Shaping Dynamical Casimir Photons

Diego A R Dalvit,Wilton J M Kort-Kamp

doi:10.3390/universe7060189

Abstract

Temporal modulation of the quantum vacuum through fast motion of a neutral body or fast changes of its optical properties is known to promote virtual into real photons, the so-called dynamical Casimir effect. Empowering modulation protocols with spatial control could enable the shaping of spectral, spatial, spin, and entanglement properties of the emitted photon pairs. Space–time quantum metasurfaces have been proposed as a platform to realize this physics via modulation of their optical properties. Here, we report the mechanical analog of this phenomenon by considering systems in which the lattice structure undergoes modulation in space and in time. We develop a microscopic theory that applies both to moving mirrors with a modulated surface profile and atomic array meta-mirrors with perturbed lattice configuration. Spatiotemporal modulation enables motion-induced generation of co- and cross-polarized photon pairs that feature frequency-linear momentum entanglement as well as vortex photon pairs featuring frequency-angular momentum entanglement. The proposed space–time dynamical Casimir effect can be interpreted as induced dynamical asymmetry in the quantum vacuum.

Highlights

IntroductionCasimir effect (DCE), was originally described as a motion-induced phenomenon [1], but it can occur when any kind of temporal modulation is exerted on the vacuum to promote virtual photons as real photons [2,3,4,5]
The generation of photon pairs out of the quantum vacuum, the so-called dynamicalCasimir effect (DCE), was originally described as a motion-induced phenomenon [1], but it can occur when any kind of temporal modulation is exerted on the vacuum to promote virtual photons as real photons [2,3,4,5]
We recently proposed an analog dynamical Casimir effect based on the concept of space–time quantum metasurfaces [14], in which the optical properties of a quantum metasurface are modulated in space and time and generate dynamicalCasimir effect (DCE) photon pairs with tailored spatial profiles at giant production rates

Summary

Introduction

Casimir effect (DCE), was originally described as a motion-induced phenomenon [1], but it can occur when any kind of temporal modulation is exerted on the vacuum to promote virtual photons as real photons [2,3,4,5]. The physics of motional dynamical Casimir effects offers interesting insights into the interplay between matter and field fluctuations in non-equilibrium systems. Motional DCE ( known as motioninduced or mechanical DCE) is typically described in a “field-centric” approach based on quantum fluctuations of the electromagnetic field supplemented with time-dependent boundary conditions. The two descriptions result in identical predictions for the angular emission profile of DCE photons. This duality between field-centric and matter-centric approaches occurs in equilibrium fluctuation-induced interactions [11]. Microscopic models can be used to study the dissipative counterpart of DCE emission, namely the drag force on the moving mirror as well as the related problem of quantum friction and associated near-field DCE emission of surface polaritons [12,13]

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Discussion

Conclusion