Related papers: Strong interactions and bi-excitons in a polariton…
The system under consideration is a multi-component gas of interacting para- and orthoexcitons confined in a three dimensional potential trap. We calculate the spatially resolved optical emission spectrum due to interband transitions…
In spite of having finite life-time exciton-polaritons in microcavities are known to condense at strong enough pumping of the reservoir. We present an analytical theory of such Bose-condensates on a set of localized one-particle states:…
In this thesis, we study two different aspects of many-particle physics. In the first part, we study the Bose-Einstein condensation of microcavity exciton-polaritons in different artificial lattices. Bose-Einstein condensation is a quantum…
We theoretically demonstrate how the resonant coupling between a pair of cavity-polaritons and a biexciton state can lead to a large single-photon Kerr nonlinearity in a semiconductor solid-state system. A fully analytical model of the…
Complex, localized stable solitons, characterized by a power law behaviour, are found for a quasi-one-dimensional Bose-Einstein condensate near Feshbach resonance. Both dark and bright solitons can be excited in the experimentally allowed…
The many-boson problem in presence of an asymptotically narrow Feshbach resonance is considered. The low energy properties are investigated using a two-channel Hamiltonian. The energy spectrum of this model is shown to be bounded from below…
In this letter we propose a protocol to reverse a quantum many-body dynamical process. We name it "many-body echo" because the underlying physics is closely related to the spin echo effect in nuclear magnetic resonance systems. We consider…
We propose and demonstrate the appearance of an effective attractive three-body interaction in coherently-driven two-component Bose Einstein condensates. It originates from the spinor degree of freedom that is affected by a two-body…
One of the most striking quantum effects in a low temperature interacting Bose gas is superfluidity. First observed in liquid 4He, this phenomenon has been intensively studied in a variety of systems for its amazing features such as the…
We demonstrate a macro-coherent regime in exciton-polariton systems, where nonequilibrium polariton Bose--Einstein condensation coexists with macroscopically occupied vibrational states. Strong exciton-vibration coupling induces an…
Many-body eigenfunctions of the total spin operator can be constructed from the spin and spatial wavefunctions with non-trivial permutation symmetries. Spin-dependent interactions can lead to relaxation of the spin eigenstates to the…
Owing to their integer spin, exciton-polaritons in microcavities can be used for observation of non-equilibrium Bose-Einstein condensation in solid state. However, spin-related phenomena of such condensates are difficult to explore due to…
We unravel the correlation effects of the second-order quantum phase transitions emerging on the ground state of a harmonically trapped spin-1 Bose gas, upon varying the involved Zeeman terms, as well as its breathing dynamics triggered by…
We consider the condensate wavefunction of a rapidly rotating two-component Bose gas with an equal number of particles in each component. If the interactions between like and unlike species are very similar (as occurs for two hyperfine…
We report on the experimental observation of stimulated cooling in the non-equilibrium Bose-Einstein condensate (BEC) of weakly interacting exciton-polaritons from approximately room temperature down to 20K. By resolving the condensate in…
Quasiparticles and their interactions are a key part of our understanding of quantum many-body systems. Quantum simulation experiments with cold atoms have in recent years advanced our understanding of isolated quasiparticles, but so far…
We consider the Josephson Effect between two spatially separated Bose-Einstein condensates of atoms each of which can be in two hyperfine states. We derive simple equations of motion for this system closely analogous to the Bloch equations.…
The dephasing and relaxation kinetics of bosonic excitons interacting with a thermal bath of acoustic phonons is studied after coherent pulse excitation. The kinetics of the induced excitonic polarization is calculated within Markovian…
We study the collective excitation frequencies of a harmonically trapped 85Rb Bose-Einstein condensate (BEC) in the vicinity of a Feshbach resonance. To this end, we solve the underlying Gross-Pitaevskii (GP) equation by using a Gaussian…
We develop a comprehensive theoretical model for the interaction strength between a pair of exciton-polaritons in microcavity devices. Ab initio numerical calculations for dipolar polaritons in one dimension are used as a starting point to…