296 reputation
17
bio website blitiri.blogspot.com
location Paris area, France
age
visits member for 1 year, 7 months
seen 25 mins ago

I am a soft matter physicist, working at the CNRS in the Paris area. I blog about physics and other topics.


Sep
24
awarded  Autobiographer
Mar
13
awarded  Yearling
Jan
21
revised Do small-angle coherent scattering experiments really see coherent effects over arbitrarily large distances?
added 600 characters in body
Jan
21
awarded  Revival
Dec
30
comment Transport theorem derivation question
What happened to the derivative of $J$ (which depends explicitly on time)?
Dec
29
revised Distributions (e.g., Dirac Delta): confused and unhappy
deleted 1 characters in body
Dec
28
answered Distributions (e.g., Dirac Delta): confused and unhappy
Dec
21
awarded  Commentator
Dec
21
comment Does coffee with cream cool slower than black coffee?
I do not see how repeating that experiment would answer the question above...
Dec
15
comment Expression of $\kappa_S$ in photon gas
Well, you know $p(T)$, so just invert it. It is even easier to determine the adiabatic index $\gamma$, such that $pV^{\gamma} = Cst$ for constant $S$, because you can obtain $\kappa _S$ without writing down the constants explicitly.
Dec
15
comment Expression of $\kappa_S$ in photon gas
Try substituting in the final result the expression for $S$. You get a much simpler form, which can also be derived directly from the $V=V(p,S)$ (not that difficult, really; try it out!)
Dec
13
comment Why do we get the same result using different ensembles?
Saying "just replace $\bar{N}$ with $N$ in the final result" hides a non-trivial step; it actually means: "impose a chemical potential $\mu$ such that the average number of particles $\bar{N}$ is equal to the value $N$ imposed in the canonical ensemble". In a second step you can invoke the thermodynamic limit, as explained by @Abhinav to show the irrelevance of fluctuations in $N$ (in the grand-canonical ensemble) and in $\mu$ (in the canonical ensemble).
Dec
11
comment Why does this integral come out imaginary?
Since when is $J_0(x)$ odd ?!
Dec
11
comment Using $\frac{1}{A+i\epsilon} = PV\frac{1}{A}-i\pi\delta(A)$ in Feynman Integrals
Are the zeros discrete (in $(x^{\pm},y^{\pm})$) or is $f$ zero along the entire lines $y^{\pm}$ ?! What you wrote looks like the latter...
Dec
10
answered Does quasi-static motion imply zero energy dissipation?
Dec
10
answered FWHM in resonance amplitude square derivation
Dec
10
comment Does quasi-static motion imply zero energy dissipation?
Your thought experiment does not explicitly involve quasi-static motion. Are you maybe thinking of a reversible process?
Dec
10
asked Does coffee with cream cool slower than black coffee?
Dec
8
revised Does the weight of an hourglass change when sands are falling inside?
added 233 characters in body
Dec
5
comment Force exerted by fluid in circular pipe
In the absence of drag and viscosity, I would guess there is no tangential force, see D'Alembert's paradox.