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 $^{48}$Ca+$^{154}$Sm reaction as a function of the beam energy. At low energies ($E_{\rm c.m.}<$137 MeV), the yield of evaporation residues is observed only for collisions with small orientation angles ($\alpha_T<45^0$). At large energies (about $E_{\rm c.m.}=$140--180 MeV) all the orientation angles $\alpha_T$ can contribute to the evaporation residue cross section $\sigma_{ER}$ in the 10--100 mb range, and at $E_{c.m.}>$180 MeV $\sigma_{ER}$ 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.