arXiv subjects

S. M. Arakelian

Publications and source records attributed to S. M. Arakelian.

At least 19 recordsLinked to original sources

arXiv2024

Non-classical effects in polariton trion

We investigate quantum phenomena in a system of three coupled microcavities. The possibility of observing polariton blockade in a dimer and triple micropillar configuration is discussed. The discovered quantum effects allow using these systems as versatile sources of individual polariton photons. Various manifestations of the quantum blockade can be tuned with the use of the pumping laser frequency. We discovered that the action of an artificial gauge field on a polariton trion causes the effect of a collective quantum blockade -- a phenomenon consisting in blocking of excitation of the state with $n$ particles distributed over multiple coupled modes. We found that when a collective quantum blockade on a non-Hermitain polariton dimer as part of the trion and a blockade on the machine itself with an antibunching effect of a micropillar coupled to the dimer, then a polariton dimer is entangled with that micropillar.

cond-mat.mes-hall↗

arXiv2021

Quantum statistics of light emitted from a pillar microcavity

A quantum behavior of the light emitted by exciton polaritons excited in a pillar semiconductor microcavity with embedded quantum well is investigated. Considering the bare excitons and photon modes as coupled quantum oscillators allows for an accurate accounting of the nonlinear and dissipative effects. In particular, using the method of quantum states presentation in a quantum phase space via quasiprobability functions (namely, a $P$-function and a Wigner function), we study the effect of the laser and the exciton-photon detuning on the second order correlation function of the emitted photons. We determine the conditions for the phenomena of bunching, giant bunching, and antibunching of the emitted light. In particular, we predict the effect of a giant bunching for the case of a large exciton to photon population ratio. Within the domain of parameters supporting a bistability regime we demonstrate the effect of bunching of photons.

cond-mat.mes-hall↗

arXiv2020

Giant synthetic gauge field for spinless microcavity polaritons in crossed electric and magnetic fields

The artificial gauge field for electrically neutral exciton polaritons devoid from the polarization degree of freedom can be synthesized by means of applying crossed electric and magnetic fields. The appearance of the gauge potential can be ascribed to the motional (magneto-electric) Stark effect which is responsible for the presence of a linear-in-momentum contribution to the exciton kinetic energy. We study the interplay of this phenomenon with the competing effect which arises from the Rabi-splitting renormalization due the reduction of the electron-hole overlap for a moving exciton. Accounting for this mechanism is crucial in the structures with the high ratio of Rabi splitting and the exciton binding energy. Besides, we propose an approach which boosts the gauge field in the considered system. It takes advantage of the crossover from the hydrogen-like exciton to the strongly dipole-polarized exciton state at a specific choice of electric and magnetic fields. The strong sensitivity of the exciton energy to the momentum in this regime leads to the large values of the gauge field. We consider the specific example of a GaAs ring-shape polariton Berry phase interferometer and show that the flux of the effective magnetic field may approach the flux quantum value in the considered crossover regime.

cond-mat.mes-hall↗

arXiv2018

Quantum metrology beyond Heisenberg limit with entangled matter wave solitons

By considering matter wave bright solitons from weakly coupled Bose-Einstein condensates trapped in a double-well potential, we study the formation of macroscopic non-classical states, including Schrödinger-cat superposition states and maximally path entangled $N00N$-states. With these macroscopic states, we examine Mach-Zehnder interferometer in the context of parity measurements, in order to obtain Heisenberg limit accuracy for linear phase shift measurement. We reveal that the ratio between two-body scattering length and intra-well hopping parameter can be measured with the scaling beyond this limit by using nonlinear phase shift with interacting quantum solitons.

quant-ph↗

arXiv2016

Light propagation in tunable exciton-polariton one-dimensional photonic crystals

Simulations of propagation of light beams in specially designed multilayer semiconductor structures (one-dimensional photonic crystals) with embedded quantum wells reveal characteristic optical properties of resonant hyperbolic metamaterials. A strong dependence of the refraction angle and the optical beam spread on the exciton radiative lifetime is revealed. We demonstrate the strong negative refraction of light and the control of the group velocity of light by an external bias through its effect upon the exciton radiative properties.

cond-mat.mes-hall↗

arXiv2015

Permanent Rabi oscillations in coupled exciton-photon systems with PT-symmetry

We propose a physical mechanism which enables permanent Rabi oscillations in driven-dissipative condensates of exciton-polaritons in semiconductor microcavities subjected to external magnetic fields. The method is based on incoherent excitonic reservoir engineering. We demonstrate that permanent non-decaying oscillations may appear due to the parity-time (PT) symmetry of the coupled exciton-photon system realised in a specific regime of pumping to the exciton state and depletion of the reservoir. For effective non-zero exciton-photon detuning, permanent Rabi oscillations occur with unequal amplitudes of exciton and photon components. Our predictions pave way to realisation of integrated circuits based on exciton-polariton condensates.

cond-mat.mes-hall↗

arXiv2015

Hyperbolic Metamaterials with Bragg Polaritons

We propose a novel mechanism for designing quantum hyperbolic metamaterials with use of semi-conductor Bragg mirrors containing periodically arrangedquantum wells. The hyperbolic dispersion of exciton-polariton modes is realized near the top of the first allowed photonic miniband in such structure which leads to formation of exciton-polariton X-waves. Exciton-light coupling provides a resonant non-linearity which leads to non-trivial topologic solutions. We predict formation of low amplitude spatially localized oscillatory structures: oscillons described by kink shaped solutions of the effective Ginzburg-Landau-Higgs equation. The oscillons have direct analogies in the gravita-tional theory. We discuss implementation of exciton-polariton Higgs fields for the Schrodinger cat state generation.

cond-mat.mes-hall↗

arXiv2013

Tunneling-assisted optical information storage with lattice polariton solitons in cavity-QED arrays

Considering two-level media in the array of weakly coupled nano-cavities, we reveal a variety of dynamical regimes, such as diffusion, self-trapping, soliton, and breathers for the wave-packets in the presence of photon tunneling processes between the next-nearest cavities. We focus our attention on the low branch (LB) bright polariton soliton formation, due to the two-body polariton-polariton scattering processes. When detuning frequency is manipulated adiabatically, the low-branch lattice polariton localized states, i.e., that are solitons and breathers evolving between photon-like and matter-like states, are shown to act as carriers for spatially distributed storage and retrieval of optical information.

cond-mat.mes-hall↗

arXiv2013

Lasing and high temperature phase transitions in atomic systems with dressed state polaritons

We consider the fundamental problem of high temperature phase transitions in the system of high density two-level atoms off-resonantly interacting with a pump field in the presence of optical collisions (OCs) and placed in the cavity. OCs are considered in the framework of thermalization of atomic dressed state (DS) population. For the case of a strong atom-field coupling condition we analyze the problem of thermodynamically equilibrium superradiant phase transition for the order parameter representing a real amplitude of cavity mode and taking place as a result of atomic DSs thermalization process. Such transition is also connected with condensed (coherent) properties of low branch (LB) DS-polaritons occurring in the cavity. For describing non-equilibrium phase transitions we derive Maxwell-Bloch like equations which account for cavity decay rate, collisional decay rate and spontaneous emission. Various aspects of transitions to laser field formation by using atomic DS levels for both positive and negative detuning of a pump field from atomic transition frequency are studied in detail. It is revealed, that for positive atom-light detuning DS lasing can be obtained in the presence of quasi-equilibrium DS population that corresponds to a true two-level atomic system with the inversion in nonresonant limit.

quant-ph↗

arXiv2013

Noise-induced topological transformations of vortex solitons in optical fibers filled with a cold atomic gas

We consider the influence of optical and temperature-dependent atomic fluctuations on the formation and propagation of optical vortex solitons in dense media realized as hollow-core optical fibers filled with a cold atomic gas in presence of optical pumping. We show different perturbation-induced scenaria of complete destruction and smooth transformations of the topological characteristics of localized optical structures in hollow-core fiber. The maximum levels of optical and atomic fluctuations at which the soliton regime can be maintained has been determined. The estimates for these levels show an opportunity to observe the optical vortex solitions in the core-filling gas of the fiber for temperatures smaller than the critical temperature for Bose-Einstein condensate.

nlin.PS↗

arXiv2012

Solitons in cavity-QED arrays containing interacting qubits

We reveal the existence of polariton soliton solutions in the array of weakly coupled optical cavities, each containing an ensemble of interacting qubits. An effective complex Ginzburg-Landau equation is derived in the continuum limit taking into account the effects of cavity field dissipation and qubit dephasing. We have shown that an enhancement of the induced nonlinearity can be achieved by two order of the magnitude with a negative interaction strength which implies a large negative qubit-field detuning as well. Bright solitons are found to be supported under perturbations only in the upper (optical) branch of polaritons, for which the corresponding group velocity is controlled by tuning the interacting strength. With the help of perturbation theory for solitons, we also demonstrate that the group velocity of these polariton solitons is suppressed by the diffusion process.

cond-mat.mes-hall↗

arXiv2012

Bose-Einstein condensation for trapped atomic polaritons in a biconical waveguide cavity

We study the problem of high temperature Bose-Einstein condensation (BEC) of atom-light polaritons in a waveguide cavity appearing due to interaction of two-level atoms with (non-resonant) quantized optical radiation, in the strong coupling regime, in the presence of optical collisions (OCs) with buffer gas particles. Specifically, we propose a special biconical waveguide cavity (BWC), permitting localization and trapping of low branch (LB) polaritons imposed by the variation of the waveguide radius in longitudinal direction. We have shown that critical temperature of BEC occurring in the system can be high enough -- few hundred Kelvins; it is connected with photon-like character of LB polaritons and strongly depends on waveguide cavity parameters. In the case of a linear trapping potential we obtain an Airy-shaped polariton condensate wave function which, when disturbed out of equilibrium, exhibits small amplitude oscillations with the characteristic period in the picosecond domain.

cond-mat.quant-gas↗

arXiv2011

Nonlinear properties and stabilities of polaritonic crystals beyond the low-excitation-density limit

Coherent properties of a two dimensional spatially periodic structure - polaritonic crystal (PolC) formed by trapped two-level atoms in an optical cavity array interacting with a light field, are analyzed. By considering the wave function overlapping both for photonic and atomic states, a cubic-quintic complex nonlinear Schrodinger equation (CNLSE) is derived for the dynamics of coupled atom-light states - wave function of low branch (LB) polaritons, associated with PolC in the continuous limit. The variational approach predicts that a stable ground state wave function of PolC exists but is accompanied by an oscillating width. For a negative scattering length, the wave function collapses in the presence of a small quintic nonlinearity appear due to a three body polariton interaction. Studying non-equilibrium (dissipative) dynamics of polaritons with adiabatic approximation we have shown that the collapse of PolC wave function can be prevented even in the presence of small decaying of a number of polariton particles.

cond-mat.mes-hall↗

arXiv2011

High temperature phase transition in the coupled atom-light system in the presence of optical collisions

The problem of photonic phase transition for the system of a two-level atomic ensemble interacting with a quantized single-mode electromagnetic field in the presence of optical collisions (OC) is considered. We have shown that for large and negative atom-field detuning a photonic field exhibits high temperature second order phase transition to superradiant state under thermalization condition for coupled atom-light states. Such a transition can be connected with superfluid (coherent) properties of photon-like low branch (LB) polaritons. We discuss the application of metallic cylindrical waveguide for observing predicted effects.

cond-mat.mes-hall↗

arXiv2010

Thermalization of coupled atom-light states in the presence of optical collisions

The interaction of a two-level atomic ensemble with a quantized single mode electromagnetic field in the presence of optical collisions (OC) is investigated both theoretically and experimentally. The main accent is made on achieving thermal equilibrium for coupled atom-light states (in particular dressed states). We propose a model of atomic dressed state thermalization that accounts for the evolution of the pseudo-spin Bloch vector components and characterize the essential role of the spontaneous emission rate in the thermalization process. Our model shows that the time of thermalization of the coupled atom-light states strictly depends on the ratio of the detuning and the resonant Rabi frequency. The predicted time of thermalization is in the nanosecond domain and about ten times shorter than the natural lifetime at full optical power in our experiment. Experimentally we are investigating the interaction of the optical field with rubidium atoms in an ultra-high pressure buffer gas cell under the condition of large atom-field detuning comparable to the thermal energy in frequency units. In particular, an observed detuning dependence of the saturated lineshape is interpreted as evidence for thermal equilibrium of coupled atom-light states. A significant modification of sideband intensity weights is predicted and obtained in this case as well.

cond-mat.mes-hall↗

arXiv2010

Strongly localized polaritons in an array of trapped two-level atoms interacting with a light field

We propose a new type of spatially periodic structure, i.e. polaritonic crystal (PolC), to observe a "slow"/"stopped" light phenomenon due to coupled atom-field states (polaritons) in a lattice. Under the tightbinding approximation, such a system realizes an array of weakly coupled trapped two-component atomic ensembles interacting with optical field in a tunnel-coupled one dimensional cavity array. We have shown that the phase transition to the superfluid Bardeen-Cooper-Schrieffer state, a so-called (BCS)-type state of low branch polaritons, occurs under the strong coupling condition. Such a transition results in the appearance of a macroscopic polarization of the atomic medium at non-zero frequency. The principal result is that the group velocity of polaritons depends essentially on the order parameter of the system, i.e. on the average photon number in the cavity array.

cond-mat.quant-gas↗

arXiv2009

Excitation of coherent polaritons in a two-dimensional atomic lattice

We describe a new type of spatially periodic structure (lattice models): a polaritonic crystal (PolC) formed by a two-dimensional lattice of trapped two-level atoms interacting with quantised electromagnetic field in a cavity (or in a one-dimensional array of tunnelling-coupled microcavities), which allows polaritons to be fully localised. Using a one-dimensional polaritonic crystal as an example, we analyse conditions for quantum degeneracy of a low-branch polariton gas and those for quantum optical information recording and storage.

quant-ph↗

arXiv2007

Josephson dynamics for coupled polariton modes under the atom-field interaction in the cavity

We consider a new approach to the problem of Bose-Einstein condensation (BEC) of polaritons for atom-field interaction under the strong coupling regime in the cavity. We investigate the dynamics of two macroscopically populated polariton modes corresponding to the upper and lower branch energy states coupled via Kerr-like nonlinearity of atomic medium. We found out the dispersion relations for new type of collective excitations in the system under consideration. Various temporal regimes like linear (nonlinear) Josephson transition and/or Rabi oscillations, macroscopic quantum self-trapping (MQST) dynamics for population imbalance of polariton modes are predicted. We also examine the switching properties for time-averaged population imbalance depending on initial conditions, effective nonlinear parameter of atomic medium and kinetic energy of low-branch polaritons.

quant-ph↗