Bounding the Frobenius norm of a q-deformed commutator
Abstract
For two complex matrices and , we define the -deformed commutator as for a real parameter . In this paper, we investigate a generalization of the B\"{o}ttcher-Wenzel inequality which gives the sharp upper bound of the (Frobenius) norm of the commutator. In our generalisation, we investigate sharp upper bounds on the -deformed commutator. This generalization can be studied in two different scenarios: firstly bounds for general matrices, and secondly for traceless matrices. For both scenarios, partial answers and conjectures are given for positive and negative . In particular, denoting the Frobenius norm by , when either or is normal, we prove the following inequality to be true and sharp: for positive . Also, we conjecture that the same bound is true for positive when either or is traceless. For negative , we conjecture other sharp upper bounds to be true for the generic scenarios and the scenario when either of or is traceless. All conjectures are supported with numerics and proved for .
Keywords
Cite
@article{arxiv.2202.11520,
title = {Bounding the Frobenius norm of a q-deformed commutator},
author = {Dariusz Chruściński and Gen Kimura and Hiromichi Ohno and Tanmay Singal},
journal= {arXiv preprint arXiv:2202.11520},
year = {2022}
}
Comments
A shortcoming in the earlier proof of Proposition 1 has been remedied. A new and more elementary proof is provided for Proposition 3; the older proof is also retained. 18 pages and 4 figures. All comments are welcome