One parameter generalization of BW inequality and its application to open quantum dynamics

Fuente: arXiv
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Main Authors: Chruściński, Dariusz, Kimura, Gen, Ohno, Hiromichi, Singal, Tanmay
Format: Preprint
Published: 2022
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author Chruściński, Dariusz
Kimura, Gen
Ohno, Hiromichi
Singal, Tanmay
author_facet Chruściński, Dariusz
Kimura, Gen
Ohno, Hiromichi
Singal, Tanmay
contents In this paper, we introduce a one parameter generalization of the famous Böttcher-Wenzel (BW) inequality in terms of a $q$-deformed commutator. For $n \times n$ matrices $A$ and $B$, we consider the inequality \[ \Re\langle[B,A],[B,A]_q\rangle \le c(q) \|A\|^2 \|B\|^2, \] where $\langle A,B \rangle = {\rm tr}(A^*B)$ is the Hilbert-Schmidt inner product, $\|A\|$ is the Frobenius norm, $[A,B] =AB-BA$ is the commutator, and $[A,B]_q =AB-qBA$ is the $q$-deformed commutator. We prove that when $n=2$, or when $A$ is normal with any size $n$, the optimal bound is given by \[ c(q) = \frac{(1+q) +\sqrt{2(1+q^2)}}{2}. \] We conjecture that this is also true for any matrices, and this conjecture is perfectly supported for $n$ up to $15$ by numerical optimization. When $q=1$, this inequality is exactly BW inequality. When $q=0$, this inequality leads the sharp bound for the $r$-function which is recently derived for the application to universal constraints of relaxation rates in open quantum dynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2208_10005
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle One parameter generalization of BW inequality and its application to open quantum dynamics
Chruściński, Dariusz
Kimura, Gen
Ohno, Hiromichi
Singal, Tanmay
Quantum Algebra
Mathematical Physics
15A45
In this paper, we introduce a one parameter generalization of the famous Böttcher-Wenzel (BW) inequality in terms of a $q$-deformed commutator. For $n \times n$ matrices $A$ and $B$, we consider the inequality \[ \Re\langle[B,A],[B,A]_q\rangle \le c(q) \|A\|^2 \|B\|^2, \] where $\langle A,B \rangle = {\rm tr}(A^*B)$ is the Hilbert-Schmidt inner product, $\|A\|$ is the Frobenius norm, $[A,B] =AB-BA$ is the commutator, and $[A,B]_q =AB-qBA$ is the $q$-deformed commutator. We prove that when $n=2$, or when $A$ is normal with any size $n$, the optimal bound is given by \[ c(q) = \frac{(1+q) +\sqrt{2(1+q^2)}}{2}. \] We conjecture that this is also true for any matrices, and this conjecture is perfectly supported for $n$ up to $15$ by numerical optimization. When $q=1$, this inequality is exactly BW inequality. When $q=0$, this inequality leads the sharp bound for the $r$-function which is recently derived for the application to universal constraints of relaxation rates in open quantum dynamics.
title One parameter generalization of BW inequality and its application to open quantum dynamics
topic Quantum Algebra
Mathematical Physics
15A45
url https://arxiv.org/abs/2208.10005