Decoherence and the retrieval of lost information

TL;DR

This paper demonstrates that measuring the environment of an open quantum system can reduce its decoherence rate, revealing new ways to control quantum information preservation through environmental interactions.

Contribution

It introduces a novel concept that environmental measurement can decrease decoherence, supported by an example of indirect qubit measurement and its impact on environmental noise.

Findings

Measurement on environment can reduce decoherence rate

Environmental noise diminishes near the qubit when decoherence is reduced

Quantum interference explains the observed effects

Abstract

We found that in contrast with the common premise, a measurement on the environment of an open quantum system can {\em reduce} its decoherence rate. We demonstrate it by studying an example of indirect qubit's measurement, where the information on its state is hidden in the environment. This information is extracted by a distant device, coupled with the environment. We also show that the reduction of decoherence generated by this device, is accompanied with diminution of the environmental noise in a vicinity of the qubit. An interpretation of these results in terms of quantum interference on large scales is presented.