Questions tagged [non-equilibrium]

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Assumption of local thermodynamic equilibrium in fluid dynamics

Moving fluids are generally in a state of non-equilibrium. However, in fluid dynamics, people generally assume a state of local thermodynamic equilibrium and argue that in such a condition, ...
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Does the fluctuations-dissipation theorem hold in active matter for macroscopic physical quantities?

I am trying to understand how the fluctuation–dissipation theorem applies to active matter. I simulated a system with motors which may consume energy from the environment to move and exert force on ...
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2answers
54 views

What is meant by “linear” in non-equilibrium thermodynamics?

I'm trying to learn a bit about non-equilibrium thermodynamics, and am currently reading de Groot and Mazur. In it, there is a quote right in the beginning, talking about the phenomenological ...
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155 views

Book on statistical mechanics (including kinetics) with Maximum Entropy approach

I am looking for a book on statistical mechanics including non-equilibrium and kinetic topics. Specifically following the Maximum Entropy approach of information theory (a la Jaynes). So far I have ...
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38 views

Reference request: Langevin dynamics of particle in high dimensional quenched random potential

I would like to have some reference (either papers or books) for the study of the Langevin dynamics (out of equilibrium, non asymptotically) of a particle $X(t)\in \mathbb{R}^N$ in a quenched random ...
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25 views

Where can I find careful discussions of equilibrium?

I want to know what physical equilibrium is precisely. I'd like to understand dynamical equilibrium vs. static equilibrium, and I'd like to understand approaches to understand non-equilibrium ...
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2answers
115 views

Probability density during equilibration

An ensemble of states $x$ are initially drawn from a non-equilibrium probability density $P_0(x)$. Over time they will evolve towards the equilibrium distribution $P_\mathrm{eq}(x)$. What I want to ...
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1answer
182 views

How to perform stroboscopic measurements for Floquet topological insulators?

Floquet topological insulators (arXiv:1008.1792, arXiv:1211.5623) have attracted much research interests in condensed matter physics. The goal is to realize topological insulators from trivial ...
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2answers
163 views

What rigid body rotation causes rotational viscosity?

According to the book Non-Equilibrium Thermodynamics by S. R. De Groot and P. Mazur page 309, there are some rigid body rotations causing rotational viscosity. What kind of fluid is that? How can this ...
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27 views

Is there a classical correspondence of the entanglement entropy in isolated quantum systems?

For an isolated quantum system, one can study the time evolution of entanglement entropy after a quantum quench (always a pure state), which has a rich behaviour in various different models. However, ...
5
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1answer
214 views

Proof of periodicity of Floquet Green's function

It is claimed in many papers that the two-time Green's function in time periodic Hamiltonian case is periodic in the average time, i.e. \begin{equation} G(t+T,t'+T)=G(t,t') \end{equation} when $H(t+...
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1answer
59 views

How did Carnevale et al. could argue mass in a ballistically aggregating systetm evolves as $t^{2d/(d+2)}$?

I am trying to understand this paper but I am not able to do it. Please help. See the paper here. First of all how could they write collision time $t_0$ as given there?. I am not able to get it even ...
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30 views

What is the BKT transition in non-equilibrium systems?

There is a useful page on the BKT (or KT) transition here which describes the role of vortices in 2d equilibrium systems. I am interested in what happens in 2d non-equilibrium driven-dissipative ...
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26 views

Example of two-dimensional Langevin equation?

I am looking for an example of a langevin-equation with two variables: $\dot{x}=f(x,t)+\omega, x=(x_1,x_2)$. Can anyone suggest one?
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Is thermodynamics only applicable to systems in equilibrium?

So I was going through callen's thermodynamics book and their he says that thermodynamics is only applicable to systems which are in equilibrium and that naturally raised a few questions in my mind ...
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1answer
43 views

Accurate derivation of electron-phonon scattering contribution to metal resistivity

My lecture derived the expression for this contribtuin using the collision integral approach but I missed lot of details. He considers the lowest order correction to distribution function $f=f_0+\...
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0answers
69 views

Fluctuation-Dissipation Theorem in the Keldysh Formalism

In Kamenev's book Field Theory of Non-Equilibrium Systems (he also has lecture notes online here, which contains the relevant statement on pg. 17), he states that the following equation $$G^K(\epsilon)...
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32 views

Derivation of Feynman rules from generating functional for non-eq QFT

I consider Yukawa non-equilibrium theory with interaction $g\bar{\psi}\phi\psi$ with massive fermionic field $\psi$ with mass $m$ and massive scalar field $\phi$ with mass $M$. I would like to ...
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291 views

Textbooks for non-equilibrium quantum field theory

What are good textbooks for non-equilibrium quantum field theory? Please answer by naming quality books and a short description and review about each one that you have personally read or benefited ...
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2answers
761 views

Pumping water from a closed column. Will the column get empty or just circualte?

As a picture is worth a thousand words, here is my problem: It is a closed water column with a bit of air in the top section. If I run the pump and make the water flow from IN to OUT, Will the level ...
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38 views

Non-eq QFT: functional formalism

I am looking for references (papers, books etc.) where I can find pedagogical introduction to non-eq QFT without hamiltonian approach. I mean that an author start from writing down the generating ...
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4k views

What are some of the best books on complex systems and emergence?

I'm rather interested in getting my feet wet at the interface of complex systems and emergence. Can anybody give me references to some good books on these topics? I'm looking for very introductory ...
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49 views

Question about the Markovian property of the velocity of a Brownian particle following Langevin equation

I'am now studying Langevin model and Fokker-Planck equation with the lecture notes by Borghini Topics in Nonequilibrium Physics (NB: PDF). On page 92, he talks about the Markovian property of the ...
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42 views

Landau Theory of fluctuations

With respect to chapter 12 in the book Statistical Physics(Part 1) by Landau and Lifshitz, I am currently stuck at the intepretation of Fluctuation theory that Landau provides. In the neighbourhood of ...
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1answer
298 views

Equivalent system in Centre manifold theory

I was studying the centre manifold theory. It says (see Kuznetsov (pdf) page 155, theorem 5.2) that the system on the left side of the picture is topologically equivalent to the one on the right. $ \...
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1answer
36 views

How is heat dissipation rate the product of force and velocity?

Let $q$ be heat dissipation to midium, $F$ be the force to a particle, and $\dot{x}$ is the velocity of it. According to the equation (8) in Seifert 2005, $\dot{q} = F \dot{x}$ holds. How does this ...
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1answer
69 views

Entropy production, local thermodynamic equilibrium and adiabatic process

It is said that for local thermodynamic equilibrium the local entropy production needs to be 0. Now, I am reading the following from the book by de Groot and Mazur "Non-Equilibrium Thermodynamics". ...
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1answer
46 views

Equilibrium and non-equilibrium thermodynamic states?

I have the following two states. I have classified them as equilibrium and non-equilibrium and I am not sure if that is the right category my problem is I need to understand what parameters to look ...
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0answers
18 views

Thermalization and structure formation, starting with a pure state coupled to heat bath

I am looking for tractable quantum mechanical systems which show thermalisation and/or structure formation. One idea is a small quantum system S, e.g. a quantum Heisenberg model in a pure state (the ...
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1answer
44 views

Can spontaneous fluctuations cause instantaneous non-equilibrium?

The fluctuation-dissipation theorem says that the linear response of a given system to an external perturbation is expressed as the fluctuation properties of the system in thermal equilibrium. Does ...
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2answers
156 views

What is the intuition behind the statement that non-equilibrium systems with static disorder are self-averaging?

In this paper(1) by C. De Dominics, he makes the argument that in a dynamical statistical mechanics system, one doesn't need to apply the replica trick and can directly disorder average the generating ...
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1answer
71 views

Does the First law of thermodynamics hold if the final state is NOT in equilibrium?

So we know the first low of thermodynamics holds for isolated systems $$\Delta E = W+Q\tag{1}$$ Now assuming we are in a thermally isolated system such that $(Q=0)$ we obtain $$\Delta E= W\tag{2}$$...
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1answer
876 views

Definition of entropy in nonequilibrium states

Thermodynamical definition of entropy $$S(p)=-\int p\ln p~dx$$ is defined only on equilibrium system. But why can't we use it for non-equilibrium system? Is there a well-accepted definition for it?
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69 views

Detailed Balance Violation and Fokker-Planck Equation

Suppose I have a system with N sites, and each site can be modified (M) or anti-modified (A). Transitions between these two states are in part random, and in part auto-regulated by recruitment of At ...
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27 views

Why are the electrodes in thermodynamic equilibrium for a working solar cell?

I was reading a paper that performed simulation of a solar cell under illuminated conditions. Obviously, in these conditions, the device is out of thermodynamic equilibrium. For example the ...
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1answer
823 views

What's the meaning for the derivatives for temperature and pressure?

If we view the temperature and pressure as the function of time and space, $$T = T(x,y,z,t) \quad ; \quad P = P(x,y,z,t)$$ then what's the meaning for the following derivatives? $$\nabla T \...
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1answer
161 views

Fluctuations in Fluctuation Dissipation theorem

In the derivation of the Fluctuation-Dissipation theorem. We encounter an identity $$ \langle\delta A(t) \delta B(0) \rangle = \langle A(t)B(0)\rangle-\langle A \rangle\langle B\rangle$$ where $$\...
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259 views

Exact solution for non-linear Fokker-Planck equation

I'm searching for exact (analytical) results for FP equation in 2 variables (such as $x$ and $p$ in 1D) with a steady state. Kramer's like (with force due to confining potential, such as harmonic ...
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1answer
360 views

Derivation of open boundary conditions for Non-Equilibrium Green's Function (NEGF)

It is widely claimed that the Non-Equilibrium Green's Function (NEGF) equations for the study of quantum transport have been derived from the many-body perturbation theory (MBPT). Yet the bridge ...
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1answer
169 views

Heat transfer between a common material and a non-thermalizable one?

I've read that some systems cannot reach equilibrium (page 15 of the book Selected Scientific Papers of Sir Rudolf Peierls: With Commentary or R. Peierls, “Zur kinetischen Theorie der Wärmeleitung in ...
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35 views

Why the distribution of Fluctuationg force in brownian motion has gaussian distribution?

I am reading the Zwanzig's book and I have a confusion about the average of the fluctuating force and its distribution. As it says $F(t)$ is a random variable that means it has a probability ...
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52 views

Statistical physics at very large particle number

According to this manuscript http://www.math.lmu.de/~michel/credits/Federica_Pezzotti_phd.pdf it is proposed (e.g. at page 18) that particle correlations between particles can be neglected in the ...
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1answer
638 views

How to pass for Langevin equation to Fokker-Planck equation?

What is the procedure to pass from the description of a phenomenon made by the Langevin equation: $$ \frac{dv}{dt}=-\frac{v}{\tau}+\sqrt{2c}\,\eta $$ to the corresponding description with the Fokker-...
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31 views

Is there a multiscale analysis for field theories?

Consider a (zero dimensional) Gaussian field theory described by the dynamical action $$S = \int_t \tilde{\phi}(t) \left[\partial_t \phi(t) + M(t) \phi(t)\right] - \gamma \tilde{\phi}(t)^2\, .$$ $\...
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1answer
203 views

What is the difference between non-equilibrium and equilibrium phase transitions?

My question is about the distinction between certain kinds of phase transitions. I understand what the difference between first and second order ones are. What is the difference between non ...
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1answer
335 views

Brownian motion and equilibrium

I would like to know if when you consider a system in which you have Brownian motion if it is considered a system in equilibrium or far from equilibrium and why. i.e., is Brownian motion considered as ...
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1answer
59 views

Why does the Boltzmann equation deal with single-particle phase space density?

Why does the Boltzmann equation deal with single-particle phase space density $\rho_{1}(\textbf{r}_1,\textbf{p}_1,t)$ rather than the N-particle phase space density $\rho(\{\textbf{r}_i,\textbf{p}_i,t\...
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2answers
89 views

Book(s) fills the gap from introductory thermo to nonequilibrium thermo/stat mech for self-taught student?

I know this is a big question. But as a graduate student, my research is somehow related to nonequilibrium thermodynamics/statistical mechanics. TBH, I hate how some research treat this subject like a ...
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2answers
939 views

Modern textbook on statistical field theory with an emphasis on applications to non-equilibrium phenomena?

What is a good textbook on statistical field theory, with an emphasis on applications to non-equilibrium phenomena? I am a final-year undergraduate, have already taken introductory classes in ...
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1answer
103 views

Do electrons really diffuse when a temperature gradient is applied?

In many websites and books, it is generally said that the charge carriers, be it electrons or holes, diffuse through the considered material when a temperature gradient is applied. However I have ...