• Dynamics of spin polarization in tilted polariton rings

      Mukherjee, S; Kozin, VK; Nalitov, AV; Shelykh, IA; Sun, Z; Myers, DM; Ozden, B; Beaumariage, J; Steger, M; Pfeiffer, LN; et al. (American Physical Society, 2021-04-22)
      We have observed the effect of pseudomagnetic field originating from the polaritonic analog of spin-orbit coupling [transverse electric and transverse magnetic (TE-TM) splitting] on a polariton condensate in a ring-shaped microcavity. The effect gives rise to a stable four-leaf pattern around the ring as seen from the linear polarization measurements of the condensate photoluminescence. This pattern is found to originate from the interplay of the cavity potential, energy relaxation, and TE-TM splitting in the ring. Our observations are compared to the dissipative one-dimensional spinor Gross-Pitaevskii equation with the TE-TM splitting energy, which shows good qualitative agreement.
    • Formation of nonlinear X-waves in condensed matter systems

      Colas, David; Laussy, Fabrice P; Davis, Matthew J (American Physical Society (APS), 2019-06-10)
      X-waves are an example of a localized wave packet solution of the homogeneous wave equation, and can potentially arise in any area of physics relating to wave phenomena, such as acoustics, electromagnetism, or quantum mechanics. They have been predicted in condensed matter systems such as atomic Bose-Einstein condensates in optical lattices, and were recently observed in exciton-polariton condensates. Here we show that polariton X-waves result from an interference between two separating wave packets that arise from the combination of a locally hyperbolic dispersion relation and nonlinear interactions. We show that similar X-wave structures could also be observed in expanding spin-orbit coupled Bose-Einstein condensates.
    • Kinetic Monte Carlo approach to nonequilibrium bosonic systems

      Liew, T. C. H.; Flayac, H.; Poletti, D.; Savenko, I. G.; Laussy, Fabrice (American Physical Society, 2017-09-18)
      We consider the use of a kinetic Monte Carlo approach for the description of nonequilibrium bosonic systems, taking nonresonantly excited exciton-polariton condensates and bosonic cascade lasers as examples. In the former case, the considered approach allows the study of the cross-over between incoherent and coherent regimes, which represents the formation of a quasicondensate that forms purely from the action of energy relaxation processes rather than interactions between the condensing particles themselves. In the latter case, we show theoretically that a bosonic cascade can develop an output coherent state.
    • Optically controlled polariton condensate molecules

      Cherotchenko, ED; Sigurdsson, H; Askitopoulos, A; Nalitov, AV (American Physical Society, 2021-03-29)
      A condensed-matter platform for analog simulation of complex two-dimensional molecular bonding configurations, based on optically trapped exciton-polariton condensates is proposed. The stable occupation of polariton condensates in the excited states of their optically configurable potential traps permits emulation of excited atomic orbitals. A classical mean-field model describing the dissipative coupling mechanism between p-orbital condensates is derived, identifying lowest-threshold condensation solutions as a function of trap parameters corresponding to bound and antibound π and σ bonding configurations, similar to those in quantum chemistry.
    • Quantum metric and wave packets at exceptional points in non-Hermitian systems

      Solnyshkov, DD; Leblanc, C; Bessonart, L; Nalitov, A; Ren, J; Liao, Q; Li, F; Malpuech, G (American Physical Society, 2021-03-11)
      The usual concepts of topological physics, such as the Berry curvature, are not always relevant for non-Hermitian systems. We show that another object, the quantum metric, which often plays a secondary role in Hermitian systems, becomes a crucial quantity near exceptional points in non-Hermitian systems, where it diverges in a way that fully controls the description of wave-packet trajectories. The quantum metric behavior is responsible for a constant acceleration with a fixed direction, and for a nonvanishing constant velocity with a controllable direction. Both contributions are independent of the wave-packet size.
    • Spinning polariton vortices with magnetic field

      Yulin, AV; Nalitov, AV; Shelykh, IA (American Physical Society, 2020-03-12)
      We study the formation dynamics of spinor polariton condensates trapped in ring-shaped confining potentials created by excitonic reservoirs. We consider in detail the interplay of the effective spin-orbit interaction provided by transverse electric and transverse magnetic photonic modes splitting (TE-TM splitting) and exciton Zeeman splitting provided by an external magnetic field. We demonstrate that tuning of the trap size obtained by shaping of the external nonresonant and depolarized pumping allows formation of pairs of half-vortices of topological charges ±1/2 in both spin components. Further, we show that the probabilities of the realizations of four possible vortex configurations strongly depend on the value of the magnetic field. For certain values of the field, the probability of the formation of a vortex with desired topological charge reaches 90%, which opens the possibility of on-demand control of angular momentum of quantum fluids of light with a magnetic field.
    • Spontaneous topological transitions in a honeycomb lattice of exciton-polariton condensates due to spin bifurcations

      Sigurdsson, H; Krivosenko, YS; Iorsh, IV; Shelykh, IA; Nalitov, AV (American Physical Society, 2019-12-23)
      We theoretically study the spontaneous formation of the quantum anomalous Hall effect in a graphene system of spin-bifurcated exciton-polariton condensates under nonresonant pumping. We demonstrate that, depending on the parameters of the structure, such as intensity of the pump and coupling strength between condensates, the system shows a rich variety of macroscopic magnetic ordering, including analogs of ferromagnetic, antiferromagnetic, and resonant valence bond phases. Transitions between these magnetic polarized phases are associated with dramatic reshaping of the spectrum of the system connected with spontaneous appearance of topological order.