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Tagged with cosmology degrees-of-freedom
7 questions
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Degrees of freedom in the early universe with MSSM?
As nicely summarized on P4 in On effective degrees of freedom in the early universe here; at high temperatures where all the particles of the Standard Model are present, we have 28 bosonic and 90 ...
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graph relativistic degrees of freedom
I'm trying to graph the relativistic degrees of freedom, which should look like the figure
And I am trying to guide me with this Phys.SE answer: Number $g(T)$ of relativistic degrees of freedom as a ...
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Hadron contribution to effective degrees of freedom in early Universe
In transition from quark-gluon plasma to hadron gas in the early Universe, the value of the effective degrees of freedom $g_{\star}$ decreases abruptly. This seems to me like a sort of decoupling: ...
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Degrees of freedom of neutrinos
In cosmology, in $g_{eff}$, the number of relativistic degrees of freedom, one finds that the contribution of neutrinos is 2 ($\frac{7}{8}\times 2$ more precisely) but what is due this 2 factor to ? ...
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Do photons have six degrees of freedom?
Calculations involving pressure and volume relationships of photon gas during the cosmologic expansion of the universe posit an adiabatic cooling process with a heat capacity ration of 4/3.
This ratio ...
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Number $g(T)$ of relativistic degrees of freedom as a function of temperature $T$
Let us consider the total number of relativistic degrees of freedom $g(T)$ for particle species in our universe:
$$g(T)=\left(\sum_Bg_B\right)+\frac{7}{8}\left(\sum_Fg_F\right)$$
Where the sums are ...
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Degrees of freedom in the early Universe
I am reading Dodelson's textbook on cosmology. On page 66 we find equation 3.26:
$$\rho = \frac{\pi^2}{30}T^4\biggl[\sum_{i=\text{bosons}}g_i+\frac{7}{8}\sum_{i=\text{fermions}}g_i\biggr]\equiv g_\...
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