Xuekai Ma

Creation and Manipulation of Stable Dark Solitons and Vortices in Microcavity Polariton Condensates

Solitons and vortices obtain widespread attention in different physical systems as they offer potential use in information storage, processing, and communication. In exciton-polariton condensates in semiconductor microcavities, solitons and vortices can be created optically. However, dark solitons are unstable and vortices cannot be spatially controlled. In the present work we demonstrate the existence of stable dark solitons and vortices under nonresonant incoherent excitation of a polariton condensate with a simple spatially periodic pump. In one dimension, we show that an additional coherent light pulse can be used to create or destroy a dark soliton in a controlled manner. In two dimensions we demonstrate that a coherent light beam can be used to move a vortex to a specific position on the lattice or be set into motion by simply switching the periodic pump structure from two-dimensional (lattice) to one-dimensional (stripes). Our theoretical results open up exciting possibilities for optical on-demand generation and control of dark solitons and vortices in polariton condensates.

Collective state transitions of exciton-polaritons loaded into a periodic potential

O.A.E. acknowledges financial support by the Deutsche Forschungsgemeinschaft (DFG project EG344/2-1) and by the EU project (FP7, PIRSES-GA-2013-612600) LIMACONA. I.G.S. acknowledges support from the Academy of Finland through its Centre of Excellence Programs (Projects No. 250280 and No. 251748); Government of Russian Federation (project MK-5903.2016.2); and Dynasty Foundation. E.E., T.G., I.G.S., and E.A.O. acknowledge support by the Australian Research Council.

Information processing with topologically protected vortex memories in exciton-polariton condensates

We show that in a non-equilibrium system of an exciton-polariton condensate, where polaritons are generated from incoherent pumping, a ring-shaped pump allows for stationary vortex memory elements of topological charge

Two-dimensional symbiotic solitons and vortices in binary condensates with attractive cross-species interaction

m = 1

Vortex-vortex control in exciton-polariton condensates

or

Stability of vortices and spiraling waves in non-equilibrium polariton condensates

m = -1

Instability-induced formation and nonequilibrium dynamics of phase defects in polariton condensates

. Using simple potential guides we can choose whether to copy the same charge or invert it onto another spatially separate ring pump. Such manipulation of binary information opens the possibility of a new type processing using vortices as topologically protected memory components.

Talbot effect for exciton polaritons

We consider a two-dimensional (2D) two-component spinor system with cubic attraction between the components and intra-species self-repulsion, which may be realized in atomic Bose-Einstein condensates, as well as in a quasi-equilibrium condensate of microcavity polaritons. Including a 2D spatially periodic potential, which is necessary for the stabilization of the system against the critical collapse, we use detailed numerical calculations and an analytical variational approximation (VA) to predict the existence and stability of several types of 2D symbiotic solitons in the spinor system. Stability ranges are found for symmetric and asymmetric symbiotic fundamental solitons and vortices, including hidden-vorticity (HV) modes, with opposite vorticities in the two components. The VA produces exceptionally accurate predictions for the fundamental solitons and vortices. The fundamental solitons, both symmetric and asymmetric ones, are completely stable, in either case when they exist as gap solitons or regular ones. The symmetric and asymmetric vortices are stable if the inter-component attraction is stronger than the intra-species repulsion, while the HV modes have their stability region in the opposite case.

Incoherent control of topological charges in nonequilibrium polariton condensates

Deutsche Forschungsgemeinschaft (DFG) through collaborative research center [TRR 142]; Heisenberg program

Vortex multistability and Bessel vortices in polariton condensates

We study non-equilibrium dynamics of phase dislocations and vortices in the vicinity of modulational instability of an incoherently pumped polariton condensate. In particular we discuss the mechanism of vortex destabilization and formation of spiraling waves.