# Trotter-Kato product formulae in Dixmier ideal

## TL;DR

This paper demonstrates convergence of Trotter-Kato product formulae in Dixmier ideal topology for certain Kato functions, providing error bounds and extending previous results on convergence rates in trace-norm for Gibbs semigroups.

## Contribution

It introduces a general scheme to estimate the rate of convergence of Trotter-Kato product formulae in Dixmier ideal topology, extending prior work on trace-norm convergence for Gibbs semigroups.

## Key findings

- Convergence in Dixmier ideal topology for specific Kato functions.
- Error-bound estimates for convergence rate in this topology.
- Extension of convergence rate results to trace-norm for Gibbs semigroups.

## Abstract

It is shown that for a certain class of the Kato functions the Trotter-Kato product formulae converge in Dixmier ideal C 1,$\infty$ in topology, which is defined by the $\times$ 1,$\infty$-norm. Moreover, the rate of convergence in this topology inherits the error-bound estimate for the corresponding operator-norm convergence. 1 since [24], [14]. Note that a subtle point of this program is the question about the rate of convergence in the corresponding topology. Since the limit of the Trotter-Kato product formula is a strongly continuous semigroup, for the von Neumann-Schatten ideals this topology is the trace-norm $\times$ 1 on the trace-class ideal C 1 (H). In this case the limit is a Gibbs semigroup [25]. For self-adjoint Gibbs semigroups the rate of convergence was estimated for the first time in [7] and [9]. The authors considered the case of the Gibbs-Schr{\"o}dinger semigroups. They scrutinised in these papers a dependence of the rate of convergence for the (exponential) Trotter formula on the smoothness of the potential in the Schr{\"o}dinger generator. The first abstract result in this direction was due to [19]. In this paper a general scheme of lifting the operator-norm rate convergence for the Trotter-Kato product formulae was proposed and advocated for estimation the rate of the trace-norm