Misc,

A trace inequality of Ando, Hiai and Okubo and a monotonicity property of the Golden-Thompson inequality

, and .
(2022)cite arxiv:2203.06136.

Abstract

The Golden-Thompson trace inequality which states that $Tr\, e^H+K łeq Tr\, e^H e^K$ has proved to be very useful in quantum statistical mechanics. Golden used it to show that the classical free energy is less than the quantum one. Here we make this G-T inequality more explicit by proving that for some operators, notably the operators of interest in quantum mechanics, $H=\Delta$ or $H= --\Delta +m$ and $K=$ potential, $Tr\, e^H+(1-u)Ke^uK$ is a monotone increasing function of the parameter $u$ for $0u 1$. Our proof utilizes an inequality of Ando, Hiai and Okubo (AHO): $Tr\, X^sY^tX^1-sY^1-t Tr\, XY$ for positive operators X,Y and for $12 s,\,t 1 $ and $s+t 32$. The obvious conjecture that this inequality should hold up to $s+t1$, was proved false by Plevnik. We give a different proof of AHO and also give more counterexamples in the $32, 1$ range. More importantly we show that the inequality conjectured in AHO does indeed hold in this range if $X,Y$ have a certain positivity property -- one which does hold for quantum mechanical operators, thus enabling us to prove our G-T monotonicity theorem.

Tags

Users

  • @gzhou

Comments and Reviews