274 research outputs found
Stochastic Formation of Polariton Condensates in Two Degenerate Orbital States
We explore the exciton-polariton condensation in the two degenerate orbital
states. In the honeycomb lattice potential, at the third band we have two
degenerate vortex-antivortex lattice states at the inequivalent K and
K'-points. We have observed energetically degenerate condensates within the
linewidth ~ 0.3 meV, and directly measured the vortex-antivortex lattice phase
order of the order parameter. We have also observed the intensity
anticorrelation between polariton condensates at the K- and K'-points. We
relate this intensity anticorrelation to the dynamical feature of polariton
condensates induced by the stochastic relaxation from the common particle
reservoir.Comment: 5 pages, 4 figure
Quantum simulation of Fermi-Hubbard models in semiconductor quantum dot arrays
We propose a device for studying the Fermi-Hubbard model with long-range
Coulomb interactions using an array of quantum dots defined in a semiconductor
two-dimensional electron gas system. Bands with energies above the lowest
energy band are used to form the Hubbard model, which allows for an
experimentally simpler realization of the device. We find that depending on
average electron density, the system is well described by a one- or two-band
Hubbard model. Our device design enables the control of the ratio of the
Coulomb interaction to the kinetic energy of the electrons independently to the
filling of the quantum dots, such that a large portion of the Hubbard phase
diagram may be probed. Estimates of the Hubbard parameters suggest that a
metal-Mott insulator quantum phase transition and a d-wave superconducting
phase should be observable using current fabrication technologies.Comment: 12 pages, 3 figures, 1 table
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