Finite-momentum condensation in a pumped microcavity

Abstract

We calculate the absorption spectra of a semiconductor microcavity into which a nonequilibrium exciton population has been pumped. We predict strong peaks in the spectrum corresponding to collective modes analogous to the Cooper modes in superconductors and fermionic atomic gases. These modes can become unstable, leading to the formation of off-equilibrium quantum condensates. We calculate a phase diagram for condensation and show that the dominant instabilities can be at a finite momentum. Thus we predict the formation of inhomogeneous condensates, similar to Fulde-Ferrel-Larkin-Ovchinnikov states.

Amplitude-Mode Dynamics of Polariton Condensates

“…where the coefficients are time dependent because the condensate oscillates with angular frequency Ω, which is the gap energy to the occupied amplitude mode. In deriving (4) we assume that the wavevectors are much smaller than the inverse of the spacing of the exciton states, so that motional narrowing is effective and the wavevector of the fluctuations is well defined [25,26].…”

Creation of entangled states in coupled quantum dots via adiabatic rapid passage

“…Within this scheme the frequency of the laser pulse is swept through that of the target state and, if whole process is performed adiabatically, this target state will be populated with high efficiency. Unlike the Rabi approach, ARP is largely unaffected by all the variations previously mentioned, and this has prompted theoretical proposals for its use in preparing populations in ensembles of QDs [8], as well as proposals to realize a non-equilibrium Bose-Einstein condensate [8][9][10] and quantum operations [11][12][13][14][15][16][17].…”

“…Unlike the Rabi approach, ARP is largely unaffected by the variations previously mentioned 7 . This has prompted a variety of theoretical proposals for applications of ARP schemes, including the preparation of exciton populations in ensembles of quantum dots 8 , and the implementation of quantum operations [9][10][11][12][13][14][15][16] and forms of Bose-Einstein condensation 8,17,18 .…”