Coherent oscillations between orbital angular momentum polariton states in an elliptic resonator

Nardin, Gaël; Léger, Yoan; Piętka, B.; Morier‐Genoud, F.; Deveaud-Plédran, Benoît

doi:10.1117/1.3609825

Cited by 4 publications

(5 citation statements)

References 27 publications

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“…We stress that, contrary to the previous demonstration of an exciton polariton vortex with a well-controlled charge [39], the shape of the optically induced ring resonator that creates a non-Hermitian potential for exciton polaritons in this work does not break the chiral symmetry. In such case, one would expect that the sign of the vortex charge would change randomly between realisations of the experiment [40,41], which is not the case here. The deterministic nature of the vortex charge has been confirmed in our experiment by blocking the pump for a sufficient time interval (up to 1 hour) to let the pump-injected reservoir disappear.…”

Section: Discussionmentioning

confidence: 77%

Chiral Modes at Exceptional Points in Exciton-Polariton Quantum Fluids

Gao

Estrecho

et al. 2018

Phys. Rev. Lett.

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We demonstrate generation of chiral modes -vortex flows with fixed handedness in excitonpolariton quantum fluids. The chiral modes arise in the vicinity of exceptional points (non-Hermitian spectral degeneracies) in an optically-induced resonator for exciton polaritons. In particular, a vortex is generated by driving two dipole modes of the non-Hermitian ring resonator into degeneracy. Transition through the exceptional point in the space of the system's parameters is enabled by precise manipulation of real and imaginary parts of the closed-wall potential forming the resonator. As the system is driven to the vicinity of the exceptional point, we observe the formation of a vortex state with a fixed orbital angular momentum (topological charge). Our method can be extended to generate high-order orbital angular momentum states through coalescence of multiple non-Hermitian spectral degeneracies, which could find application in integrated optoelectronics.Introduction. Exceptional points in wave resonators of different origin arise when both spectral positions and linewidths of two resonances coincide and the corresponding spatial modes coalesce into one [1,2]. Originally identified as an inherent property of non-Hermitian quantum systems [3][4][5], exceptional points have become a focus of intense research in classical systems with gain and loss [6], such as optical cavities [7], microwave resonators [8,15], and plasmonic nanostructures [9]. The counterintuitive behaviour of a wave system in the vicinity of an exceptional point led to demonstrations of a range of peculiar phenomena, including enhanced loss-assisted lasing [10,11], unidirectional transmission of signals [12], and loss-induced transparency [13].Due to the nontrivial topology of the exceptional point, the two eigenstates coalesce with a phase difference of ± π/2, which results in a well-defined handedness (chirality) of the surviving eigenstate [14]. This remarkable property of the eigenstate at the exceptional point was first experimentally demonstrated in a microwave cavity [15] and, very recently, led to observation of directional lasing in optical micro-resonators [16,17]. So far, the chirality of the unique eigenstate at an exceptional point has not been demonstrated in any quantum system.In this work, we demonstrate formation of a chiral state at an exceptional point in a macroscopic quantum system of condensed exciton polaritons. Exciton polaritons are hybrid light-matter bosonic quasiparticles arising due to strong coupling between excitons and photons in semiconductor microcavities [18,19]. Once sufficient density of exciton polaritons is injected by an optical or electrical pump, the transition to quantum degeneracy occurs, whereby typical signatures of a Bose-Einstein con-

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Section: Discussionmentioning

confidence: 77%

Chiral Modes at Exceptional Points in Exciton-Polariton Quantum Fluids

Gao

Estrecho

et al. 2018

Phys. Rev. Lett.

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“…This is achieved by recording the spatial interference between the polariton emission and the local oscillator, at the output of a Mach-Zehnder interferometer. 13,15,16 Polaritons are resonantly injected in a GaAs microcavity by means of a 2 ps long pulse with a given in-plane wave vector. The resulting polariton wave packet is then free to evolve in time.…”

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confidence: 99%

Dynamics of dark-soliton formation in a polariton quantum fluid

et al. 2012

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Polariton fluids have revealed huge potentialities in order to investigate the properties of bosonic fluids at the quantum scale. Among those properties, the opportunity to create dark as well as bright solitons has been demonstrated recently. In the present experiments, we image the formation dynamics of oblique dark solitons. They nucleate in the wake of an engineered attractive potential that perturbs the polariton quantum fluid. Thanks to time and phase measurements, we assess quantitatively the formation process. The formation velocity is observed to increase with increasing distance between the flow injection point and the obstacle which modulates the density distribution of the polariton fluid. We propose an explanation in terms of the increased resistance to the flow and of the conditions for the convective instability of dark solitons. By using an iterative solution of the generalized Gross-Pitaevskii equation, we are able to reproduce qualitatively our experimental results. In the recent past much effort has been devoted to characterizing the properties of quantum fluids, with particular attention given to phase transitions such as the Bose-Einstein condensate (BEC) and superfluidity. As in everyday fluids, waves and turbulence are also expected at the quantum scale. Quantized vortices 1,2 and spin texture, 3 for example, have been topics of major discussion. Presently, there is growing interest around solitons, especially in condensed matter systems. 4,5 Solitons are solitary waves which propagate in the medium while maintaining their shape. The stability of their shape is the result of the exact compensation of the dispersion by the interparticle interactions. For attractive interactions, bright solitons (BSs) are formed.5 For the opposite case of repulsion, dark solitons (DSs) may appear, having the shape of density depressions in the fluid.Originally predicted in the 1970s, 6 DSs have been experimentally observed only 20 years later in the field of nonlinear optics 7 and then in cold atom BECs by phase and density imprinting. 8,9 DSs are indeed characterized by both a density minimum and an associated phase shift. 10 However, imprinting is not the only possible way to create a DS. More recently, the growing attention to quantum hydrodynamics has triggered a clear interest towards the nucleation of DSs in the wake of an obstacle. Similar to a boat sailing across calm waters, an obstacle flowing in a quantum fluid can leave turbulence in its wake 1 and generate waves. Under particular conditions, solitons can form in the condensate.2 Such conditions are basically set out by the density and the velocity of the fluid, together with the nature of the obstacle. Recently, condensed matter systems, and in particular exciton-polaritons, have turned out to be a very accessible means to study quantum hydrodynamics. Polaritons are half-matter half-light particles arising from the strong coupling between excitons and cavity photons in a semiconductor microcavity. They have evidenced BEC 11 as well as superfluid...

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“…The tunability inherent in this non-resonant pumping mechanism provides precise control over both the size and shape of the optical trap. This allows for the selective excitation of specific superpositions involving and modes, as demonstrated in previous works 42 , 57 , 61 . Moreover, it also allows control over the corresponding energy splitting 30 .…”

Section: Model Hamiltonian and Quantum Gate Operationsmentioning

confidence: 80%

“…We assume that the system is pumped only slightly above the condensation threshold in order to avoid fragmentation of the condensate across multiple trap modes and power-induced collapse into the ground state 34 . The convenient feature of this basis is the spatial structure of the basis states which permits resonant excitation of different kinds of superpositions of and 27 , 42 , 57 , 58 . Within the two-level qubit subspace , setting , the effective single-qubit Hamiltonian can be written: …”

Section: Model Hamiltonian and Quantum Gate Operationsmentioning

confidence: 99%

“…In the context of optical traps, the equal linear combination of and states corresponds to polariton condensates with an integer orbital angular momenta (OAM), whose the p -states wavefunctions are real and characterized by odd parity. In an ideal round trap potential, these and modes are degenerate, however, any small geometric ellipticity induces an energy splitting between them 30 , 42 , 43 .…”

Section: Introductionmentioning

confidence: 99%

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Qubit gate operations in elliptically trapped polariton condensates

Ricco,

Shelykh,

Kavokin

2024

Sci Rep

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We consider bosonic condensates of exciton-polaritons optically confined in elliptical traps. A superposition of two non-degenerated p-type states of the condensate oriented along the two main axes of the trap is represented by a point on a Bloch sphere, being considered as an optically tunable qubit. We describe a set of universal single-qubit gates resulting in a controllable shift of the Bloch vector by means of an auxiliary laser beam. Moreover, we consider interaction mechanisms between two neighboring traps that enable designing two-qubit operations such as CPHASE and CNOT gates. Both the single- and two-qubit gates are analyzed in the presence of error sources in the context of polariton traps, such as pure dephasing and spontaneous relaxation mechanisms, leading to a fidelity reduction of the final qubit states and quantum concurrence, as well as the increase of Von Neumann entropy. We also discuss the applicability of our qubit proposal in the context of DiVincenzo’s criteria for the realization of local quantum computing processes. Altogether, the developed set of quantum operations would pave the way to the realization of a variety of quantum algorithms in a planar microcavity with a set of optically induced elliptical traps.

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Coherent oscillations between orbital angular momentum polariton states in an elliptic resonator

Cited by 4 publications

References 27 publications

Chiral Modes at Exceptional Points in Exciton-Polariton Quantum Fluids

Chiral Modes at Exceptional Points in Exciton-Polariton Quantum Fluids

Dynamics of dark-soliton formation in a polariton quantum fluid

Qubit gate operations in elliptically trapped polariton condensates

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