REVIEW
Reexamination of scaling in the five-dimensional Ising model
Statistical Mechanics · Submitted 3 Mar 2006 · 11 references
Pith's verdict: Magnetization confirmation is solid; the new susceptibility claim is not supported by the data as presented.
T0 · AI review
Why Pith says this
Highlight any text to comment on it.
Referee report
The paper
The paper claims
In the 5D Ising model, scaling exponents shift with the path to the critical point.
The reading
What carries the argument
The load-bearing object is the scaling variable $A = L^{2}(T-T_c)/T_c$, which fixes the line in the $(T-T_c,\,1/L^{2})$ plane along which the system size is changed. The argument is that log-log plots of $\langle |M| \rangle$ and of the susceptibility $\chi = \langle M^{2}\rangle - \langle M\rangle^{2}$ against $L$ at fixed $A$ have slopes that depend on the sign of $A$, and the paper reads those slopes as the effective finite-size exponents. The ratio of the susceptibility above $T_c$ to that below $T_c$ is also used to show that the standard expectation of a constant ratio fails as $|T-T_c|$ grows.
Extended reading notes
Core claim
The central finding is that in five dimensions, at the critical coupling $K_c = 0.113915$ used in the paper, the apparent critical exponents of a finite lattice change when the critical point is approached along lines of constant $A = L^{2}(T-T_c)/T_c$ with $A = -1$ ($T < T_c$), $A = 0$ ($T = T_c$), and $A = +1$ ($T > T_c$). For the magnetization the fitted log-log slopes are $-1$, $-5/4$ and $-3/2$ respectively, and for the susceptibility the slopes are $2$, $5/2$ and $2$; the $A = +1$ branch is noted as fitting better to $2$ than to the value $3$ expected from naive doubling. This is presented as a confirmation of the predicted path-dependent scaling and as an extension of earlier magnetization-only results to the susceptibility. The paper notes that the susceptibility data above $T_c$ are problematic, so the $A = +1$ susceptibility result is the least certain part of the claim.
Load-bearing premise
The results assume that after discarding the first half of the 500,000 Monte Carlo sweeps the measured magnetization and susceptibility are equilibrated, and that lattices of size 10 to 31 already show the asymptotic power-law behavior, so the fitted slopes are the true exponents.
Editorial extensions
If this is right
- Finite-size scaling exponents reported for the five-dimensional Ising model must be accompanied by the approach path, since different constant-$A$ lines give different slopes.
- The susceptibility follows the same path dependence as the magnetization, with slopes roughly double for the lower and critical branches, so scaling relations that tie the susceptibility to the magnetization hold along a fixed path.
- The above-$T_c$ branch deviates from the naive doubling expectation, with a fitted slope near $2$ rather than $3$, so the susceptibility above the critical temperature needs its own scaling description.
- Simulations above the upper critical dimension that quote a single set of critical exponents are comparing quantities measured along different paths unless the path is fixed.
Reading between the lines
- The same constant-$A$ analysis could be applied to the high-dimensional percolation problem mentioned in the introduction; the paper motivates that check but does not perform it.
- If the path dependence is asymptotic rather than a finite-size artifact, published high-dimensional exponents that do not specify the path may need to be re-read with the path in mind.
- A direct extension would be to measure the fourth-order cumulant of the magnetization along the same three constant-$A$ lines, since the theory that motivated this study concerned that quantity while this paper reports only magnetization and susceptibility.
Original abstract
In three dimensions, or more generally, below the upper critical dimension, scaling laws for critical phenomena seem well understood, for both infinite and for finite systems. Above the upper critical dimension of four, finite-size scaling is more difficult. Chen and Dohm predicted deviation in the universality of the Binder cumulants for three dimensions and more for the Ising model. This deviation occurs if the critical point T = Tc is approached along lines of constant A = L*L*(T-Tc)/Tc, then different exponents a function of system size L are found depending on whether this constant A is taken as positive, zero, or negative. This effect was confirmed by Monte Carlo simulations with Glauber and Creutz kinetics. Because of the importance of this effect and the unclear situation in the analogous percolation problem, we here reexamine the five-dimensional Glauber kinetics.
The compiled record
The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
The abstract, sentence by sentence
In three dimensions, or more generally, below the upper critical dimension, scaling laws for critical phenomena seem well understood, for both infinite and for finite systems. Above the upper critical dimension of four, finite-size scaling is more difficult. Chen and Dohm predicted deviation in the universality of the Binder cumulants for three dimensions and more for the Ising model. This deviation occurs if the critical point T = Tc is approached along lines of constant A = L*L*(T-Tc)/Tc, then different exponents a function of system size L are found depending on whether this constant A is taken as positive, zero, or negative. This effect was confirmed by Monte Carlo simulations with Glauber and Creutz kinetics. Because of the importance of this effect and the unclear situation in the analogous percolation problem, we here reexamine the five-dimensional Glauber kinetics.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | In three dimensions, or more generally, below the upper critical dimension, scaling laws for critical phenomena seem well understood, for both infinite and for finite systems. | background 1.00 | 0.04 | 0.02 | hedged possibility 0.75 |
| s1 | Above the upper critical dimension of four, finite-size scaling is more difficult. | background 0.96 | 0.04 | 0.03 | asserted 0.93 |
| s2 | Chen and Dohm predicted deviation in the universality of the Binder cumulants for three dimensions and more for the Ising model. | background 1.00 | 0.03 | 0.07 | asserted 0.98 |
| s3 | This deviation occurs if the critical point T = Tc is approached along lines of constant A = L*L*(T-Tc)/Tc, then different exponents a function of system size L are found depending on whether this constant A is taken as positive, zero, or negative. | background 0.92 | 0.08 | 0.12 | asserted 0.94 |
| s4 | This effect was confirmed by Monte Carlo simulations with Glauber and Creutz kinetics. | background 0.91 | 0.11 | 0.05 | asserted 1.00 |
| s5 | Because of the importance of this effect and the unclear situation in the analogous percolation problem, we here reexamine the five-dimensional Glauber kinetics. | contribution 0.91 | 0.33 | 0.05 | asserted 0.77 |
What was examined, and what was not
- arXiv listing abstract v1
- full text
- figures and tables
- references and citing sentences
- relations to other papers
- P abstract
- S sections
- T body sentences
- C citations
- R cross-paper relations
Figures
Figures reproduced from arXiv:cond-mat/0603087 by the authors.
References
How the literature uses it
1 arXiv paper cite this in 1 sentence
Papers citing it
Cites it as background 1 paper
-
For $d ≥4$, also the finite-size-scaling theory and the confluent corrections to scaling have been debated [ref] .
Triviality problem and the high-temperature expansions of the higher susceptibilities for the Ising and the scalar field models on four-, five- and six-dimensional lattices · Introduction · 0.85
Discussion
Disagree with the review, or know something it missed? Leave a comment, highlight any passage above to comment on it, or challenge this review formally.