Questions tagged [statistical-mechanics]
The study of large, complicated systems employing statistics and probability theory to extract average properties and to provide a connection between mechanics and thermodynamics.
7,312 questions
2 votes
0 answers
48 views
Operations with the hard sphere potential
In statistical mechanics (in particular I'm interested in applying the Landau Kinetic Equation to a hard spheres gas), it is often useful to get the gradient or the Fourier transform of the ...
0 votes
0 answers
31 views
How are Ehrenfest equation and von Neumann equation related? [closed]
I understand how Ehrenfest is sort of giving a correspondence between classical and quantum whereas von Neumann is more like a quantum mechanical equivalent of Liouvilles equation. But do they share ...
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1 vote
0 answers
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Deriving the Boltzmann equation [closed]
In classical mechanics, the space of states is the cotangent bundle of configuration space. This space of states is also called phase space. In the physical case where phase space represents all ...
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1 vote
0 answers
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Curious about entropy and information theory in Bohmian mechanics
I've been playing around with Bohmian mechanics in electronic systems. I really like the interpretation of particle trajectories in terms of the continuity, Hamilton Jacobi equation and guiding ...
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1 vote
0 answers
23 views
Source recommendation for spin glasses and their relation with SYK model
I want to learn Edwards-Anderson and Sherrington-Kirkpatrick models properly with their calculations (Replica symmetry, phase transition, etc.). I need couple of sources such as books and papers ...
3 votes
1 answer
163 views
Ideal gas equation
While deriving ideal gas equation we assumed the container to be a cuboid and then we took the volume to be $lbh$ where l, b, h are length, breadth, and height respectively. Will the equation still be ...
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1 vote
1 answer
66 views
Phase transition for first moments in the 2D random-bond Ising model
I have a very basic confusion about the 2D random-bond Ising model on a square lattice with Boltzmann weight $$\omega(J_{ij},\sigma_j)=\prod_{ij}(1-p)^{\delta_{J_{ij}=1}} p^{\delta_{J_{ij}=-1}} e^{-\...
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0 votes
1 answer
140 views
Cooling molecules with photons
Let's say there is a group of molecules confined in a box. Because of the molecules, the temperature in the box reaches up to 5000 kelvin. Each molecule in the box has about 1.036 * 10^-19 Joules (...
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0 votes
0 answers
41 views
Maxwell-Juttner distribution and its derivation
I am looking for good notes on the Maxwell-Juttner distribution and its derivation. I stumbled across this post Calculation of Maxwell-Juttner distribution integral but I was unable to find reference ...
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1 vote
2 answers
121 views
What is the mechanism behind the Curie point in ferromagnets?
I just finished up a uni course on magnetism, which mostly made sense, but I've been left with some questions about ferromagnetic behaviour; in particular, I'm not satisfied with my lecturer's ...
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0 votes
1 answer
68 views
What causes the difference in the graphs showing the dependence of a molecule's potential energy on distance?
"The potential curve will have the shape shown in the figure above if the molecules approach each other in plane A along the line connecting their centers". "If the molecules approach ...
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-2 votes
1 answer
116 views
Can ideal gasses achieve negative temperature? [closed]
I wish to know if ideal gasses can achieve negative temperatures and if it has been experimentally achieved in some form or not. The reason I am interested in this is because, for ideal gasses we have ...
- 1,726
2 votes
1 answer
120 views
What does grand potential for $2D$ systems mean?
In $3D$ the grand potential $\Omega = -PV$ has a well-defined physical meaning. But for $2D$ systems what would $\Omega$ actually mean physically? Dimensionally speaking it looks like $\Omega = -\...
- 1,726
2 votes
2 answers
94 views
How to see entropy vanishes for fermionic gas at $T = 0$ from the grand potential?
I want to see the entropy of a Fermi gas vanish at $T=0$ without using the density matrix as some answers have utilized online. The grand potential for fermi gas (Second Eq. in Sec. 9.4 on page 92) is ...
- 1,726
3 votes
0 answers
68 views
Diffusion equation after one time-step [closed]
Consider the equation: $$ \partial_tu=D\partial_{xx}^2u $$ with reflecting boundary condition at $x=0$ and with $u(x,0)=\delta(x)$ as an initial distribution. First question: How should I understand a ...
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