arXiv subjects

Anton Nalitov

Publications and source records attributed to Anton Nalitov.

6 recordsLinked to original sources

arXiv2025

Acoustic Black Holes in a Shock-Wave Exciton-Polariton Condensate

We demonstrate the spontaneous formation of acoustic black holes in exciton-polariton condensates triggered by discontinuous Riemann-type initial conditions. Starting from a quasi-conservative Gross-Pitaevskii model, we show that nonlinear dispersive shock waves naturally generate spatial regions where the local flow velocity exceeds the speed of sound, creating a self-induced transonic interface that functions as an acoustic horizon. Unlike previous schemes relying on externally engineered potentials or pump-loss landscapes, our approach reveals that the intrinsic nonlinear hydrodynamics of polariton fluids alone can lead to horizon formation. Using Whitham modulation theory and numerical simulations, we characterize the transition between subsonic and supersonic regimes and estimate the corresponding surface gravity and Hawking temperature. This mechanism opens a new route toward realizing polariton black holes and studying analogue gravitational effects, including Hawking-like emission, in Bose-Einstein quantum liquids.

cond-mat.mes-hall↗

arXiv2025

Non-Hermitian trapping of Dirac exciton-polariton condensates in a perovskite metasurface

Massless Dirac particles avoid trapping due to their exceptional tunneling properties manifested in the so-called Klein paradox. This conclusion stems from the conservative treatment, but so far, it has not been extended to a non-Hermitian framework. Recently, driven-dissipative bosonic condensation of Dirac exciton-polaritons was demonstrated in metasurface waveguides. Here, we report an experimental observation of spatial binding and energy quantization of Dirac exciton-polaritons in a halide perovskite metasurface. A combination of spatially profiled nonresonant optical excitation and exciton-polariton interaction forms an effective non-Hermitian complex potential responsible for the observed effect. In the case of tightly focused pump spots spanning from 9 to 17~$μ$m, several bound states simultaneously achieve macroscopic occupation, constituting a multi-mode bosonic condensation of exciton-polaritons. Our theoretical analysis based on the driven-dissipative extension of the Dirac equation reveals that the non-Hermitian character of the effective trap allows for confinement even in the case of the gapless Dirac-like photonic dispersion, both above and below the energy of the dispersion crossing.

cond-mat.mes-hall↗

arXiv2023

Polariton vortex Chern insulator

We propose a vortex Chern insulator, motivated by recent experimental demonstrations on programmable arrangements of cavity polariton vortices by [Alyatkin et al., ArXiv:2207.01850 (2022)] and [Wang et al., National Sci. Rev. 10, Nwac096 (2022)]. In the absence of any external fields, time-reversal symmetry is spontaneously broken through polariton condensation into structured arrangements of localized co-rotating vortices. We characterize the response of the rotating condensate lattice by calculating the spectrum of Bogoliubov elementary excitations and observe the crossing of edge-states, of opposite vorticity, connecting bands with opposite Chern numbers. The emergent topologically nontrivial energy gap stems from inherent vortex anisotropic polariton-polariton interactions and does not require any spin-orbit coupling, external magnetic fields, or elliptically polarized pump fields.

cond-mat.mes-hall↗

arXiv2018

Observation of bosonic condensation in a hybrid monolayer MoSe2-GaAs microcavity

Condensation of bosons into a macroscopic quantum state belongs to the most intriguing phenomena in nature. It was first realized in quantum gases of ultra-cold atoms, but more recently became accessible in open-dissipative, exciton-based solid-state systems at elevated temperatures. Semiconducting monolayer crystals have emerged as a new platform for studies of strongly bound excitons in ultimately thin materials. Here, we demonstrate the formation of a bosonic condensate driven by excitons hosted in an atomically thin layer of MoSe2, strongly coupled to light in a solid-state resonator. The structure is operated in the regime of collective strong coupling, giving rise to hybrid exciton-polariton modes composed of a Tamm-plasmon resonance, GaAs quantum well excitons and two-dimensional excitons confined in a monolayer of MoSe2. Polariton condensation in a monolayer crystal manifests by a superlinear increase of emission intensity from the hybrid polariton mode at injection powers as low as 4.8 pJ/pulse, as well as its density-dependent blueshift and a dramatic collapse of the emission linewidth as a hallmark of temporal coherence. Importantly, we observe a significant spin-polarization in the injected polariton condensate, a fingerprint of the core property of monolayer excitons subject to spin-valley locking. The observed effects clearly underpin the perspective of building novel highly non-linear valleytronic devices based on light-matter fluids, coherent bosonic light sources based on atomically thin materials, and paves the way towards studying materials with unconventional topological properties in the framework of bosonic condensation.

cond-mat.quant-gas↗

arXiv2017

Substrate-induced reduction of graphene thermal conductivity

We develop the theory of heat conductivity in supported graphene, accounting for coherent phonon scattering on disorder induced by an amorphous substrate. We derive spectra for in-plane and out-of-plane phonons in the framework of Green's function approach. The energetic parameters of the theory are obtained using the molecular dynamics simulations for graphene on SiO$_2$ substrate. The heat conductivity is calculated by the Boltzmann transport equation. We find that the interaction with the substrate drastically reduces the phonon lifetime and completely suppresses the contribution of ZA phonons to the heat conductivity. As a result, the total heat conductivity is reduced by several times, which matches with the tendency observed for available experimental data. The considered effect is important for managing thermal properties of the graphene-based electronic devices.

cond-mat.mes-hall↗

arXiv2015

Spin-dependent Klein tunneling in polariton graphene with photonic spin-orbit interaction

We study Klein tunneling in polariton graphene. We show that the photonic spin-orbit coupling associated with the energy splitting between TE and TM photonic modes can be described as an emergent gauge field. It suppresses the Klein tunnelling in small energy range close to the Dirac points. Thanks to polariton spin-anisotropic interactions, polarized optical pumping allows to create potential barriers acting on a single polariton spin. We show that the resulting spin-dependent Klein tunneling can be used to create a perfectly transmitting polarization rotator operating at microscopic scale.

cond-mat.mes-hall↗