19 research outputs found
Majorana-Like Modes of Light in a One-Dimensional Array of Nonlinear Cavities
The search for Majorana fermions in p-wave paired fermionic systems has
recently moved to the forefront of condensed-matter research. Here we propose
an alternative route and show theoretically that Majorana-like modes can be
realized and probed in a driven-dissipative system of strongly correlated
photons consisting of a chain of tunnel-coupled cavities, where p-wave pairing
effectively arises from the interplay between strong on-site interactions and
two-photon parametric driving. The nonlocal nature of these exotic modes could
be demonstrated through cross-correlation measurements carried out at the ends
of the chain---revealing a strong photon bunching signature---and their
non-Abelian properties could be simulated through tunnel-braid operations.Comment: 5 pages, 2 figures; with Supplemental Material (12 pages
Self-construals and values in different cultural and socioeconomic contexts
In this study the authors investigated (a) how individuational and relational self-orientations, as well as self-directed and other-directed values, are related to one another, and (b) how these self- and value orientations differ across 2 cultural (i.e., 422 Turkish and 441 American university students) and 2 socioeconomic status (SES) groups (i.e., 186 lower SES and 167 upper SES Turkish high school students). Across cross-cultural and SES groups, individuational and relational self-orientations appeared to be not opposite but distinct orientations, as predicted by the Balanced Integration-Differentiation (BID) model (E. O. Imamoǧlu, 2003). Furthermore, both Turkish and American students with similar self-construal types, as suggested by the BID model, showed similar value orientations, pointing to both cross-cultural similarities and within-cultural diversity. Individuational and relational self-orientations showed weak to moderate associations with the respective value domains of self-directedness and other-directedness, which seemed to represent separate but somewhat positively correlated orientations. In both cross-cultural and SES groups, students tended to be high in both relational and individ-uational self-orientations; those trends were particularly strong among the Turkish and American women compared with men and among the upper SES Turkish adolescents compared with lower SES adolescents. Results are discussed as contesting the assumptions that regard the individuational and relational orientations as opposites and as supporting the search for invariant aspects of psychological functioning across contexts
Fermionized photons in an array of driven dissipative nonlinear cavities
We theoretically investigate the optical response of a one-dimensional array
of strongly nonlinear optical microcavities. When the optical nonlinearity is
much larger than both losses and inter-cavity tunnel coupling, the
non-equilibrium steady state of the system is reminiscent of a strongly
correlated Tonks-Girardeau gas of impenetrable bosons. Signatures of strong
correlations are identified in the absorption spectrum of the system, as well
as in the intensity correlations of the emitted light. Possible experimental
implementations in state-of-the-art solid-state devices are discussed
Coulomb-enhanced dynamic localization and Bell state generation in coupled quantum dots
We investigate the dynamics of two interacting electrons in coupled quantum
dots driven by an AC field. We find that the two electrons can be trapped in
one of the dots by the AC field, in spite of the strong Coulomb repulsion. In
particular, we find that the interaction may enhance the localization effect.
We also demonstrate the field excitation procedure to generate the maximally
entangled Bell states. The generation time is determined by both analytic and
numerical solutions of the time dependent Schrodinger equation.Comment: 12 pages, 5 figure
Strong extinction of a far-field laser beam by a single quantum dot
Through the utilization of index-matched GaAs immersion lens techniques we
demonstrate a record extinction (12%) of a far-field focused laser by a single
InAs/GaAs quantum dot. This contrast level enables us to report for the first
time resonant laser transmission spectroscopy on a single InAs/GaAs quantum dot
without the need for phase-sensitive lock-in detection
Size-dependent decoherence of excitonic states in semiconductor microcrystallites
The size-dependent decoherence of the exciton states resulting from the
spontaneous emission is investigated in a semiconductor spherical
microcrystallite under condition . In general, the
larger size of the microcrystallite corresponds to the shorter coherence time.
If the initial state is a superposition of two different excitonic coherent
states, the coherence time depends on both the overlap of two excitonic
coherent states and the size of the microcrystallite. When the system with
fixed size is initially in the even or odd coherent states, the larger average
number of the excitons corresponds to the faster decoherence. When the average
number of the excitons is given, the bigger size of the microcrystallite
corresponds to the faster decoherence. The decoherence of the exciton states
for the materials GaAs and CdS is numerically studied by our theoretical
analysis.Comment: 4 pages, two figure
Quantum trajectory approach to stochastically-induced quantum interference effects in coherently-driven two-level atoms
Stochastic perturbation of two-level atoms strongly driven by a coherent
light field is analyzed by the quantum trajectory method. A new method is
developed for calculating the resonance fluorescence spectra from numerical
simulations. It is shown that in the case of dominant incoherent perturbation,
the stochastic noise can unexpectedly create phase correlation between the
neighboring atomic dressed states. This phase correlation is responsible for
quantum interference between the related transitions resulting in anomalous
modifications of the resonance fluorescence spectra.Comment: paper accepted for publicatio
Monte Carlo model for the photoluminescence kinetics of a quantum dot embedded in a nanocavity
We address the problem of the photoluminescence of a quantum (QD) dot in a nanocavity, with focus on the case of nonzero detuning. In this regime, experiments have shown that strong emission from the cavity-like peak is still present for dot-cavity detuning exceeding 10 meV, which seems puzzling. We will discuss the general theory of cavity feeding, due to the relaxation and recombination kinetics of a multiply excited QD. We first compute the multi-exciton manifolds using a configuration-interaction scheme, starting from a truncated single-particle basis. We then run Monte-Carlo paths of excitation-emission kinetics on these states. This allows to extract photoluminescence spectra and two-photon correlation curves. The agreement with experimental data[1, 2] is very good. Our result shows unambiguously that the cavity feeding mechanism at large detunings can be attributed to excited-state multiexciton radiative decay (mostly biexcitons), also involving states in the wetting layer continuum.4 page(s