summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorJaron Kent-Dobias <jaron@kent-dobias.com>2021-10-12 16:19:15 +0200
committerJaron Kent-Dobias <jaron@kent-dobias.com>2021-10-12 16:19:15 +0200
commit1b15f980bc16ef3abeb456fe214584f80bff88eb (patch)
tree6d6c9f43502364cf7ae36e3e8f5a7b1dd36fdf15
parentdaeb9363886b4a06e630a698b1cf7f10f43969c0 (diff)
downloadpaper-1b15f980bc16ef3abeb456fe214584f80bff88eb.tar.gz
paper-1b15f980bc16ef3abeb456fe214584f80bff88eb.tar.bz2
paper-1b15f980bc16ef3abeb456fe214584f80bff88eb.zip
Removed appendix.
-rw-r--r--ising_scaling.tex37
1 files changed, 0 insertions, 37 deletions
diff --git a/ising_scaling.tex b/ising_scaling.tex
index e6e559e..2c540e6 100644
--- a/ising_scaling.tex
+++ b/ising_scaling.tex
@@ -778,41 +778,4 @@ The successful smooth description of the Ising free energy produced in part by a
\bibliography{ising_scaling}
-\appendix
-
-\section{Legendre series to power series}
-
-In the work, we examine a series of the form
-\[
- h(\theta)=\left(1-\frac{\theta^2}{\theta_c^2}\right)\sum_{i=0}^\infty h_iP_{2i+1}(\theta/\theta_c),
-\]
-where $P_n$ is the $n$th Legendre polynomial. This form is useful for iteratively fitting the $h_i$, since these polynomials are orthogonal on the domain $[-\theta_c,\theta_c]$, but is not useful for evaluating the convergence of the function. For this a simple power expansion in $\theta$ is better. To make the conversion, first recall that
-\[
- P_n(x)=2^n\sum_{k=0}^n\binom nk\binom{\frac{n+k-1}2}nx^k
-\]
-\[
- \begin{aligned}
- \sum_{i=0}^\infty h_iP_{2i+1}(\theta/\theta_c)
- &=\sum_{i=0}^\infty h_i2^{2i+1}\sum_{k=0}^{2i+1}\frac{\theta^k}{\theta_c^k}\binom{2i+1}k\binom{\frac{2i+k}2}{2i+1} \\
- &=\sum_{k=0}^\infty\theta^k\frac1{\theta_c^k}\sum_{i=(k-1)/2}^\infty h_i2^{2i+1}\binom{2i+1}k\binom{\frac{2i+k}2}{2i+1} \\
- &=\sum_{j=0}^\infty\theta^{2j+1}\frac1{\theta_c^{2j+1}}\sum_{i=j}^\infty h_i2^{2i+1}\binom{2i+1}{2j+1}\binom{\frac{2i+2j+1}2}{2i+1}
- \end{aligned}
-\]
-We saw in our fitting that at higher order the coefficients $h_i$ approached roughly the pattern $h_i/h_{i-1}=-b+m/i$ for positive constants $b$ and $m$. This recurrence relation can be solved to give
-\[
- h_i\simeq\frac{(-1)^i}{i!}b^{i-1}(b-m)h_0\frac{\Gamma(2-\frac mb+i-1)}{\Gamma(2-\frac mb)}
-\]
-\[
- \sum_{i=0}^\infty h_iP_{2i+1}(\theta/\theta_c)
- =\sum_{j=0}^\infty\theta^{2j+1}\frac1{\theta_c^{2j+1}}
- \frac{\Gamma(1+j-m/b)}{\Gamma(1-m/b)\Gamma(1+j)}2^{1+2j}(-b)^jh_0\binom{2j+\frac12}{2j+1}{}_2F_1(2j+\tfrac32,1+j-m/b;1+j;b)
-\]
-If we call this coefficient $H_j$, then
-\[
- h(\theta)=\left(1-\frac{\theta^2}{\theta_c^2}\right)\sum_{i=0}^\infty H_i\theta^{2i+1}
- =\sum_{i=0}^\infty H_i\theta^{2i+1}-\frac1{\theta_c^2}\sum_{i=0}^\infty H_i\theta^{2i+3}
- =\sum_{i=0}^\infty(H_i-H_{i-1}/\theta_c^2)\theta^{2i+1}
-\]
-for $H_{-1}=0$.
-
\end{document}