Finite time measurements by Unruh-DeWitt detector and Landauer's principle

TL;DR

This paper investigates finite-time measurements using an Unruh-DeWitt detector, analyzing corrections, thermalization effects, and Landauer's principle implications for information processing in quantum thermodynamics.

Contribution

It introduces a systematic method for computing finite-time corrections and explores nonperturbative effects like thermalization in the context of quantum measurements.

Findings

Finite-time corrections affect detector level distributions.

Adiabatic switching leaves non-vanishing corrections.

Landauer's bound constrains work in finite-time quantum measurements.

Abstract

The model of Unruh-DeWitt detector coupled to the scalar field for finite time is studied. A systematic way of computing finite time corrections in various cases is suggested and nonperturbative effects like thermalization are discussed. It is shown in particular that adiabatic switching off the coupling between the detector and the thermal bath leaves non-vanishing corrections to the detector's levels distribution. Considering the two level detector as an information bearing degree of freedom encoding one bit of information, limits on external work for the detector's (de)couling in finite time following from the Landauer's bound are formulated.