Accelerating Polaritons with External Electric and Magnetic Fields

Abstract

It is widely assumed that photons cannot be manipulated using electric or magnetic fields. Even though hybridization of photons with electronic polarization to form exciton-polaritons has paved the way to a number of ground-breaking experiments in semiconductor microcavities, the neutral bosonic nature of these quasiparticles has severely limited their response to external gauge fields. Here, we demonstrate polariton acceleration by external electric and magnetic fields in the presence of nonperturbative coupling between polaritons and itinerant electrons, leading to formation of new quasiparticles termed polaron-polaritons. We identify the generation of electron density gradients by the applied fields to be primarily responsible for inducing a gradient in polariton energy, which in turn leads to acceleration along a direction determined by the applied fields. Remarkably, we also observe that different polarization components of the polaritons can be accelerated in opposite directions when the electrons are in ν = 1 integer quantum Hall state.Controlling photons with external electric or magnetic fields is an outstanding goal. On the one hand, coupling photons to artificial gauge fields holds promises for the realization of topological and strongly correlated phases of light [1][2][3][4]. On the other hand, effecting forces on photons constitutes both a problem of fundamental interest in electromagnetism and an important step in view of technological applications [5][6][7][8]. One promising avenue towards this goal is to hybridize photons with material excitations that are genuinely sensitive to gauge fields [9]. In this non-perturbative regime, exciton-polariton states are formed, ensuring that the forces acting on the material excitations are directly imprinted onto the photon. However, the neutral bosonic nature of polaritons has so far severely limited their response to gauge fields [10][11][12][13].A particularly appealing approach to circumvent this limitation is to leverage on the interaction between excitons and charges. Indeed, early reports on the drift of trions in an electric field [14,15], as well as on the Coulomb drag effect in bilayer systems [16][17][18][19] indicated that it may be possible to manipulate neutral excitations using electric fields in a solid-state setting. Recently, experimental [20] and theoretical studies [21] reported the electrical control of the speed of a polariton superfluid, raising new questions and possibilities regarding the interplay between the normal and condensed fractions of the fluid in the presence of electron-exciton interactions.While interactions between polaritons and electrons have been proposed and analyzed as a mechanism for polariton thermalization [22][23][24][25], early studies reported the modifications to polariton resonances in the presence of a Fermi sea [26][27][28]. These modifications stem form dispersive interactions between the polarizable excitonic component of the polariton with the charge-density fluctuations of the Fermi sea [29][30][31]. ...

The Free Electron Gas in Cavity Quantum Electrodynamics

“…Experimental Implications.-To a large extent this work is motivated by the great experimental progress in cavity QED materials [52,54,55,57,119] and polaritonic chemistry [37][38][39][40][41]. We believe that several of the results presented throughout the article are measurable and have experimental implications.…”

Light-induced topological superconductivity in transition metal dichalcogenide monolayers

“…Importantly, such low temperatures are within experimental reach using e.g. a He-3/He-4 dilution refrigerator [44], which gives access to temperatures down to tens of mK. We note that the ratio T c /∆ M (T = 0) ∼ 0.044 is an order of magnitude smaller than the usual BCS result 0.57.…”

Electron-exciton interactions in the exciton-polaron problem

“…The strong interlayer polaronic coupling opens new avenues to control the motion of excitons via the strong Coulomb drag effect [52], which cannot be captured by standard perturbative approaches [97]. Moreover, control over the flow of neutral excitons via electric and magnetic fields has recently been experimentally demonstrated [51].…”

“…Another outstanding question concerns the importance of the microscopic details of the X-e interactions, which have been approximated by a phenomenological contact potential in previous work [29][30][31]. These details are also essential if excitons and excess charge carriers are spatially separated into different layers, a scenario that opens new avenues to control the flow of excitons [51,52].…”