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5 votes
1 answer
174 views

Difficulty with a scaling argument

I am trying to make sense of an argument in this paper, "Fracture strength: Stress concentration, extreme value statistics and the fate of the Weibull distribution". The paper deals with how ...
Smerdjakov's user avatar
9 votes
4 answers
695 views

Is entropy scale-invariant?

The most common definition I’ve heard of entropy in physics is the number of micro-states for a given macro-state. Most examples use the atomic scale as the micro-setting and some kind of simple, ...
NotAGroupTheorist's user avatar
5 votes
1 answer
564 views

Intuition behind power-law scale invariance

I have seen this notion of a scale-invariant power law curve exhibiting the property that $f(cx) = a(cx)^{-k} = c^{-k}f(x)$, and I am confused about how I should be thinking of this as "scale-...
physics_fan_123's user avatar
0 votes
0 answers
65 views

Derivation of the Ising free energy close to a critical point

In "Statistical physics of fields" Mehran Kardar states that the Ising free energy scales with, $$ f(t,h)\sim t^\alpha g_f\left(\frac{h}{t^\Delta}\right), $$ wherein $t=\vert T-T_c\vert/T_c$ ...
bodokaiser's user avatar
16 votes
3 answers
1k views

Why does Critical Points have fluctuations on all scales (Infinite correlation length)?

I have been studying statistical field theory for a while and I still haven't found a physical explanation for this question. Every answer seems to be kind of circular. Basically something like this: &...
P. C. Spaniel's user avatar
7 votes
2 answers
473 views

Is the Landau free energy scale-invariant at the critical point?

My question is different but based on the same quote from Wikipedia as here. According to Wikipedia, In statistical mechanics, scale invariance is a feature of phase transitions. The key ...
SRS's user avatar
  • 27.2k
1 vote
1 answer
271 views

Physical interpretation of power law cluster size distribution in percolation problem

In the site percolation problem, when the occupation probability $p \rightarrow p_c$, where $p_c$ is the critical probability. The characteristic length diverges, and assuming the usual scaling ansatz ...
Akerai's user avatar
  • 1,057
1 vote
0 answers
72 views

Reference: Renormalization Group and scale invariance in statistical mechanics [duplicate]

Can anyone recommend a book/resource that succinctly explains how the Renormalization Group idea is applied in statistical mechanics? I have some background in undergraduate-level statmech, but none ...
14 votes
3 answers
6k views

Why correlation length diverges at critical point?

I want to ask about the behavior near critical point. Let me take an example of ferromagnet. At $T < T_c$, all spins are aligned to the same direction thus it is in the ordered state, scale ...
john's user avatar
  • 327
32 votes
2 answers
5k views

What is the difference between scale invariance and self-similarity?

I always thought that these two terms are some kind of synonyms, meaning that if you have a self-similar or scale invariant system, you can zoom in or out as you like and you will always see the same ...
Dilaton's user avatar
  • 9,691
12 votes
6 answers
3k views

Are the physical laws scale-dependent?

If you read the article "More Is Different", by P.W. Anderson (Science, 4 August 1972), you will find a deep question: are the physical laws dependent of the size of the system under study? As an ...
asanlua's user avatar
  • 600