Continuous measurements in quantum systems

TL;DR

This paper discusses how continuous quantum measurements can be modeled using stochastic Schrödinger equations and master equations, linking microscopic measurement interactions to macroscopic wave-function collapse.

Contribution

It provides a unified framework connecting stochastic Schrödinger equations with the von Neumann collapse via a general measurement model involving an infinite degrees of freedom.

Findings

Derivation of a master equation from a microscopic measurement model

Connection between stochastic Schrödinger equations and wave-function collapse

Description of measurement apparatus as an infinite degrees of freedom system

Abstract

During a continuous measurement, quantum systems can be described by a stochastic Schr\"odinger equation which, in the appropriate limit, reproduces the von Neumann wave-function collapse. The average behavior on the ensemble of all measurement results is described by a master equation obtained from a general model of measurement apparatus consisting of an infinite set of degrees of freedom linearly interacting with the measured system and in contact with a reservoir at high temperature.