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Dec
15
awarded  Favorite Question
Dec
4
asked Is the Electroweak theory chiral regardless of temperature?
Nov
21
comment An argument that massive particles don't redshift?
I accept that comoving observers measure massless photons redshifting. The accepted viewpoint is that comoving observers also measure the momentum of massive particles redshifting. For instance in his GR lecture notes Sean Carroll states that a gas of particles cools down as the Universe expands. In the calculation above I'm questioning whether that latter effect actually does take place. Of course I'm almost certainly wrong.
Nov
21
revised An argument that massive particles don't redshift?
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Nov
21
comment An argument that massive particles don't redshift?
Yes. It seems that as a particle with mass freely moves through expanding space its total energy, as measured by a co-moving observer, $E=\sqrt{m^2+p^2}$, does not change. Thus its momentum/velocity does not change either.
Nov
20
revised An argument that massive particles don't redshift?
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Nov
20
asked An argument that massive particles don't redshift?
Nov
16
comment Does rest mass increase in the FRW metric?
However the FLRW metric does have a conformal timelike Killing vector so that the energy of a co-moving particle, with respect to the metric co-ordinates, increases with the scale factor. This leads to interesting consequences like a Universe with non-zero vacuum energy expanding linearly with cosmological time rather than exponentially.
Nov
16
revised Does rest mass increase in the FRW metric?
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Nov
16
revised Does rest mass increase in the FRW metric?
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Nov
16
revised Does rest mass increase in the FRW metric?
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Nov
16
revised Does rest mass increase in the FRW metric?
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Nov
16
revised Does rest mass increase in the FRW metric?
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Nov
16
revised Does rest mass increase in the FRW metric?
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Nov
16
asked Does rest mass increase in the FRW metric?
Nov
13
revised Definition of Energy in Friedmann equations?
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Nov
13
revised Definition of Energy in Friedmann equations?
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Nov
13
revised Definition of Energy in Friedmann equations?
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Nov
13
asked Definition of Energy in Friedmann equations?
Nov
1
revised Does $g_{\mu\mu}$ in an expression follow the Einstein summation convention?
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