English

Anti Lie-Trotter formula

Functional Analysis 2014-12-30 v1

Abstract

Let AA and BB be positive semidefinite matrices. The limit of the expression Zp:=(Ap/2BpAp/2)1/pZ_p:=(A^{p/2}B^pA^{p/2})^{1/p} as pp tends to 00 is given by the well known Lie-Trotter-Kato formula. A similar formula holds for the limit of Gp:=(Ap#Bp)2/pG_p:=(A^p\,\#\,B^p)^{2/p} as pp tends to 00, where X#YX\,\#\,Y is the geometric mean of XX and YY. In this paper we study the complementary limit of ZpZ_p and GpG_p as pp tends to \infty, with the ultimate goal of finding an explicit formula, which we call the anti Lie-Trotter formula. We show that the limit of ZpZ_p exists and find an explicit formula in a special case. The limit of GpG_p is shown for 2×22\times2 matrices only.

Keywords

Cite

@article{arxiv.1412.7905,
  title  = {Anti Lie-Trotter formula},
  author = {K. M. R. Audenaert and F. Hiai},
  journal= {arXiv preprint arXiv:1412.7905},
  year   = {2014}
}

Comments

26 pages

R2 v1 2026-06-22T07:44:08.170Z