Questions tagged [non-equilibrium]
337 questions
34
votes
3 answers
Renormalization Group for non-equilibrium
For equilibrium/ground state systems, a (Wilson) renormalization group transformation
produces a series of systems (flow of Hamiltonians/couplings $H_{\Lambda}$ where $\Lambda$ is the cut-off) such that long-wave/asymptotic behaviour of…
Slaviks
- 4,493
23
votes
6 answers
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
Is thermodynamics really never applicable to…
Metric
- 543
20
votes
5 answers
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 technical books.
Joebevo
- 2,291
20
votes
2 answers
What is "Dynamical phase transition"?
What is "Dynamical phase transition"? It is a fancy notion now. But what exactly does it mean? What is the difference between it and the conventional phase transition?
John
- 1,058
- 1
- 7
- 18
18
votes
2 answers
Applications of the Feynman-Vernon Influence Functional
I am looking for a reference where the Feynman-Vernon influence functional was defined and used in the context of relativistic quantum field theory. This functional is one method to describe non-equilibrium dynamics for open systems (e.g. coupled to…
user566
17
votes
5 answers
How does radiation become black-body radiation?
Textbooks treat black body radiation as radiation in thermal equilibrium with its environment (more specifically - with a black body): Planck's formula is essentially derived from the partition function.
\begin{align}
\hat{\rho}&=Z^{-1}e^{-\beta…
Roger V.
- 68,984
16
votes
1 answer
Maximum Principle vs. Minimum Principle in Non-equilibrium Thermodynamics
Prigogine's Min. principle states that in steady-state non-equilibrium systems the entropy generation rate is at a minimum, i.e., a system will seek a steady-state that has min entropy generation. This principle has a well-established proof, but…
Sankaran
- 1,702
16
votes
1 answer
Relation between Langevin and Fokker-Planck for exponentially correlated noise
What is the corresponding Fokker-Planck equation for,
$\frac{df(t)}{dt}=-kf(t)+\zeta(t)$
where, $\zeta(t)$ is random noise? In particular, how will the Fokker-Planck equation look if $\zeta(t)$ is exponentially correlated (or coloured, see this…
nitin
- 475
- 4
- 11
14
votes
4 answers
How quickly should a fluid come to hydrostatic equilibrium?
Let's say I'm holding a one-liter water bottle, full of water, which I then drop.
Before dropping the water bottle, the equilibrium is for there to be a pressure gradient in the water canceling the gravitational force on the water. While the bottle…
Mark Eichenlaub
- 53,961
12
votes
2 answers
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 active motors which may consume energy from the environment to move and exert force on fibers.
All the chemical reactions have…
0x90
- 3,456
12
votes
2 answers
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 function $$\bar Z[j] = \langle Z[j]…
Adam B
- 367
- 2
- 7
12
votes
4 answers
Diffusion coefficient for asymmetric (biased) random walk
I want to obtain a Fokker-Planck like equation by taking the continuous limit of a discrete asymmetric random walk. Let the probability of taking a step to the right be $p$, and the probability of taking a step to the left be $q$, with $p+q=1$. Let…
SarthakC
- 235
- 2
- 9
12
votes
0 answers
Capturing (perturbatively) non-equilibrium field theory effects using "elementary" methods
I am considering a system of two interacting scalar fields: $\psi$, and $\phi$. The Lagrangian is given…
zudumathics
- 231
12
votes
4 answers
Is "equilibrium state" equivalent to "well-defined state variables"?
Follow up to
Intuitively, why is a reversible process one in which the system is always at equilibrium?
and
How slow is a reversible adiabatic expansion of an ideal gas?
Suppose you have a piston with some air in it and you perform a slow,…
Mark Eichenlaub
- 53,961
10
votes
5 answers
How is temperature defined in non-equilibrium?
I see that temperature is defined always in equilibrium. But systems which are not in equilibrium with their environment. How is temperature defined in these cases?
Humans for example, have a body temperature, though they are not in equilibrium with…
veronika
- 2,867