How to Reconstruct a Varying Speed of Light Signal from Baryon Acoustic Oscillations Surveys

Salzano, Vincenzo

doi:10.3390/universe3020035

Cited by 5 publications

(7 citation statements)

References 18 publications

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“…In VSL models, various cosmological observables are affected by changing c at different epoch. Thus, there have been investigations of effects of variations of fundamental constants including c on various cosmological observables, such as BBN [81,167,[206][207][208][209][210], CMB [43,185,[211][212][213], baryonic acoustic oscillations (BAO) [214][215][216][217][218], SNe [218][219][220], GWs [31,[221][222][223], Hubble parameter [224], strong lensing (SL) [225] , and others [226,244,245].…”

Section: Jcap08(2021)054mentioning

confidence: 99%

The minimally extended Varying Speed of Light (meVSL)

Lee

2021

J. Cosmol. Astropart. Phys.

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Even though there have been various models of the time-varying speed of light (VSL), they remain out of the mainstream because of their possible violation of physics laws built into fundamental physics. In order to be the VSL as a viable theory, it should inherit the success of special relativity including Maxwell equations and thermodynamics at least. For this purpose, we adopt the assumption that the speed of light, c̃, i.e., c̃[a], varies for the scale factor, a. The background FLRW universe can be defined by the constant cosmic time hypersurface using physical quantities such as temperature, density, c̃, etc. It is because they evolve in cosmic time and the homogeneity of the Universe demands that they must equal at the equal cosmic time. The variation of c̃ accompanies the joint variations of all related physical constants in order to satisfy the Lorentz invariance, thermodynamics, Bianchi identity, etc. We dub this VSL model as a “minimally extended VSL (meVSL)”. We derive cosmological observables of meVSL and obtain the constraints on the variation of c̃ by using current cosmological observations. Interestingly, both the cosmological redshift z and all geometrical distances except the luminosity distance of meVSL are the same as those of general relativity. However, the Hubble parameter of meVSL is rescaled as H(z) = (1+z)-b/4 H(GR)(z), where H(GR)(z) denotes the Hubble parameter obtained from general relativity. Thus, it might be used as an alternative solution for the tension of the Hubble parameter measurements. In this manuscript, we provide the main effects of the meVSL model on various cosmological observations including BBN, CMB, SZE, BAO, SNe, GWs, H, SL, and Δα. Compared to previous VSL models, meVSL might provide alternative solutions for various late time problems of the standard ΛCDM model. This is the main motivation for proposing the meVSL model.

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Section: Jcap08(2021)054mentioning

confidence: 99%

The minimally extended Varying Speed of Light (meVSL)

Lee

2021

J. Cosmol. Astropart. Phys.

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“…Recently, there have been interesting investigations of mVSL model effects on cosmological observables, such as CMB [209], BAO [211][212][213][214][215], SNe [216,217], GWs [219],…”

Section: Previous Vslmentioning

confidence: 99%

“…∆A(z 1 ) ≡ (A(z 1 ) − A (GR) (z 1 ))/A (GR) (z 1 ) × 100 % and they are all sub-percentage level for −0.1 ≤ b ≤ 0.1. Thus, even though there do exist the differences in A(z 1 ) between GR and meVSL, they might be ignored with the given measurement accuracy [214].…”

Section: Baomentioning

confidence: 99%

“…In VSL models, various cosmological observables are affected by changing c at different epoch. Thus, there have been investigations of effects of variations of fundamental constants including c on various cosmological observables, such as BBN [78,164,[203][204][205][206][207], CMB [40,182,[208][209][210], baryonic acoustic oscillations (BAO) [211][212][213][214][215], SNe [215][216][217], GWs [28,[218][219][220], Hubble parameter [221], strong lensing (SL) [222] , and others [223][224][225].…”

Section: Introductionmentioning

confidence: 99%

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The minimally extended Varying Speed of Light (meVSL)

Lee

2020

Preprint

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Even though there have been the various varying speed of light (VSL) cosmology models, they remain out of the mainstream because of their possible violation of physics laws built into fundamental physics. In order to be the VSL as a viable theory, it should inherit the success of special relativity including Maxwell equations and thermodynamics at least. Thus, we adopt that the speed of light, c varies for the cosmic time not for the local time, i.e., c[z] where z is the cosmological redshift.When one describes the background FLRW universe, one can define the constanttime hypersurface by using physical quantities such as temperature, density, and c.It is because they evolve in time, and the homogeneity of the Universe demands that they must equal at the equal cosmic time. The variation of c accompanies the joint variations of all related physical constants in order to satisfy the Lorentz invariance, thermodynamics, and Bianchi identity. We call this VSL model as a "minimally extended VSL (meVSL)". We derive cosmological observables of meVSL and obtain the constraints on the variation of c by using the current observations. Interestingly, z and all geometrical distances except the luminosity distance of meVSL are the same as those of general relativity. However, the Hubble parameter of meVSL is rescaled as H = (1 + z) −b/4 H (GR) which might be used as a solution for the tension of the Hubble parameter measurements. In this manuscript, we provide the main effects of meVSL on various cosmological observations including BBN, CMB, SZE, BAO, SNe, GWs, H, SL, and ∆α.

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“…Still, cosmological tests of c variations are much more scarce and less precise. Fortunately, a variety of high-quality observational data obtained from extragalactic surveys are becoming available to test the basic laws in the more distant universe (Salzano et al 2016;Balcerzak et al 2017;Salzano 2017aSalzano , 2017b. Based on a flat Friedmann-Lemaître-Robertson-Walker (FLRW) universe, the simple relationship c(z M ) = D A (z M )H(z M ) between the speed of light c, the angular diameter distance D A (z), and the Hubble parameter H(z) was proposed (Salzano et al 2015), at the redshift z M corresponding to the maximum of D A (z) function.…”

Section: Introductionmentioning

confidence: 99%

Measuring the Speed of Light with Updated Hubble Diagram of High-redshift Standard Candles

Liu

Cao

Biesiada

et al. 2023

ApJ

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The possible time variation of the fundamental constants of nature has been an active subject of research in modern physics. In this paper, we propose a new method to investigate such possible time variation of the speed of light c using the updated Hubble diagram of high-redshift standard candles including Type Ia Supernovae (SNe Ia) and high-redshift quasars (based on UV–X relation). Our findings show that the SNe Ia Pantheon sample, combined with currently available sample of cosmic chronometers, would produce robust constraints on the speed of light at the level of c/c 0 = 1.03 ± 0.03. For the Hubble diagram of UV+X-ray quasars acting as a new type of standard candle, we obtain c/c 0 = 1.19 ± 0.07. Therefore, our results confirm that there is no strong evidence for deviation from a constant speed of light up to z ∼ 2. Moreover, we discuss how our technique might be improved at much higher redshifts (z ∼ 5), focusing on future measurements of the acceleration parameter X(z) with gravitational waves (GWs) produced by binary neutron star mergers. In particular, in the framework of the second-generation space-based GW detector, DECi-hertz Interferometer Gravitational Wave Observatory, the speed of light is expected to be constrained with a precision of Δc/c = 10−3.

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How to Reconstruct a Varying Speed of Light Signal from Baryon Acoustic Oscillations Surveys

Cited by 5 publications

References 18 publications

The minimally extended Varying Speed of Light (meVSL)

The minimally extended Varying Speed of Light (meVSL)

The minimally extended Varying Speed of Light (meVSL)

Measuring the Speed of Light with Updated Hubble Diagram of High-redshift Standard Candles

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