Measuring non-Markovianity of processes with controllable system-environment interaction

TL;DR

This paper experimentally demonstrates the measurement of non-Markovianity in quantum processes using controllable system-environment interactions, highlighting the feasibility of quantifying quantum memory effects for future quantum technologies.

Contribution

It introduces an experimental method to quantify non-Markovianity in quantum systems via information exchange, using optical fibers and time delays.

Findings

Identified processes with the strongest memory effects.

Validated a measure for quantum non-Markovianity.

Showed feasibility of quantifying quantum memory experimentally.

Abstract

Non-Markovian processes have recently become a central topic in the study of open quantum systems. We realize experimentally non-Markovian decoherence processes of single photons by combining time delay and evolution in a polarization-maintaining optical fiber. The experiment allows the identification of the process with strongest memory effects as well as the determination of a recently proposed measure for the degree of quantum non-Markovianity based on the exchange of information between the open system and its environment. Our results show that an experimental quantification of memory in quantum processes is indeed feasible which could be useful in the development of quantum memory and communication devices.