Reply to 'comment on Berry phase in a composite system'

TL;DR

This paper discusses the conditions under which the adiabatic theorem fails in weakly coupled systems and clarifies the proper definition of subsystem geometric phase.

Contribution

It provides a clarification on the validity of the adiabatic theorem and the definition of geometric phase in composite systems under weak coupling.

Findings

Adiabatic theorem breaks down in weak coupling limit.

Subsystem geometric phase is well defined in this regime.

Abstract

In this reply, we show that the adiabatic theorem would break down in the weak coupling limit, and the definition for the subsystem geometric phase is well defined.