Microcavity Polaritons for Quantum Simulation

Abstract

Quantum simulations are one of the pillars of quantum technologies. These simulations provide insight in fields as varied as high energy physics, many‐body physics, or cosmology to name only a few. Several platforms, ranging from ultracold‐atoms to superconducting circuits through trapped ions have been proposed as quantum simulators. This article reviews recent developments in another well established platform for quantum simulations: polaritons in semiconductor microcavities. These quasiparticles obey a nonlinear Schrödigner equation (NLSE), and their propagation in the medium can be understood in terms of quantum hydrodynamics. As such, they are considered as “fluids of light.” The challenge of quantum simulations is the engineering of configurations in which the potential energy and the nonlinear interactions in the NLSE can be controlled. Here, some landmark experiments with polaritons in microcavities are revisited, how the various properties of these systems may be used in quantum simulations is discussed, and the richness of polariton systems to explore nonequilibrium physics is highlighted.

Dissipative flow equations

“…and our goal is to determine P α L (2) P α . Since η (2) has only matrix elements between states with different values of α, we know that P α [η (2) , L 0 ]P α = 0. Moreover, using Eq.…”

“…We introduce the small parameter ξ proportional to the off-diagonal part of the Lindbladian. We now expand each matrix element as: d nn ( ) =d (0) nn ( ) + ξd (1) nn ( ) + ξ 2 d (2) nn ( ) + . .…”

“…The study of many-body quantum physics has been recently challenged by the appearance of an increasing number of experimental platforms where genuine quantum phenomena take place notwithstanding the presence of an environment and of dissipation. Exciton polaritons [1,2], lossy atomic and molecular gases [3], cavity and circuit QED arrays [4,5], arrays of trapped ions [6] and Rydberg atoms [7], are only few prominent examples of a long list. Whereas the notion of equilibrium has been a fruitful guide to the development of standard manybody physics, these setups are inherently out of equilibrium and their description requires the introduction of a Lindblad master equation that describes in an effective way the weak coupling to a bath under the Markov approximation [8].…”

Dynamics of optical vortices in 2D materials

“…Although sharing certain polaritonic properties with PhPs, the behavior of exciton-polaritons arise from the Gross-Pitaevskii equation and requires extremely low temperatures, in contrast to the PhP vortices that arise from Maxwell's equations and were measured here at room temperature. Recent demonstrations of quantum simulations [54] and analogies of gravity [55] with exciton-polaritons raise intriguing possibilities for similar prospects with PhPs, especially once higher excitation intensities reach the regime where their nonlinear optical response cannot be neglected [56]. It is possible that nonlinear effects had already affected our measurements here (see Fig.…”

Realising and Compressing Quantum Circuits With Quantum Reservoir Computing

“…It is thus in principle compatible with a wide range of experimental platforms, including essentially all platforms currently considered for quantum computing, but with far less stringent requirements on the control of coupling between nodes. For example, let us mention ultracold ions or atoms (arguably the most advanced platform), cavity quantum electrodynamic systems (which enjoy relatively accessible measurement via optics), circuit quantum electrodynamic systems (which can be considered more accessible in setup) [58], or novel platforms such as those based on the internal states of molecules [59], coupled Bose-Einstein condensates [60] and lattices of exciton-polaritons [61]. In some systems, interactions such as the Coulomb interaction are present in addition to tunnelling, which can in principle further enrich the complexity of quantum networks and potentially improve their computing capacity.…”