the contracting universe starts expanding. Alternatively, in turnaround, the expanding universe must begin to start contracting so that both the scale factor and energy density do not diverge in the finite future and this can be achieved through the condition ¨a < 0. Both at the bounce and turnaround, the Hubble parameter vanishes rather than diverging. The the scale factor neither reaches zero or infinite value as the effective energy density on the brane remains finite. Thus, the universe transits smoothly through both the bounce and turnaround. For cosmology on the brane, both the mechanisms can be achieved by a minimum of requisite components- a scalar field with an inflationary potential and a DE component that violates the NEC. The problem with the phantom is that such an exotic fluid has a number of theoretical inconsitencies and pathologies at the quantum level that makes their existence questionable. The problem with the future singularities can be cured from the correction term on the brane as we have found, but such a fluid may also lead to the vacuum being unstable. Attempts to construct dynamical scalar field models of the phantom have led to a negative kinetic term[25] that in turn results in quantum instabilities[30]. However, there exists a cosmological model of DE with vanishing Λ where the vacuum energy obtained from the quantization of a free scalar field having low mass is described by a supernegative EoS and the model is free of pathologies at the quantum level[31]. Two problems in general feature in most oscillating cosmology models. We shall discuss them very briefly without going into much details before concluding the letter. The first problem is posed by the continued existence of singular objects like black holes from the area theorems of Hawking. However, before the turnaround leading up to the next bounce (via a contraction phase) in a phantom dominated universe, such structures may well be dissolved due to the extremely large gravitationally repulsive effects[32], thus being prevented from disrupting the evolution of the universe during the contracting phase following the turnaround. Infact, it has been shown that[33] the Hawking area theorems may not hold true if the NEC (ρ + p ≥ 0) is violated, as is the case for a phantom dominated universe. Any surviving remnant microscopic black holes may act as possible dark matter candidates. Moreover, the black hole singularity may also be resolved in the UV corrected picture just like the initial big bang and the big rip singularities and also, there may exist non-singular black hole mimickers like gravastar on the brane[34], leading to a complete resolution of the problem at once. It is worth mentioning in this context that the RSII braneworld has also been used in explaining a recent GW event GW170817[35] and the recent observation of the dark shadow of M87∗ [36]. The second problem is associated with the entropy of the universe, which we think remains the same in a periodic manner after the bounce over each cycle, such that the possible increase in entropy during the expanding phase being compensated by a possible decreasing during the radiation/matter dominated expanding phase. This prevents the enrtopy to increase to infinitely large values limiting the number of cycles. We are however concerned mainly with the bounce and turnaround in a single cycle in this letter. This is the first model that can avert the initial singularity using a single brane approach with a positive brane tension. Braneworlds that have a space-like extra dimension like the one we have considered here are characterized by a positive brane tension (as the effective gravitational constant on the brane needs to be positive to explain the attractive nature of gravity) but such a setup could not resolve the big bang singularity. The non-singular models of brane cosmology till date have either resorted to a single brane with time-like extra dimension where no scalar field has to be invoked to generate the bounce which happens naturally from the cosmological dynamics[10], but the brane tension must be negative for the same reason of obtaining a positive effective gravitational constant, or alternatively, introduce a second braneworld with a negative tension parallel to the positive tension brane with finite separation between the branes. The advantage of introducing the parallel negative tension braneworld is two-fold: firstly, negative tension branes have the unique feature of reduced inertia on matter with positive energy density being dumped onto it helping the dynamical realization, and secondly the two brane setup comes with the benefit of a scalar field known as the radion which modulates the inter-brane separation and can both source the bounce at early times as well as behave like phantom dark energy at late times dure to the non-canonical kinetic term evolving to have a negative value[37]. However, there are some tachyonic instabilities associated with negative tension braneworlds which can be possibly resolved in M-theory but has not been explored well enough and requires further formal developments in M-theory (although the properties are really appealing). On the contrary, the ingredients of our model are well explored and the physics is more well understood in terms of a single positive tension brane. The phantom dark energy also does not lead up to the big rip as the quadratic correction to stress energy becomes significant before the singularity can is reached. Also, the scalar field we have used is a physically well motivated one, since it can accommodate the inflationary scenario naturally and its potential need not be reconstructed to explain the generation of seed cosmological perturbations. Most models of cosmology with a nonsingular bounce have either to resort to alternative mechanisms to generate seed perturbations that are not very well understood physically, or have to reconstruct the potential on an ad hoc basis to generate the perturbations, but in our model an inflationary epoch following the bounce driven by the scalar field with an inflationary emergent potential already has all the ingredients responsible for generating these perturbations, and is well understood. We may think of it as a toy model, not because the scenario is physically ill-motivated, but since we have not tested the model against observations. We plan to analyze the primordial observables like the amplitude of scalar perturbations, tensor to scalar ratio and the spectral index and test them against latest observations in a follow up work in the recent future.

Non-singular Oscillating Cosmology on Randall-Sundrum II: Discussion

নন-সিঙ্গুলার অসিলেটিং কসমোলজি অন র‍্যান্ডাল-সান্ড্রাম II: আলোচনা

Nicht-singuläre oszillierende Kosmologie auf Randall-Sundrum II: Diskussion

Cosmología oscilante no singular en Randall-Sundrum II: discusión

Cosmologie oscillante non singulière sur Randall-Sundrum II : discussion

रैंडल-सुंड्रम II पर गैर-विलक्षण दोलन ब्रह्मांड विज्ञान: चर्चा

ランドール・サンドラム II における非特異振動宇宙論: 議論

Randall-Sundrum II에 관한 비특이 진동 우주론: 토론

Cosmologia Oscilante Não Singular em Randall-Sundrum II: Discussão

Несингулярная осциллирующая космология на Рэндалле-Сундраме II: обсуждение

Randall-Sundrum II'de Tekil Olmayan Salınımlı Kozmoloji: Tartışma

Vũ trụ dao động không đơn lẻ trên Randall-Sundrum II: Thảo luận

兰德尔-桑德拉姆 II 的非奇异振荡宇宙学：讨论

This paper is available on arxiv under CC 4.0 license.
Authors:
(1) Rikpratik Sengupta, Department of Physics, Aliah University, Kolkata 700 160, West Bengal, India (E-mail addresses: rikpratik.sengupta@gmail.com(RS)) Table of Links Abstract and Intro
The cosmological model
Discussion
Acknowledgments
References 2. The cosmological model The Einstein Field Equations (EFE) on the brane have the general form For the FRW line element describing an isotropic, homogenous universe, the modified EFE on the brane has the form However, in this letter we shall try to construct a novel non-singular cosmological model of oscillating nature on the spatially flat RS II brane with a spacelike extra dimension (ǫ = 1). For a spacelike extra dimension ǫ being positive, the Hubble parameter does not vanish naturally if the energy density ρ rises upto 2σ. So, RS II cosmology does not contain any inherent feature through which a non-singular bounce can be naturally realized. A Weyl curvature singularity due to infinitely large tidal forces at the wormhole throat can be resolved on the RS II brane with ordinary matter[17]. We shall try to induce the bounce using an ingredient that is quite familiar in early universe cosmology and finds application in achieving the inflationary mechanism- a scalar field. The scalar field is minimally coupled meaning that there is no coupling between the scalar field and gravity. In such a model there may exist an infinite number of cycles containing expansion and contraction phases. However, another additional mechanism is required besides a non-singular bounce to generate such an oscillating universe. The universe must begin to contract at late times following an expanding phase before the next cycle begins. This mechanism is known as the turnaround. We shall use two different mechanisms to generate the bounce and turnaround on the flat RS II brane. The time evolution of the scalar field has also been plotted in Figure 1. As evident from the figure (estimating the time of the bounce from Figure 2), negative values of the field play an important role in the bounce. So, from the evolution of the potential, it may be said that the bounce happens for the flatter branch of the potential that leads to an emergent cosmology in a closed relativistic Friedmann universe. We now move on to the late time where the universe is in an accelerating phase. Such a phase has been inferred from astronomical observations[19, 20]. With the discovery of the accelerating universe, there was a resurrection of the Λ-term in cosmology. However, there are certain inconsistencies with the Λ dark energy (DE) that has lead to a wide range of models including quintessence involving scalar fields[21, 22], Chaplygin gas involving fluids with nonlinear equation of states[23, 24] (EoS), the phantom with an exotic EoS[25, 26] and geometrical models which effectively modify the matter sector through geometrical contributions at the infrared (IR) scale[27, 28, 29] but not the real source matter. Here, we have already used a framework in which the geometrical contributions modify the matter sector effectively at the UV scale through the ρ 2 term. If such a term has to be significant in the universe at late times to source a turnaround through its possible non-conventional behaviour (H ∝ ρ), then there has to be a mechanism to make the energy density of the universe grow sufficiently large enough. There is a possibility to achieve this using one of the possible DE candidates that is observationally well favoured-the phantom. The phantom is an exotic fluid with a supernegative EoS (ω < −1) violating the Null Energy condition (NEC), proposed by Caldwell[25] to fit the observational data. The fact tha the phantom fits quite well with the observational data (−1.61 < ω < −0.78) has latter been verified by a number of groups[1, 2, 3]. Again making use of the UV corrected Friedmann equation on the brane, we obtain where α is a constant. We obtain analytical solutions for three different values of the EoS parameter, considering a phantom dominated universe. As we find from Figure 3 on plotiing the scale factor with time, the accelerating phantom dominated universe enters into a contracting phase before the scale factor diverges. Once the universe begins to contract, it is dominated by radiation or matter until the scalar field begins to dominate the universe that causes it to bounce before the scale factor reaches a zero value. So, the scale factor maintains a non zero finite value all along the evolution of the universe, never reaching a singular state. The energy density of the universe has also been plotted in Figure 3 as it evolves with time close to the turnaround. It is found to reach a peak just before the turnaround as it keeps on increasing in the phantom dominated eoch, before falling off again. The energy density is large enough at both early and late times to make the quadratic correction term in the modified EFE significant, but never diverges. It starts dropping following both the bounce and turnaround. This paper is available on arxiv under CC 4.0 license. Authors: (1) Rikpratik Sengupta, Department of Physics, Aliah University, Kolkata 700 160, West Bengal, India (E-mail addresses: rikpratik.sengupta@gmail.com(RS)) This paper is available on arxiv under CC 4.0 license. Authors: Authors: (1) Rikpratik Sengupta, Department of Physics, Aliah University, Kolkata 700 160, West Bengal, India (E-mail addresses: rikpratik.sengupta@gmail.com(RS)) Table of Links Abstract and Intro The cosmological model Discussion Acknowledgments References Abstract and Intro Abstract and Intro The cosmological model The cosmological model Discussion Discussion Acknowledgments Acknowledgments References References 2. The cosmological model The Einstein Field Equations (EFE) on the brane have the general form For the FRW line element describing an isotropic, homogenous universe, the modified EFE on the brane has the form However, in this letter we shall try to construct a novel non-singular cosmological model of oscillating nature on the spatially flat RS II brane with a spacelike extra dimension (ǫ = 1). For a spacelike extra dimension ǫ being positive, the Hubble parameter does not vanish naturally if the energy density ρ rises upto 2σ. So, RS II cosmology does not contain any inherent feature through which a non-singular bounce can be naturally realized. A Weyl curvature singularity due to infinitely large tidal forces at the wormhole throat can be resolved on the RS II brane with ordinary matter[17]. We shall try to induce the bounce using an ingredient that is quite familiar in early universe cosmology and finds application in achieving the inflationary mechanism- a scalar field. The scalar field is minimally coupled meaning that there is no coupling between the scalar field and gravity. In such a model there may exist an infinite number of cycles containing expansion and contraction phases. However, another additional mechanism is required besides a non-singular bounce to generate such an oscillating universe. The universe must begin to contract at late times following an expanding phase before the next cycle begins. This mechanism is known as the turnaround. We shall use two different mechanisms to generate the bounce and turnaround on the flat RS II brane. The time evolution of the scalar field has also been plotted in Figure 1. As evident from the figure (estimating the time of the bounce from Figure 2), negative values of the field play an important role in the bounce. So, from the evolution of the potential, it may be said that the bounce happens for the flatter branch of the potential that leads to an emergent cosmology in a closed relativistic Friedmann universe. We now move on to the late time where the universe is in an accelerating phase. Such a phase has been inferred from astronomical observations[19, 20]. With the discovery of the accelerating universe, there was a resurrection of the Λ-term in cosmology. However, there are certain inconsistencies with the Λ dark energy (DE) that has lead to a wide range of models including quintessence involving scalar fields[21, 22], Chaplygin gas involving fluids with nonlinear equation of states[23, 24] (EoS), the phantom with an exotic EoS[25, 26] and geometrical models which effectively modify the matter sector through geometrical contributions at the infrared (IR) scale[27, 28, 29] but not the real source matter. Here, we have already used a framework in which the geometrical contributions modify the matter sector effectively at the UV scale through the ρ 2 term. If such a term has to be significant in the universe at late times to source a turnaround through its possible non-conventional behaviour (H ∝ ρ), then there has to be a mechanism to make the energy density of the universe grow sufficiently large enough. There is a possibility to achieve this using one of the possible DE candidates that is observationally well favoured-the phantom. The phantom is an exotic fluid with a supernegative EoS (ω < −1) violating the Null Energy condition (NEC), proposed by Caldwell[25] to fit the observational data. The fact tha the phantom fits quite well with the observational data (−1.61 < ω < −0.78) has latter been verified by a number of groups[1, 2, 3]. Again making use of the UV corrected Friedmann equation on the brane, we obtain where α is a constant. We obtain analytical solutions for three different values of the EoS parameter, considering a phantom dominated universe. As we find from Figure 3 on plotiing the scale factor with time, the accelerating phantom dominated universe enters into a contracting phase before the scale factor diverges. Once the universe begins to contract, it is dominated by radiation or matter until the scalar field begins to dominate the universe that causes it to bounce before the scale factor reaches a zero value. So, the scale factor maintains a non zero finite value all along the evolution of the universe, never reaching a singular state. The energy density of the universe has also been plotted in Figure 3 as it evolves with time close to the turnaround. It is found to reach a peak just before the turnaround as it keeps on increasing in the phantom dominated eoch, before falling off again. The energy density is large enough at both early and late times to make the quadratic correction term in the modified EFE significant, but never diverges. It starts dropping following both the bounce and turnaround.

Non-singular Oscillating Cosmology on Randall-Sundrum II: The cosmological model

র‍্যান্ডাল-সান্ড্রাম II-তে অ-একবচন অসিলেটিং কসমোলজি: মহাজাগতিক মডেল

Nicht-singuläre oszillierende Kosmologie nach Randall-Sundrum II: Das kosmologische Modell

Cosmología oscilante no singular en Randall-Sundrum II: el modelo cosmológico

Cosmologie oscillante non singulière sur Randall-Sundrum II : le modèle cosmologique

रैंडल-सुंड्रम II पर गैर-विलक्षण दोलन ब्रह्मांड विज्ञान: ब्रह्मांड संबंधी मॉडल

ランドール・サンドラムの非特異振動宇宙論 II: 宇宙論モデル

Randall-Sundrum II의 비특이 진동 우주론: 우주론 모델

Cosmologia Oscilante Não Singular em Randall-Sundrum II: O modelo cosmológico

Несингулярная осциллирующая космология по Рэндаллу-Сундраму II: космологическая модель

Randall-Sundrum II'de Tekil Olmayan Salınımlı Kozmoloji: Kozmolojik model

Vũ trụ dao động không đơn lẻ trên Randall-Sundrum II: Mô hình vũ trụ

基于兰德尔-桑德拉姆的非奇异振荡宇宙学 II：宇宙学模型

This paper is available on arxiv under CC 4.0 license.
Authors:
(1) Nicolas Bernal, New York University Abu Dhabi;
(2) Partha Konar, Physical Research Laboratory;
(3) Sudipta Show, Physical Research Laboratory. Table of Links Abstract and Intro
S-matrix: Unitarity and its Consequences
Dark Matter Annihilation and Unitarity Bound
Low-temperature Reheating
Freeze-out with a Low-temperature Reheating
Summary and Conclusion
Acknowledgments and References 4. Low-temperature Reheating where T corresponds to the temperature of the SM bath. It follows that the Hubble expansion rate H is therefore the SM entropy density implies that the temperature of the SM bath scales as However, it is interesting to emphasize that the standard cosmological scenario is not granted and that alternative cosmologies could also have occurred [121]. In the following, we focus on cases characterized by low-temperature reheating. This reheating could correspond to the period just after the end of inflation, or to a secondary period in which an extra component beyond SM radiation dominated the energy density of the universe. In particular, two scenarios will be reviewed: one where the extra component ϕ that dominated the expansion of the universe has an energy density that gets diluted faster than radiation and does not decay (that is, a kination-like scenario), and the other where ϕ scales as nonrelativistic matter and decays into SM particles (that is, an early matter-dominated scenario). These two scenarios will be described below. 4.1. Kination-like In this scenario, the universe was dominated by a component ϕ whose energy density redshifts faster than free radiation [113], as with n > 0. A typical example of this scenario corresponds to kination [122, 123], where n = 2. However, larger values for n are also possible, appearing, for example, in the context of ekpyrotic [124, 125] or cyclic scenarios [126–129]. where we have taken into account that, as ϕ is not decaying, the SM entropy is conserved, and therefore the SM temperature follows the standard scaling shown in Eq. (4.4). 4.2. Early matter domination It follows that the Hubble expansion rate is Having settled the evolution of the background, in the next section the dynamics of the thermal DM in such alternative cosmological scenarios, and in particular the impact on the unitarity limit, will be carefully studied. [4] It is worth mentioning that, in general, the non-adiabatic period could have been preceded by an adiabatic period with ϕ-domination, and by another era dominated by SM radiation. Here, however, we assume that the DM freeze-out happens in the non-adiabatic period so that previous stages of the universe play no role. This is true if ϕ is identified with the inflaton or simply if the nonadiabatic era is long enough. This paper is available on arxiv under CC 4.0 license. Authors: (1) Nicolas Bernal, New York University Abu Dhabi; (2) Partha Konar, Physical Research Laboratory; (3) Sudipta Show, Physical Research Laboratory. This paper is available on arxiv under CC 4.0 license. Authors: Authors: (1) Nicolas Bernal, New York University Abu Dhabi; (2) Partha Konar, Physical Research Laboratory; (3) Sudipta Show, Physical Research Laboratory. Table of Links Abstract and Intro S-matrix: Unitarity and its Consequences Dark Matter Annihilation and Unitarity Bound Low-temperature Reheating Freeze-out with a Low-temperature Reheating Summary and Conclusion Acknowledgments and References Abstract and Intro Abstract and Intro S-matrix: Unitarity and its Consequences S-matrix: Unitarity and its Consequences Dark Matter Annihilation and Unitarity Bound Dark Matter Annihilation and Unitarity Bound Low-temperature Reheating Low-temperature Reheating Freeze-out with a Low-temperature Reheating Freeze-out with a Low-temperature Reheating Summary and Conclusion Summary and Conclusion Acknowledgments and References Acknowledgments and References 4. Low-temperature Reheating where T corresponds to the temperature of the SM bath. It follows that the Hubble expansion rate H is therefore T H the SM entropy density implies that the temperature of the SM bath scales as However, it is interesting to emphasize that the standard cosmological scenario is not granted and that alternative cosmologies could also have occurred [121]. In the following, we focus on cases characterized by low-temperature reheating. This reheating could correspond to the period just after the end of inflation, or to a secondary period in which an extra component beyond SM radiation dominated the energy density of the universe. In particular, two scenarios will be reviewed: one where the extra component ϕ that dominated the expansion of the universe has an energy density that gets diluted faster than radiation and does not decay (that is, a kination-like scenario), and the other where ϕ scales as nonrelativistic matter and decays into SM particles (that is, an early matter-dominated scenario). These two scenarios will be described below. 4.1. Kination-like In this scenario, the universe was dominated by a component ϕ whose energy density redshifts faster than free radiation [113], as with n > 0. A typical example of this scenario corresponds to kination [122, 123], where n = 2. However, larger values for n are also possible, appearing, for example, in the context of ekpyrotic [124, 125] or cyclic scenarios [126–129]. where we have taken into account that, as ϕ is not decaying, the SM entropy is conserved, and therefore the SM temperature follows the standard scaling shown in Eq. (4.4). 4.2. Early matter domination It follows that the Hubble expansion rate is Having settled the evolution of the background, in the next section the dynamics of the thermal DM in such alternative cosmological scenarios, and in particular the impact on the unitarity limit, will be carefully studied. [4] It is worth mentioning that, in general, the non-adiabatic period could have been preceded by an adiabatic period with ϕ-domination, and by another era dominated by SM radiation. Here, however, we assume that the DM freeze-out happens in the non-adiabatic period so that previous stages of the universe play no role. This is true if ϕ is identified with the inflaton or simply if the nonadiabatic era is long enough.

Unitarity Bound on Dark Matter: Low-temperature Reheating

ডার্ক ম্যাটারে ঐক্যবদ্ধতা: নিম্ন-তাপমাত্রা পুনরায় গরম করা

Unitaritätsgrenze für Dunkle Materie: Wiedererwärmung bei niedrigen Temperaturen

Unitaridad unida a la materia oscura: recalentamiento a baja temperatura

Unitarité liée à la matière noire : réchauffage à basse température

डार्क मैटर पर यूनिटैरिटी बाउंड: कम तापमान पर पुनः गर्म करना

暗黒物質のユニタリー性限界：低温再加熱

암흑물질의 단일성: 저온 재가열

Unitariedade vinculada à matéria escura: reaquecimento em baixa temperatura

Унитарность, связанная с темной материей: низкотемпературный разогрев

Karanlık Maddeye Bağlı Birlik: Düşük Sıcaklıkta Yeniden Isıtma

Sự thống nhất bị ràng buộc trên vật chất tối: Làm nóng lại ở nhiệt độ thấp

暗物质的幺正性界限：低温再加热

This paper is available on arxiv under CC 4.0 license.
Authors:
(1) Vitor da Fonseca, Instituto de Astrof´ısica e Ciˆencias do Espa¸co, Faculdade de Ciˆencias da Universidade de Lisboa;
(2) Tiago Barreiro, Instituto de Astrof´ısica e Ciˆencias do Espa¸co, Faculdade de Ciˆencias da Universidade de Lisboa and 2ECEO, Universidade Lus´ofona;
(3) Nelson J. Nunes, Instituto de Astrof´ısica e Ciˆencias do Espa¸co, Faculdade de Ciˆencias da Universidade de Lisboa. Table of Links Abstract and Intro
Coupling Dark Energy to Neutrinos
Impact of the Coupling on Perturbations and Observables
Parameter Estimation
Discussion
Acknowledgment, Appendix, and References Abstract I. INTRODUCTION The standard hot Big Bang model predicts that the Universe is filled with a background of thermal relic neutrinos, called the cosmic neutrino background (CνB), with a temperature and density of the order of the cosmic microwave background (CMB) photons [1, 2]. Neutrinos are held in thermal equilibrium with the primordial plasma by electroweak interactions until the temperature of the Universe drops to T ≃ 1 MeV. Below this temperature, they decouple from the thermal bath and flow freely along geodesics of spacetime. Since the neutrinos are still ultrarelativistic when they decouple, they retain a relativistic Fermi-Dirac distribution even though they are no longer in thermal equilibrium. Not being subjected to the Boltzmann exponential suppression, we have far more neutrinos than would otherwise be expected. Although relic neutrinos are very abundant, there is still no direct evidence for their background because it is hard to detect at low energy level, given that they have a very small cross section with matter. There is only indirect evidence for the CνB, mainly through gravitational interactions, for which theoretical predictions are in excellent agreement with observations of the CMB and large-scale structure. In this work, we investigate whether it is possible to relax the existing cosmological upper limit on the neutrino mass through a possible interaction between the neutrino fluid and the dark energy component [11, 12] given by a scalar field. We consider a mass-varying neutrino (MaVaN) scenario, where the coupling leads to an effective neutrino mass that depends on the value of the field [13–21]. We employ a minimal parametrization where the scalar field depends linearly on the number of e-folds [22]. It limits the number of additional parameters with respect to the concordance model and alleviates the initial conditions problem [23] thanks to the scaling behavior of the field at early times. Such parametrization has been used in the context of testing a coupling between quintessence and the electromagnetic sector, and scalar field – dark matter interactions [24–26], but never utilized in the context of neutrino interactions. By testing the model with a particular data set that combines observations of the CMB, structure growth, and background expansion, we show that the constraint on today’s mass is weakened by neutrinos of growing mass [27, 28] that receive energy from the quintessence component over cosmic time. A mechanism that couples the scalar field, as early dark energy, to the neutrinos has been proposed [29, 30] to alleviate the Hubble tension, i.e. the discrepancy between the H0 determinations of high and low redshift probes [9, 31–33], but it remains to be tested with cosmological observations. Nevertheless, the Hubble tension is not the subject of this paper, since the early dark energy component in our model is insufficient to affect it. This paper is available on arxiv under CC 4.0 license. Authors: (1) Vitor da Fonseca, Instituto de Astrof´ısica e Ciˆencias do Espa¸co, Faculdade de Ciˆencias da Universidade de Lisboa; (2) Tiago Barreiro, Instituto de Astrof´ısica e Ciˆencias do Espa¸co, Faculdade de Ciˆencias da Universidade de Lisboa and 2ECEO, Universidade Lus´ofona; (3) Nelson J. Nunes, Instituto de Astrof´ısica e Ciˆencias do Espa¸co, Faculdade de Ciˆencias da Universidade de Lisboa. This paper is available on arxiv under CC 4.0 license. Authors: Authors: (1) Vitor da Fonseca, Instituto de Astrof´ısica e Ciˆencias do Espa¸co, Faculdade de Ciˆencias da Universidade de Lisboa; (2) Tiago Barreiro, Instituto de Astrof´ısica e Ciˆencias do Espa¸co, Faculdade de Ciˆencias da Universidade de Lisboa and 2ECEO, Universidade Lus´ofona; (3) Nelson J. Nunes, Instituto de Astrof´ısica e Ciˆencias do Espa¸co, Faculdade de Ciˆencias da Universidade de Lisboa. Table of Links Abstract and Intro Coupling Dark Energy to Neutrinos Impact of the Coupling on Perturbations and Observables Parameter Estimation Discussion Acknowledgment, Appendix, and References Abstract and Intro Abstract and Intro Coupling Dark Energy to Neutrinos Coupling Dark Energy to Neutrinos Impact of the Coupling on Perturbations and Observables Impact of the Coupling on Perturbations and Observables Parameter Estimation Parameter Estimation Discussion Discussion Acknowledgment, Appendix, and References Acknowledgment, Appendix, and References Abstract I. INTRODUCTION The standard hot Big Bang model predicts that the Universe is filled with a background of thermal relic neutrinos, called the cosmic neutrino background (CνB), with a temperature and density of the order of the cosmic microwave background (CMB) photons [1, 2]. Neutrinos are held in thermal equilibrium with the primordial plasma by electroweak interactions until the temperature of the Universe drops to T ≃ 1 MeV. Below this temperature, they decouple from the thermal bath and flow freely along geodesics of spacetime. Since the neutrinos are still ultrarelativistic when they decouple, they retain a relativistic Fermi-Dirac distribution even though they are no longer in thermal equilibrium. Not being subjected to the Boltzmann exponential suppression, we have far more neutrinos than would otherwise be expected. Although relic neutrinos are very abundant, there is still no direct evidence for their background because it is hard to detect at low energy level, given that they have a very small cross section with matter. There is only indirect evidence for the CνB, mainly through gravitational interactions, for which theoretical predictions are in excellent agreement with observations of the CMB and large-scale structure. In this work, we investigate whether it is possible to relax the existing cosmological upper limit on the neutrino mass through a possible interaction between the neutrino fluid and the dark energy component [11, 12] given by a scalar field. We consider a mass-varying neutrino (MaVaN) scenario, where the coupling leads to an effective neutrino mass that depends on the value of the field [13–21]. We employ a minimal parametrization where the scalar field depends linearly on the number of e-folds [22]. It limits the number of additional parameters with respect to the concordance model and alleviates the initial conditions problem [23] thanks to the scaling behavior of the field at early times. Such parametrization has been used in the context of testing a coupling between quintessence and the electromagnetic sector, and scalar field – dark matter interactions [24–26], but never utilized in the context of neutrino interactions. By testing the model with a particular data set that combines observations of the CMB, structure growth, and background expansion, we show that the constraint on today’s mass is weakened by neutrinos of growing mass [27, 28] that receive energy from the quintessence component over cosmic time. A mechanism that couples the scalar field, as early dark energy, to the neutrinos has been proposed [29, 30] to alleviate the Hubble tension, i.e. the discrepancy between the H 0 determinations of high and low redshift probes [9, 31–33], but it remains to be tested with cosmological observations. Nevertheless, the Hubble tension is not the subject of this paper, since the early dark energy component in our model is insufficient to affect it. H

Relaxing cosmological constraints on current neutrino masses: Abstract and Intro

বর্তমান নিউট্রিনো ভরের উপর শিথিল করা মহাজাগতিক সীমাবদ্ধতা: বিমূর্ত এবং ভূমিকা

Lockerung der kosmologischen Beschränkungen für aktuelle Neutrinomassen: Zusammenfassung und Einführung

Relajación de las restricciones cosmológicas sobre las masas actuales de neutrinos: resumen e introducción

Assouplir les contraintes cosmologiques sur les masses actuelles des neutrinos : résumé et introduction

वर्तमान न्यूट्रिनो द्रव्यमान पर ब्रह्माण्ड संबंधी बाधाओं को शिथिल करना: सार और परिचय

現在のニュートリノ質量に対する宇宙論的制約の緩和: 概要と序論

현재 중성미자 질량에 대한 우주론적 제약 완화: 요약 및 소개

Relaxando as restrições cosmológicas nas massas atuais de neutrinos: Resumo e introdução

Ослабление космологических ограничений на текущие массы нейтрино: Аннотация и введение

Mevcut Nötrino Kütleleri Üzerindeki Kozmolojik Kısıtlamaların Gevşetilmesi: Özet ve Giriş

Nới lỏng các ràng buộc vũ trụ học đối với khối lượng neutrino hiện tại: Tóm tắt và Giới thiệu

放宽对当前中微子质量的宇宙学限制：摘要和简介

This paper is available on arxiv under CC 4.0 license.
Authors:
(1) A. Oliveros, Programa de F´ısica, Universidad del Atl´antico;
(2) Mario A. Acero, Programa de F´ısica, Universidad del Atl´antico. Table of Links Abstract and Intro
The f(Q) gravity: a brief review
Cosmological dynamics in late-time
Parameter constraints
Conclusions
Acknowledgments and References 3. Cosmological dynamics in late-time In this section, we implement the above results taking into account a particular choice for f(Q), and study the resulting late-time cosmological evolution at the background level. To begin with, we introduce the f(Q) gravity model, which plays a central role in this work: where Λ is the cosmological constant, and b and n are real dimensionless parameters. This model is inspired in that studied in Refs. [47, 48, 49], but in the context of f(R) gravity. It is evident that for b = 0 the model given by Eq. (23) is equivalent to GR plus the cosmological constant. In particular, from the structure of this model, it can be seen as a perturbative deviation from the ΛCDM Lagrangian. In this sense, this model can be arbitrarily close to ΛCDM, depending on the parameter b. It should be highlighted that in the literature also other exponential f(Q) gravity models have been intensively studied (see e.g., Refs. [18, 24, 25, 26, 31, 32, 33, 36]). Following the procedure carried out in Ref. [50], we rewrite Eq. (13) in terms of N = ln a Now, replacing Eqs. (29) and (30) in Eq. (28), and using Eq. (27), we obtain an approximate solution for the Hubble parameter H(z): similarly, the deceleration parameter q is given by where the prime denotes differentiation with respect to z. Using Eqs. (19) and (31) and considering up to second order expansion in b, we obtain approximated analytical expressions for the above parameters in terms of the redshift z, as follows: and Notice that, as it would have been expected, the terms independent of b in each one of the last expressions correspond to those associate to ΛCDM model. With Eqs. (36)-(39), we can plot the evolution of each parameter in terms of the redshift z. Additionally, in order to compare the results with the ΛCDM model, we have also incorporated in the corresponding plots the behavior associated with each quantity defined by Eqs. (32)-(35), but using Eq. (27) instead of (31). In general, from above we can deduce that as the magnitude of b increases, the present model deviates from ΛCDM model. This behavior is the expected, since by construction our approximated solution for H(z) is built as a perturbation of the ΛCDM model solution This paper is available on arxiv under CC 4.0 license. Authors: (1) A. Oliveros, Programa de F´ısica, Universidad del Atl´antico; (2) Mario A. Acero, Programa de F´ısica, Universidad del Atl´antico. This paper is available on arxiv under CC 4.0 license. Authors: Authors: (1) A. Oliveros, Programa de F´ısica, Universidad del Atl´antico; (2) Mario A. Acero, Programa de F´ısica, Universidad del Atl´antico. Table of Links Abstract and Intro The f(Q) gravity: a brief review Cosmological dynamics in late-time Parameter constraints Conclusions Acknowledgments and References Abstract and Intro Abstract and Intro The f(Q) gravity: a brief review The f(Q) gravity: a brief review Cosmological dynamics in late-time Cosmological dynamics in late-time Parameter constraints Parameter constraints Conclusions Conclusions Acknowledgments and References Acknowledgments and References 3. Cosmological dynamics in late-time In this section, we implement the above results taking into account a particular choice for f(Q), and study the resulting late-time cosmological evolution at the background level. To begin with, we introduce the f(Q) gravity model, which plays a central role in this work: where Λ is the cosmological constant, and b and n are real dimensionless parameters. This model is inspired in that studied in Refs. [47, 48, 49], but in the context of f(R) gravity. It is evident that for b = 0 the model given by Eq. (23) is equivalent to GR plus the cosmological constant. In particular, from the structure of this model, it can be seen as a perturbative deviation from the ΛCDM Lagrangian. In this sense, this model can be arbitrarily close to ΛCDM, depending on the parameter b. It should be highlighted that in the literature also other exponential f(Q) gravity models have been intensively studied (see e.g., Refs. [18, 24, 25, 26, 31, 32, 33, 36]). Following the procedure carried out in Ref. [50], we rewrite Eq. (13) in terms of N = ln a Now, replacing Eqs. (29) and (30) in Eq. (28), and using Eq. (27), we obtain an approximate solution for the Hubble parameter H(z): similarly, the deceleration parameter q is given by where the prime denotes differentiation with respect to z. Using Eqs. (19) and (31) and considering up to second order expansion in b, we obtain approximated analytical expressions for the above parameters in terms of the redshift z, as follows: and Notice that, as it would have been expected, the terms independent of b in each one of the last expressions correspond to those associate to ΛCDM model. With Eqs. (36)-(39), we can plot the evolution of each parameter in terms of the redshift z. Additionally, in order to compare the results with the ΛCDM model, we have also incorporated in the corresponding plots the behavior associated with each quantity defined by Eqs. (32)-(35), but using Eq. (27) instead of (31). In general, from above we can deduce that as the magnitude of b increases, the present model deviates from ΛCDM model. This behavior is the expected, since by construction our approximated solution for H(z) is built as a perturbation of the ΛCDM model solution

Cosmological dynamics and observational constraints: Cosmological dynamics in late-time

মহাজাগতিক গতিবিদ্যা এবং পর্যবেক্ষণের সীমাবদ্ধতা: শেষ সময়ে মহাজাগতিক গতিবিদ্যা

Kosmologische Dynamik und Beobachtungsbeschränkungen: Kosmologische Dynamik in der Spätzeit

Dinámica cosmológica y limitaciones de observación: dinámica cosmológica en tiempos tardíos

Dynamique cosmologique et contraintes d'observation : dynamique cosmologique à la fin des temps

ब्रह्माण्ड संबंधी गतिशीलता और अवलोकन संबंधी बाधाएँ: परवर्ती समय में ब्रह्माण्ड संबंधी गतिशीलता

宇宙論的ダイナミクスと観測的制約: 後期宇宙論的ダイナミクス

우주론적 역학과 관측적 제약: 후기 우주론적 역학

Dinâmica cosmológica e restrições observacionais: Dinâmica cosmológica em tempos tardios

Космологическая динамика и ограничения наблюдений: Космологическая динамика в последнее время

Kozmolojik dinamikler ve gözlemsel kısıtlamalar: Geç zamandaki kozmolojik dinamikler

Động lực vũ trụ và các ràng buộc quan sát: Động lực vũ trụ trong thời gian muộn

宇宙动力学与观测约束：晚期宇宙动力学

This paper is available on arxiv under CC 4.0 license.
Authors:
(1) A. Oliveros, Programa de F´ısica, Universidad del Atl´antico;
(2) Mario A. Acero, Programa de F´ısica, Universidad del Atl´antico. Table of Links Abstract and Intro
The f(Q) gravity: a brief review
Cosmological dynamics in late-time
Parameter constraints
Conclusions
Acknowledgments and References Abstract Keywords: Modified gravity, Dark energy, f(Q) gravity, parameter constraints. PACS: 04.50.Kd, 98.80.-k 1. Introduction For over two decades, significant efforts have been dedicated to cosmological research in pursuit of an explanation of the observed late-time cosmic acceleration. The primary avenue of investigation involves the introduction of a novel energy component within the Universe, termed dark energy (DE), which is distinguished by its negative pressure. Nevertheless, as of the present time, a definitive and satisfactory resolution to the enigma of DE remains elusive; its incorporation into the framework of fundamental physics theories continues to challenge researchers (for a comprehensive review about this topic see Refs. [1, 2, 3]). One of the intriguing approaches for elucidating the late-time cosmic acceleration, beyond the inclusion of either DE or novel forms of matter to account for this phenomenon, lies within the field of modified gravity theories (see e.g. Refs. [4, 5, 6] for a review). Usually, in this framework, the fundamental action is built assuming generalized functions of the scalar curvature (the so-called f(R) theories), general higher-order theories, scalar–tensor theories of gravitation, etc. Recently, a new proposal has emerged within the realm of modified theories of gravitation. These particular theories, in which gravitational interactions are governed by non-metricity, with curvature and torsion being rendered negligible, are known as f(Q) theories or f(Q) symmetric teleparallel gravity, where Q is the non-metricity scalar [7, 8, 9, 10, 11]. These theoretical frameworks hold the potential to provide fresh perspectives on the phenomenon of cosmic acceleration, stemming from the inherent consequences of an alternative geometry as opposed to the conventional Riemannian framework (see Ref. [12] for a recent and extensive review on this topic). Although this proposal is very recent, there are numerous works in the literature that have been carried out using it [13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46]. Usually, owing to the presence of nonlinear elements within the field equations, one of the principal challenges inherent in these scenarios pertains to the task of deriving solutions, whether through analytical or numerical means. Although, commonly the field equations are solved numerically, it is also an usual try to propose a parametrization of either the Hubble parameter, the equation state parameter or f(Q) in terms of the redshift, among other strategies. For instance, in Ref. [13] the authors performed an observational analysis of several modified f(Q) models using the redshift approach, where the f(Q) Lagrangian is reformulated as an explicit function of the redshift, f(z). Various different polynomial parameterizations of f(z) are proposed, including new terms which would allow for deviations from the ΛCDM model. In Ref. [27] a new parametrization of the Hubble parameter is proposed in a model-independent way and apply it to the Friedmann equations in the FLRW Universe. Also, the authors of Ref. [38] implemented a parametrization scheme for the Hubble parameter, obtaining an exact solution for the field equations in f(Q) cosmology. This paper is available on arxiv under CC 4.0 license. Authors: (1) A. Oliveros, Programa de F´ısica, Universidad del Atl´antico; (2) Mario A. Acero, Programa de F´ısica, Universidad del Atl´antico. This paper is available on arxiv under CC 4.0 license. Authors: Authors: (1) A. Oliveros, Programa de F´ısica, Universidad del Atl´antico; (2) Mario A. Acero, Programa de F´ısica, Universidad del Atl´antico. Table of Links Abstract and Intro The f(Q) gravity: a brief review Cosmological dynamics in late-time Parameter constraints Conclusions Acknowledgments and References Abstract and Intro Abstract and Intro The f(Q) gravity: a brief review The f(Q) gravity: a brief review Cosmological dynamics in late-time Cosmological dynamics in late-time Parameter constraints Parameter constraints Conclusions Conclusions Acknowledgments and References Acknowledgments and References Abstract Keywords : Modified gravity, Dark energy, f(Q) gravity, parameter constraints. Keywords PACS : 04.50.Kd, 98.80.-k PACS 1. Introduction For over two decades, significant efforts have been dedicated to cosmological research in pursuit of an explanation of the observed late-time cosmic acceleration. The primary avenue of investigation involves the introduction of a novel energy component within the Universe, termed dark energy (DE), which is distinguished by its negative pressure. Nevertheless, as of the present time, a definitive and satisfactory resolution to the enigma of DE remains elusive; its incorporation into the framework of fundamental physics theories continues to challenge researchers (for a comprehensive review about this topic see Refs. [1, 2, 3]). One of the intriguing approaches for elucidating the late-time cosmic acceleration, beyond the inclusion of either DE or novel forms of matter to account for this phenomenon, lies within the field of modified gravity theories (see e.g. Refs. [4, 5, 6] for a review). Usually, in this framework, the fundamental action is built assuming generalized functions of the scalar curvature (the so-called f(R) theories), general higher-order theories, scalar–tensor theories of gravitation, etc. Recently, a new proposal has emerged within the realm of modified theories of gravitation. These particular theories, in which gravitational interactions are governed by non-metricity, with curvature and torsion being rendered negligible, are known as f(Q) theories or f(Q) symmetric teleparallel gravity, where Q is the non-metricity scalar [7, 8, 9, 10, 11]. These theoretical frameworks hold the potential to provide fresh perspectives on the phenomenon of cosmic acceleration, stemming from the inherent consequences of an alternative geometry as opposed to the conventional Riemannian framework (see Ref. [12] for a recent and extensive review on this topic). Although this proposal is very recent, there are numerous works in the literature that have been carried out using it [13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46]. Usually, owing to the presence of nonlinear elements within the field equations, one of the principal challenges inherent in these scenarios pertains to the task of deriving solutions, whether through analytical or numerical means. Although, commonly the field equations are solved numerically, it is also an usual try to propose a parametrization of either the Hubble parameter, the equation state parameter or f(Q) in terms of the redshift, among other strategies. For instance, in Ref. [13] the authors performed an observational analysis of several modified f(Q) models using the redshift approach, where the f(Q) Lagrangian is reformulated as an explicit function of the redshift, f(z). Various different polynomial parameterizations of f(z) are proposed, including new terms which would allow for deviations from the ΛCDM model. In Ref. [27] a new parametrization of the Hubble parameter is proposed in a model-independent way and apply it to the Friedmann equations in the FLRW Universe. Also, the authors of Ref. [38] implemented a parametrization scheme for the Hubble parameter, obtaining an exact solution for the field equations in f(Q) cosmology.

Cosmological dynamics and observational constraints: Abstract and Intro

মহাজাগতিক গতিবিদ্যা এবং পর্যবেক্ষণের সীমাবদ্ধতা: বিমূর্ত এবং ভূমিকা

Kosmologische Dynamik und Beobachtungsbeschränkungen: Zusammenfassung und Einführung

Dinámica cosmológica y limitaciones de observación: resumen e introducción

Dynamique cosmologique et contraintes d'observation : résumé et introduction

ब्रह्माण्ड संबंधी गतिशीलता और अवलोकन संबंधी बाधाएं: सार और परिचय

宇宙論的ダイナミクスと観測的制約: 概要と序論

우주론적 역학과 관측 제약: 개요 및 소개

Dinâmica cosmológica e restrições observacionais: Resumo e introdução

Космологическая динамика и ограничения наблюдений: Аннотация и введение

Kozmolojik dinamikler ve gözlemsel kısıtlamalar: Özet ve Giriş

Động lực vũ trụ và các ràng buộc quan sát: Tóm tắt và Giới thiệu

宇宙动力学和观测约束：摘要和简介

This paper is available on arxiv under CC 4.0 license.
Authors:
(1) HARRISON WINCH, Department of Astronomy & Astrophysics, University of Toronto and Dunlap Institute for Astronomy and Astrophysics, University of Toronto;
(2) RENEE´ HLOZEK, Department of Astronomy & Astrophysics, University of Toronto and Dunlap Institute for Astronomy and Astrophysics, University of Toronto;
(3) DAVID J. E. MARSH, Theoretical Particle Physics and Cosmology, King’s College London;
(4) DANIEL GRIN, Haverford College;
(5) KEIR K. ROGERS, Dunlap Institute for Astronomy and Astrophysics, University of Toronto. Table of Links Abstract and Intro
Methods
Phenomenology
Discussion and Future Work
Conclusion
Acknowledgments and References 4. DISCUSSION AND FUTURE WORK Although comparison to LSS likelihoods from galaxy surveys, and CMB likelihoods for the lensing, temperature, and polarization power spectra are the most straightforward, the tightest current constraints on axions come from measurements of the Ly-α forest, as these are able to probe the MPS at much smaller scales than either galaxy surveys or the CMB (Rogers & Peiris 2021). However, comparing MPS predictions for extreme axions to data from the Ly-α forest is more difficult, as it requires hydrodynamical simulations of the small-scale nonlinear structure, which in principle could depend on the nonlinear behaviour of the extreme axion model. In this paper, we used the estimates of the linear MPS from the Ly-α forest data, which assumed CDM for the small-scale structure evolution, but this method is only valid in the lowaxion-density regime, where CDM makes up most of the dark matter. Some work has been done modeling the nonlinear Ly-α forest for extreme axions(Leong et al. 2019), but this simulation is computationally expensive. Ideally, the best approach would be to train an emulator to produce extreme axion predictions of the Ly-α data, similar to what was done in Rogers & Peiris (2021). When combined with our modified axionCAMB, this could allow for rapid computation and direct comparison to Ly-α forest data, which would give the most informative constraints on the small-scale behaviour of these extreme axion models. In addition, direct comparison to Ly-α observables would allow us to use higher resolution spectroscopic surveys, such as those done with Keck or VLT Lu et al. (1996); Irsiˇ c et al. ˇ (2017b). Accurate simultaneous constraints on the axion mass, density fraction, and starting angle, would quantitatively address an important question that, so far, has only been approached qualitatively: namely, the required degree of fine-tuning for these extreme axion models to work. Figure 10 shows that a good agreement with data can be reached with axion starting angles that are close to the peak, seperated by less than 10%. Arvanitaki et al. (2020) have proposed a model that could drive the axion field to start near the peak at extremely early times, but the plausibility of these models would depend on exactly how much fine tuning is required. This required degree of fine-tuning depends on the axion mass and density fraction, as seen in Figures 9, 10, and 11, and could also depend on other cosmological parameters. With our modified axionCAMB, we could create estimates of the necessary degree of fine-tuning for a range of axion and cosmological parameters, helping to inform the plausibility of these models that produce starting angles close to π. Another area worth exploring is comparing these constraints to forecast sensitivities by future CMB experiments, such as the Simons Observatory, and CMB-S4 (Hlozek et al. ˇ 2017; Lee et al. 2019; Dvorkin et al. 2022; Abazajian et al. 2022). Although Planck is already cosmic-variance limited for temperature at low-ℓ, there may be substantial improvements to be made with an experiment with better polarization and/or high-ℓ data (Aghanim et al. 2016). CMB lensing also offers the ability to probe the DM MPS at a range of scales(Rogers et al. 2023). We could also experiment with simultaneous constraints from CMB and MPS sources. Direct probes of the MPS can also be used to constrain the extreme axion model, including the Dark Energy Survey (which we used to constrain the vanilla axion model in Dentler et al. 2022), Euclid (Amendola et al. 2018), JWST (Parashari & Laha 2023), and the Vera Rubin Observatory (Mao et al. 2022). Lastly, we could try constraining potentials beyond just the standard cosine shape. Models have been proposed with axions possessing quartic, hyperbolic cosine, or monodromic potentials (Cembranos et al. 2018; Urena L ˜ opez ´ 2019;Jaeckel et al. 2017). In addition, axion-like scalar fields with a variety of potentials have been proposed as an early dark energy component potentially capable of relieving the Hubble tension (Kamionkowski & Riess 2022; Poulin et al. 2023). Axion perturbations in all of these potentials could conceivably be modeled using our modified axionCAMB, since the potential function is implemented generically. The only requirement would be that the potential being tested must simplify to a quadratic at small ϕ values, in order for the particle DM approximation to be valid at late times. This paper is available on arxiv under CC 4.0 license. Authors: (1) HARRISON WINCH, Department of Astronomy & Astrophysics, University of Toronto and Dunlap Institute for Astronomy and Astrophysics, University of Toronto; (2) RENEE´ HLOZEK, Department of Astronomy & Astrophysics, University of Toronto and Dunlap Institute for Astronomy and Astrophysics, University of Toronto; (3) DAVID J. E. MARSH, Theoretical Particle Physics and Cosmology, King’s College London; (4) DANIEL GRIN, Haverford College; (5) KEIR K. ROGERS, Dunlap Institute for Astronomy and Astrophysics, University of Toronto. This paper is available on arxiv under CC 4.0 license. Authors: Authors: (1) HARRISON WINCH, Department of Astronomy & Astrophysics, University of Toronto and Dunlap Institute for Astronomy and Astrophysics, University of Toronto; (2) RENEE´ HLOZEK, Department of Astronomy & Astrophysics, University of Toronto and Dunlap Institute for Astronomy and Astrophysics, University of Toronto; (3) DAVID J. E. MARSH, Theoretical Particle Physics and Cosmology, King’s College London; (4) DANIEL GRIN, Haverford College; (5) KEIR K. ROGERS, Dunlap Institute for Astronomy and Astrophysics, University of Toronto. Table of Links Abstract and Intro Methods Phenomenology Discussion and Future Work Conclusion Acknowledgments and References Abstract and Intro Abstract and Intro Methods Methods Phenomenology Phenomenology Discussion and Future Work Discussion and Future Work Conclusion Conclusion Acknowledgments and References Acknowledgments and References 4. DISCUSSION AND FUTURE WORK Although comparison to LSS likelihoods from galaxy surveys, and CMB likelihoods for the lensing, temperature, and polarization power spectra are the most straightforward, the tightest current constraints on axions come from measurements of the Ly-α forest, as these are able to probe the MPS at much smaller scales than either galaxy surveys or the CMB (Rogers & Peiris 2021). However, comparing MPS predictions for extreme axions to data from the Ly-α forest is more difficult, as it requires hydrodynamical simulations of the small-scale nonlinear structure, which in principle could depend on the nonlinear behaviour of the extreme axion model. In this paper, we used the estimates of the linear MPS from the Ly-α forest data, which assumed CDM for the small-scale structure evolution, but this method is only valid in the lowaxion-density regime, where CDM makes up most of the dark matter. Some work has been done modeling the nonlinear Ly-α forest for extreme axions(Leong et al. 2019), but this simulation is computationally expensive. Ideally, the best approach would be to train an emulator to produce extreme axion predictions of the Ly-α data, similar to what was done in Rogers & Peiris (2021). When combined with our modified axionCAMB, this could allow for rapid computation and direct comparison to Ly-α forest data, which would give the most informative constraints on the small-scale behaviour of these extreme axion models. In addition, direct comparison to Ly-α observables would allow us to use higher resolution spectroscopic surveys, such as those done with Keck or VLT Lu et al. (1996); Irsiˇ c et al. ˇ (2017b). Accurate simultaneous constraints on the axion mass, density fraction, and starting angle, would quantitatively address an important question that, so far, has only been approached qualitatively: namely, the required degree of fine-tuning for these extreme axion models to work. Figure 10 shows that a good agreement with data can be reached with axion starting angles that are close to the peak, seperated by less than 10%. Arvanitaki et al. (2020) have proposed a model that could drive the axion field to start near the peak at extremely early times, but the plausibility of these models would depend on exactly how much fine tuning is required. This required degree of fine-tuning depends on the axion mass and density fraction, as seen in Figures 9, 10, and 11, and could also depend on other cosmological parameters. With our modified axionCAMB, we could create estimates of the necessary degree of fine-tuning for a range of axion and cosmological parameters, helping to inform the plausibility of these models that produce starting angles close to π. Another area worth exploring is comparing these constraints to forecast sensitivities by future CMB experiments, such as the Simons Observatory, and CMB-S4 (Hlozek et al. ˇ 2017; Lee et al. 2019; Dvorkin et al. 2022; Abazajian et al. 2022). Although Planck is already cosmic-variance limited for temperature at low-ℓ, there may be substantial improvements to be made with an experiment with better polarization and/or high-ℓ data (Aghanim et al. 2016). CMB lensing also offers the ability to probe the DM MPS at a range of scales(Rogers et al. 2023). We could also experiment with simultaneous constraints from CMB and MPS sources. Direct probes of the MPS can also be used to constrain the extreme axion model, including the Dark Energy Survey (which we used to constrain the vanilla axion model in Dentler et al. 2022), Euclid (Amendola et al. 2018), JWST (Parashari & Laha 2023), and the Vera Rubin Observatory (Mao et al. 2022). Lastly, we could try constraining potentials beyond just the standard cosine shape. Models have been proposed with axions possessing quartic, hyperbolic cosine, or monodromic potentials (Cembranos et al. 2018; Urena L ˜ opez ´ 2019;Jaeckel et al. 2017). In addition, axion-like scalar fields with a variety of potentials have been proposed as an early dark energy component potentially capable of relieving the Hubble tension (Kamionkowski & Riess 2022; Poulin et al. 2023). Axion perturbations in all of these potentials could conceivably be modeled using our modified axionCAMB, since the potential function is implemented generically. The only requirement would be that the potential being tested must simplify to a quadratic at small ϕ values, in order for the particle DM approximation to be valid at late times.

Extreme Axions Unveiled: Discussion and Future Work

চরম অক্ষরেখা উন্মোচন: আলোচনা এবং ভবিষ্যত কাজ

Extreme Axionen enthüllt: Diskussion und zukünftige Arbeiten

Extreme Axions revelados: discusión y trabajo futuro

Extreme Axions dévoilé : discussion et travaux futurs

एक्सट्रीम एक्सियंस का अनावरण: चर्चा और भविष्य का कार्य

極限アクシオンの解明：議論と今後の取り組み

Extreme Axions 공개: 토론 및 향후 작업

Extreme Axions revelados: discussão e trabalho futuro

Представлены экстремальные аксионы: обсуждение и будущая работа

Extreme Axions Açıklandı: Tartışma ve Gelecekteki Çalışmalar

Extreme Axions được tiết lộ: Thảo luận và công việc trong tương lai

揭开极端轴子的面纱：讨论和未来工作

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