Experimental implementation of fully controlled dephasing dynamics and synthetic spectral densities

TL;DR

This paper demonstrates a fully controllable quantum simulator for dephasing dynamics, enabling the simulation of various decoherence processes and advancing the study of open quantum systems.

Contribution

It introduces an experimental platform that allows arbitrary dephasing control, filling a gap in simulating generic dephasing in quantum systems.

Findings

Achieved full experimental control of dephasing dynamics.

Simulated a qubit coupled to an Ising chain in a transverse field.

Demonstrated simulation of non-positive dynamical maps.

Abstract

Engineering, controlling, and simulating quantum dynamics is a strenuous task. However, these techniques are crucial to develop quantum technologies, preserve quantum properties, and engineer decoherence. Earlier results have demonstrated reservoir engineering, construction of a quantum simulator for Markovian open systems, and controlled transition from Markovian to non-Markovian regime. Dephasing is an ubiquitous mechanism to degrade the performance of quantum computers. However, a fully controllable all-purpose quantum simulator for generic dephasing is still missing. Here we demonstrate full experimental control of dephasing allowing us to implement arbitrary decoherence dynamics of a qubit. As examples, we use a photon to simulate the dynamics of a qubit coupled to an Ising chain in a transverse field and also demonstrate a simulation of non-positive dynamical map. Our platform opens the possibility to simulate dephasing of any physical system and study fundamental questions on open quantum systems.