Primordial 2.7° Radiation as Evidence against Secular Variation of Planck's Constant

Noerdlinger, Peter D.

doi:10.1103/physrevlett.30.761

Cited by 12 publications

(3 citation statements)

References 9 publications

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“…There are many papers in the literature (e.g. [19,20,21,22,23,24,25,26,27,28,29,30,31,32,33]) which try to answer a question such as: "What would happen to observable X, if the speed of light or the gravitational constant or Planck's constant had a different value". Such questions are not well defined, since one can tune the other parameters of the dimensional set P , such that the dimensionless ratios in (1) remain the same.…”

Section: Introductionmentioning

confidence: 99%

Dimensionless cosmology

Narimani

Moss

Scott

2012

Astrophys Space Sci

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Although it is well known that any consideration of the variations of fundamental constants should be restricted to their dimensionless combinations, the literature on variations of the gravitational constant $G$ is entirely dimensionful. To illustrate applications of this to cosmology, we explicitly give a dimensionless version of the parameters of the standard cosmological model, and describe the physics of Big Bang Neucleosynthesis and recombination in a dimensionless manner. The issue that appears to have been missed in many studies is that in cosmology the strength of gravity is bound up in the cosmological equations, and the epoch at which we live is a crucial part of the model. We argue that it is useful to consider the hypothetical situation of communicating with another civilization (with entirely different units), comparing only dimensionless constants, in order to decide if we live in a Universe governed by precisely the same physical laws. In this thought experiment, we would also have to compare epochs, which can be defined by giving the value of any {\it one} of the evolving cosmological parameters. By setting things up carefully in this way one can avoid inconsistent results when considering variable constants, caused by effectively fixing more than one parameter today. We show examples of this effect by considering microwave background anisotropies, being careful to maintain dimensionlessness throughout. We present Fisher matrix calculations to estimate how well the fine structure constants for electromagnetism and gravity can be determined with future microwave background experiments. We highlight how one can be misled by simply adding $G$ to the usual cosmological parameter set

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Section: Introductionmentioning

confidence: 99%

Dimensionless cosmology

Narimani

Moss

Scott

2012

Astrophys Space Sci

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“…This would contradict our usual notions of causality. The first experiment to attempt to distinguish between the two theories was Partridge's (1973). He measured the power input to a microwave source as it alternatively radiated into free space (where very little energy was absorbed locally) and then into an efficient local absorber.…”

Section: Observations For the Far Future -If Evermentioning

confidence: 99%

“…Noerdlinger (1973) has pointed out that if Planck's constant is taken to be potentially variable, the black-body spectrum of the radiation requires the fractional change of he with redshift z to be less than three parts in 10^ since decoupling. This is derived by noting that the temperature of the background derived from the Rayleigh-Jeans part of the spectrum, which does not depend on h, is the same (to within about 30 per cent) as the temperature derived from the turnover of the spectrum, which does depend on h. The main question here, however, is whether one would really expect h to change in principle, since it is a dimensional quantity and its value is really just a convention.…”

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confidence: 99%

Cosmological Information from New Types of Radio Observations

Saslaw

1977

Symp. - Int. Astron. Union

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To have squeezed the Universe into a ballTo roll it toward some overwhelming question.T. S. EliotSo far, we have mainly discussed what might be called classical methods for investigating cosmological models using radio observations. These mostly involve the number counts as a function of measured flux, angular diameters, and spatial distribution of radio sources at cosmological distances, as well as the measurements of the microwave background. In this review, I have been asked to give a brief description of some new, or non-classical, measurements that might be made. It seems that such measurements fall into one of three categories: Observations which are being made now and which may bear fruit in the next several years, observations which may be possible in the intermediate future several decades from now, and observations which may be possible in the far future - if ever. Naturally I'll try to concentrate on the first two categories since they will be of more interest to most living astronomers during their working lifetimes. Also, since time is short and it is very difficult to predict the future, I'm afraid that this review will be somewhat impressionistic rather than exhaustive. I hope people will describe additional methods during the discussion.

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Does Planck’s constant vary versus time?

Julg¹

1998

Lecture Notes in Chemistry

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Primordial 2.7° Radiation as Evidence against Secular Variation of Planck's Constant

Abstract: The blackbody form of the 2.7° cosmic microwave radiation appears to be inconsistent with variation of Planck's constant by as much as 10% since the epoch z ~ 1000.

Cited by 12 publications

References 9 publications

Dimensionless cosmology

Dimensionless cosmology

Cosmological Information from New Types of Radio Observations

Does Planck’s constant vary versus time?

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