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Question 1

1vote

0answers

68views

Do memory operators create new scaling directions at the Wilson–Fisher fixed point?

Has anyone looked at memory terms in FRG before? I tried adding a simple history-dependent self-energy to the Wetterich flow, and it seems to generate a new relevant scaling direction at the Wilson–...

Riverhax

11

askedAug 20 at 16:53

Question 2

2votes

1answer

296views

Finite Size Scaling and the Gaussian Model

The Gaussian model in momentum space, is given by$$S = \frac{1}{2} \int_k (r + k^2)\phi^2(k) $$The susceptibility is then $\chi(k) = \frac{1}{r + k^2}$. At the critical value $r = 0$, there's a ...

Santa Claus

23

askedAug 13 at 13:58

Question 3

5votes

1answer

199views

What bounds on the possible values of critical exponents can we derive from first principles?

Consider some many-body Hamiltonian $H$- let's say classical for simplicity, e.g. the Ising model - that is parameterized by some "external" parameters $\{h_i\}$, e.g. pressure or applied ...

tparker

52.3k

askedJul 5 at 19:01

Question 4

1vote

1answer

140views

Can the critical exponent $\alpha$ be greater than or equal to 1?

The critical exponent $\alpha$ describes the (non-analytic part of the) behavior of the specific heat capacity $C$ as a function of temperature near a continuous thermal phase transition: $C \sim |T - ...

tparker

52.3k

askedJul 4 at 20:17

Question 5

3votes

0answers

64views

Fluctuations at the critical point: can they reach centimeter scales?

In the wikipedia article on critical opalescence, the following claim appears:As the density fluctuations become of a size comparable to the wavelength of light, the light is scattered and causes ...

Plemath

272

askedJun 26 at 17:15

Question 6

1vote

1answer

155views

When the partition function at $\beta\in[0,1]$ is interesting?

I am not a physicist, so apologies in case I am not formal enough.I wrote an algorithm that computes $e^{-\beta H}$.$H=\sum_k c_k O_k$ is the Hamiltonian for a transverse spin chain.The algorithm ...

Daniele Cuomo

261

askedJun 10 at 12:07

Question 7

3votes

0answers

116views

Is it possible to analytically continue magnetization in one-dimensional Ising models?

I am asking about the infinitely long layered Ising model with a finite number of layers. The model is assumed to be invariant under translations along the direction in which it is infinite. All ...

Gec

7,827

askedMay 20 at 9:03

Question 8

1vote

0answers

248views

How is the general expression for critical exponents established?

The Wikipedia page on the critical exponents of the Ising model presents the following table:This page lists the critical exponents ($\alpha$, $\beta$, $\gamma$, ...) and their values for some ...

Foxy

185

askedMay 14 at 11:03

Question 9

5votes

0answers

207views

Coleman-Weinberg mechanism in $\phi^4$ theories in $d=4$

I'm not versed at all in high energy physics, I come from a statistical mechanics background, hence, all of what follow is far from my comfort zone. I will also talk about what is, I believe, the lore ...

Syrocco

2,855

askedApr 28 at 8:05

Question 10

0votes

0answers

37views

Mean field approximation and critical exponents' scaling relations [duplicate]

Consider a system which exhibits a phase transition at a temperature $T_c$, let $\psi$ be an order parameter, $J$ the corresponding conjugate field ($\langle \psi \rangle = -\partial F/\partial J$) ...

TheFox

77

askedApr 17 at 15:08

Question 11

0votes

1answer

135views

Why the 2D Ising model shows a phase transition while the 1D does not? [duplicate]

I'm reading this article which shows the breakdown of the Mermin-Wagner theorem for a 2D system with finite size. In short, the Mermin-Wagner theorem states that no system with dimensionality d $\leq2$...

samuelmsoares

71

askedApr 17 at 0:20

Question 12

3votes

1answer

159views

Application of the Bogoliubov transformation to the Hamiltonian of the transverse 1D Ising model

I’m having difficulty understanding how to reach the diagonal form of the Hamiltonian for the 1D Ising model under the application of a transverse magnetic field. Following the thesis https://open.fau....

samuelmsoares

71

askedMar 27 at 1:13

Question 13

0votes

0answers

68views

How to Calculate Ground State Scaling Dimension of a Finite Critical System Which is Conformally Invariant?

Suppose I have a 1D finite chain of a critical system (e.g., the quantum Potts model or Ising model). By introducing a conformally invariant boundary condition to the system, specific primary fields ...

Mohammad. Reza. Moghtader

61

askedMar 23 at 18:32

Question 14

1vote

0answers

60views

Truncated convolution in second order computation for the critical exponent $\eta$

This question might be more suited for mathematics stack exchange, but since it's a physics problem. I believe that people here could have the answer.In order to evaluate this diagram: using Wilson ...

Syrocco

2,855

askedMar 19 at 11:12

Question 15

3votes

1answer

235views

How to Calculate Virasoro's Characters of Critical 3-state Pott's model without Considering $W$ algebra?

Let's consider the critical 3-state Potts model. According to conformal field theory, it corresponds to a CFT with a central charge $c=\frac{4}{5}$. However, there are 10 characters for $c=\frac{4}{5}$...

Mohammad. Reza. Moghtader

61

askedFeb 26 at 10:01

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Stack Exchange Network

Questions tagged [critical-phenomena]

Do memory operators create new scaling directions at the Wilson–Fisher fixed point?

Finite Size Scaling and the Gaussian Model

What bounds on the possible values of critical exponents can we derive from first principles?

Can the critical exponent $\alpha$ be greater than or equal to 1?

Fluctuations at the critical point: can they reach centimeter scales?

When the partition function at $\beta\in[0,1]$ is interesting?

Is it possible to analytically continue magnetization in one-dimensional Ising models?

How is the general expression for critical exponents established?

Coleman-Weinberg mechanism in $\phi^4$ theories in $d=4$

Mean field approximation and critical exponents' scaling relations [duplicate]

Why the 2D Ising model shows a phase transition while the 1D does not? [duplicate]

Application of the Bogoliubov transformation to the Hamiltonian of the transverse 1D Ising model

How to Calculate Ground State Scaling Dimension of a Finite Critical System Which is Conformally Invariant?

Truncated convolution in second order computation for the critical exponent $\eta$

How to Calculate Virasoro's Characters of Critical 3-state Pott's model without Considering $W$ algebra?

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