Seminar Daniel BURGARTH (Aberystwyth University, UK)

日時

2017年4月25日 16:30-18:00

場所

早稲田大学 西早稲田キャンパス 55号館N棟2階 応物物理会議室

言語

英語

講演題目：　Dynamical Decoupling of Unbounded Hamiltonians

概要

We investigate the possibility to suppress unbounded interactions between a finite dimensional system and an infinite dimensional environment through a fast sequence of unitary kicks on the finite dimensional system. This method, called dynamical decoupling, is known to work for bounded interactions, but physical environments such as bosonic heat baths are usually modeled with unbounded interactions, whence here we initiate a systematic study of dynamical decoupling for unbounded operator. We develop a sufficient decoupling criterion for arbitrary Hamiltonians and a necessary decoupling criterion for semibounded Hamiltonians. We give examples for unbounded Hamiltonians where decoupling works and the limiting evolution as well as the convergence speed can be explicitly computed. We show that decoupling does not always work for unbounded interactions and provide both physically and mathematically motivated examples.

ホームページ