Bosonic stimulation of cold 1s excitons into a harmonic potential minimum in Cu2_2O

Density distribution of cold exciton clouds generated into a strain-induced potential well by two-photon excitation in Cu$_2$O is studied at 2 K. We find that an anomalous spike, which can be interpreted as accumulation of the excitons into the ground state, emerges at the potential minimum. The accumulation can be due to stimulated scattering of cold excitons, mediated by acoustic phonon emission. Possibility of the formation of the thermodynamic Bose-Einstein condensate of paraexcitons has been discussed.Comment: Submitted to Solid State Communications on 17 December, 200

Higher Order Bose-Einstein Correlations test the Gaussian Density Matrix Approach

A multiparticle system produced by a large number of independent sources is described by a gaussian density matrix W. All theoretical approach to Bose-Einstein Correlatios Cn in high energy physics use this form for W. One of the most salient consequences of this form is the fact that all higher order (n>2) moments of the current distribution can be expressed in terms of the first two. We test this property by comparing the data on C2(Q^2), C3(Q^2) and C4(Q^2) from pion-p and K-p reactions at 250 GeV/c with the predictions of a general quantum statistical space-time approach. Even a simplified version of such approach can account for the data. Previous attempts along these lines, which did not use the space-time approach, met with difficulties.Comment: 17 pages (including one Table) and 2 figures. To appear in Physics Letters B (PLB 13397

Pretext, Reality, and Verisimilitude: Truth-Seeking in the Supreme Court

The assault on truth in recent public discourse makes it especially important that judicial decisions about Executive actions reflect the world as it is. Judges should not assume some idealized reality where good faith prevails, the motives of public officials are above reproach, and administrative processes are presumptively regular. Unfortunately, however, the Supreme Court has acted on naïve or counterfactual assumptions that limit judicial review of administrative or Presidential action. Such intentional judicial blindness or suspension of justified disbelief—such lack of verisimilitude—can sow doubt regarding the Court’s candor and impartiality. In analyzing the Court’s fealty to objective reality in its review of Executive actions, this Article focuses primarily on two Supreme Court decisions: the Travel Ban Case and the Census Case. These decisions illustrate how the mode of judicial review can influence verisimilitude. In the Travel Ban Case, the Court refused to look behind an implausible explanation of the government’s actions, a paradigm judicial departure from verisimilitude inimical to the legitimacy of the Court. The Census Case is a less direct assault on objective reality, as the Court ultimately did examine the truthfulness of the government’s justifications. But it did so in a manner that does not manifest a vital commitment to truth. This Article will also touch upon a third case: U.S. Department of Homeland Security v. Regents of the Univ. of Cal. (the DACA Case). The DACA Case did not challenge objective reality but on the contrary insisted that agencies provide the actual reasoning behind their decisions rather than justifications they thought of later, even if those justifications were otherwise valid. The case thus reinforces the importance of candor and accuracy. A key lesson from these cases is that to preserve its legitimacy, the Court should abandon or modify doctrines that cede judicial review of national security issues, limit consideration of `pretext, decline to assess the intent of government actors, and indulge a presumption of regularity for administrative determinations. These reforms are achievable without a major overhaul of administrative law standards

Trapping of ultracold polar molecules with a Thin Wire Electrostatic Trap

We describe the realization of a dc electric-field trap for ultracold polar molecules, the thin-wire electrostatic trap (TWIST). The thin wires that form the electrodes of the TWIST allow us to superimpose the trap onto a magneto-optical trap (MOT). In our experiment, ultracold polar NaCs molecules in their electronic ground state are created in the MOT via photoassociation, achieving a continuous accumulation in the TWIST of molecules in low-field seeking states. Initial measurements show that the TWIST trap lifetime is limited only by the background pressure in the chamber.Comment: 4 pages, 3 figure

Hadron Masses and Screening from AdS Wilson Loops

We show that in strongly coupled N=4 SYM the binding energy of a heavy and a light quark is independent of the strength of the coupling constant. As a consequence we are able to show that in the presence of light quarks the analog of the QCD string can snap and color charges are screened. The resulting neutral mesons interact with each other only via pion exchange and we estimate the massesComment: 4 pages, revte

Oscillations of solar and atmospheric neutrinos

Motivated by recent results from SuperKamiokande, we study both solar and atmospheric neutrino fluxes in the context of oscillations of the three known neutrinos. We aim at a global view which identifies the various possibilities, rather than attempting the most accurate determination of the parameters of each scenario. For solar neutrinos we emphasise the importance of performing a general analysis, independent of any particular solar model and we consider the possibility that any one of the techniques --- chlorine, gallium or water Cerenkov --- has a large unknown systematic error, so that its results should be discarded. The atmospheric neutrino anomaly is studied by paying special attention to the ratios of upward and downward going nu_e and nu_mu fluxes. Both anomalies can be described in a minimal scheme where the respective oscillation frequencies are widely separated or in non-minimal schemes with two comparable oscillation frequencies. We discuss explicit forms of neutrino mass matrices in which both atmospheric and solar neutrino fluxes are explained. In the minimal scheme we identify only two `zeroth order' textures that can result from unbroken symmetries. Finally we discuss experimental strategies for the determination of the various oscillation parameters.Comment: 20 pages, 7 figures. Final version: one reference added; fit of atmospheric neutrinos improve

Unification in models with replicated gauge groups

We examine unification of gauge couplings in four dimensional renormalizable gauge theories inspired by the latticized (deconstructed) SM or MSSM in five dimensions. The models are based on replicated gauge groups, spontaneously broken to the diagonal subgroup. The analysis is performed at one-loop level, with the contribution from the heavy vector bosons included, and compared with the analogous results in the SM or MSSM. Unification at or above the diagonal breaking scale is discussed. We find that in the considered class of extensions of the SM(MSSM) unification is possible for a wide range of unification scales and with the similar accuracy as in the SM(MSSM). Unification above the diagonal breaking scale is particularly attractive: it is a consequence of the SM(MSSM) unification, but with the unification scale depending on the number of replications of the gauge group.Comment: 19 pages, 3 figure