5,225 research outputs found
Mott-insulating and glassy phases of polaritons in 1D arrays of coupled cavities
By means of analytical and numerical methods we analyze the phase diagram of
polaritons in one-dimensional coupled cavities. We locate the phase boundary,
discuss the behavior of the polariton compressibility and visibility fringes
across the critical point, and find a non-trivial scaling of the phase boundary
as a function of the number of atoms inside each cavity. We also predict the
emergence of a polaritonic glassy phase when the number of atoms fluctuates
from cavity to cavity.Comment: 4 pages, 5 figures. Published versio
Recalibrating valence weighting biases to promote changes in rejection sensitivity and risk-taking
Past research has found that modifying individuals' valence weighting tendencies by recalibrating them to weight positive and negative valence in a more balanced manner influenced a variety of judgments. The current research examines the utility of the recalibration procedure as a targeted intervention. In Experiment 1, we recruited participants high in rejection sensitivity (who are known to exhibit a negative weighting bias) and in Experiment 2, we recruited participants with high risk tendencies (who are known to exhibit a positive weighting bias). In both experiments, participants first played BeanFest, in which they were presented with beans varying in shape and speckles and learned which increased or decreased points. They later classified the game beans, as well as novel ones varying in their resemblance to the known positives or known negatives, as good or bad. In the recalibration condition, participants were told if they classified each bean correctly, thus receiving feedback regarding the appropriate weighting of resemblance to a known positive versus a negative. The controls, who received no feedback, were less accurate at classifying the novel the beans than the recalibration participants. Furthermore, in Experiment 1, the recalibration condition subsequently exhibited lower sensitivity to rejection than the control condition, with this reduction being stronger for individuals initially higher in rejection sensitivity. This effect was still present a week later. In Experiment 2, the recalibration condition reported diminished risk-tendencies, again with this effect being stronger for individuals with initially higher riskiness, and persisting for a week. Even more importantly, recalibration participants also engaged in less risky behavior on a laboratory task
Detecting attitude change with the implicit association test
The Implicit Association Test and its variants have become pervasive measures of attitudes in a variety of domains and contexts. In two experiments, the authors provide evidence that a recent variant, the Personalized IAT developed by Olson and Fazio (2004) may more accurately detect changes in personal attitudes than the conventional Traditional IAT devised by Greenwald, McGhee, and Schwartz (1998).attitudes; attitude change; implicit attitude measures; IAT
Improving Extractions of |Vcb| and the b Quark Mass from Semileptonic Inclusive B Decay
Recent advances in improving extractions of |Vcb| and m_b from spectra of
semileptonic inclusive B decay are reported. Results of a general moment
analysis of the lepton energy spectrum and the hadronic invariant mass spectrum
are summarized. The calculation of the general O(\alpha_s) structure functions
for semileptonic B decay is reported, which has allowed the calculation of the
O(\alpha_s Lambda_{QCD} /m_b) terms for the hadronic invariant mass moments to
be carried out. Recent theoretical advances and improvements in experimental
data has allowed extractions of the CKM element |Vcb| to improve to the 2%
level.Comment: 8 pages, 2 figures. Talk given at MRST2004, May 12-14, Concordia,
Montrea
Quench dynamics of a disordered array of dissipative coupled cavities
We investigate the mean-field dynamics of a system of interacting photons in
an array of coupled cavities in presence of dissipation and disorder. We follow
the evolution of on an initially prepared Fock state, and show how the
interplay between dissipation and disorder affects the coherence properties of
the cavity emission and that these properties can be used as signatures of the
many-body phase of the whole array.Comment: 8 pages, 10 figures, new reference adde
Fully Frustrated Cold Atoms
Fully frustrated Josephson Junction arrays (FF-JJA's) exhibit a subtle
compound phase transition in which an Ising transition associated with discrete
broken translational symmetry and a Berezinskii-Kosterlitz-Thouless (BKT)
transition associated with quasi-long-range phase coherence occur nearly
simultaneously. In this Letter we discuss a cold atom realization of the FF-JJA
system. We demonstrate that both orders can be studied by standard
momentum-distribution-function measurements and present numerical results,
based on a successful self-consistent spin-wave approximation, that illustrate
the expected behavior of observables.Comment: 5 pages, 3 figures, submitte
Photoemission spectra of massless Dirac fermions on the verge of exciton condensation
Angle-resolved photoemission spectroscopy (ARPES) is a powerful probe of
electron correlations in two-dimensional layered materials. In this Letter we
demonstrate that ARPES can be used to probe the onset of exciton condensation
in spatially-separated systems of electrons and holes created by gating
techniques in either double-layer graphene or topological-insulator thin films.Comment: 5 pages, 3 figure
Role of the target orientation angle and orbital angular momentum in the evaporation residue production
The influence of the orientation angles of the target nucleus symmetry axis
relative to the beam direction on the production of the evaporation residues is
investigated for the Ca+Sm reaction as a function of the beam
energy. At low energies (137 MeV), the yield of evaporation
residues is observed only for collisions with small orientation angles
().
At large energies (about 140--180 MeV) all the orientation
angles can contribute to the evaporation residue cross section
in the 10--100 mb range, and at 180 MeV
ranges around 0.1--10 mb because the fission barrier for a compound nucleus
decreases by increasing its excitation energy and angular momentum.Comment: 20 pages, 10 figures, submitted to JPS
Exotic attractors of the non-equilibrium Rabi-Hubbard model
We explore the phase diagram of the dissipative Rabi-Hubbard model, as could
be realized by a Raman-pumping scheme applied to a coupled cavity array. There
exist various exotic attractors, including ferroelectric, antiferroelectric,
and inccomensurate fixed points, as well as regions of persistent oscillations.
Many of these features can be understood analytically by truncating to the two
lowest lying states of the Rabi model on each site. We also show that these
features survive beyond mean-field, using Matrix Product Operator simulations.Comment: 5pages, 3 figures, plus supplementary material. Final version, as
publishe
Field-induced superconductor to insulator transition in Josephson-junction ladders
The superconductor to insulator transition is studied in a self-charging
model for a ladder of Josephson-junctions in presence of an external magnetic
field. Path integral Monte Carlo simulations of the equivalent
(1+1)-dimensional classical model are used to study the phase diagram and
critical behavior. In addition to a superconducting (vortex-free) phase, a
vortex phase can also occur for increasing magnetic field and small charging
energy. It is found that an intervening insulating phase separates the
superconducting from the vortex phases. Surprisingly, a finite-size scaling
analysis shows that the field-induced superconducting to insulator transition
is in the KT universality class even tough the external field breaks
time-reversal symmetry.Comment: 5 pages, 7 figures, to appear in Phys. Rev.
- …