Squarks in Tevatron Dilepton Events ?

We consider unusual events in the CDF and D0 dilepton+jets sample with very high ET(lepton) and ET(missing). It is possible, but very unlikely, that these events originate from top quark pair production; however, they have characteristics that are better accounted for by decays of supersymmetric quarks with mass in the region of 300 GeV.Comment: 5 pages, 2 postscript (eps) figures, uses sprocl.sty (included

B spectroscopy using all-to-all propagators

We measure the ground and excited states for B mesons in the static limit using maximally variance reduced estimators for light quark propagators. Because of the large number of propagators we are able to measure accurately also orbitally excited P, D and F states. We also present some results for Lambda_b.Comment: 3 pages, 3 figures. Talk presented at Lattice '97 by J. Peis

Finite-time quantum-to-classical transition for a Schroedinger-cat state

The transition from quantum to classical, in the case of a quantum harmonic oscillator, is typically identified with the transition from a quantum superposition of macroscopically distinguishable states, such as the Schr\"odinger cat state, into the corresponding statistical mixture. This transition is commonly characterized by the asymptotic loss of the interference term in the Wigner representation of the cat state. In this paper we show that the quantum to classical transition has different dynamical features depending on the measure for nonclassicality used. Measures based on an operatorial definition have well defined physical meaning and allow a deeper understanding of the quantum to classical transition. Our analysis shows that, for most nonclassicality measures, the Schr\"odinger cat dies after a finite time. Moreover, our results challenge the prevailing idea that more macroscopic states are more susceptible to decoherence in the sense that the transition from quantum to classical occurs faster. Since nonclassicality is prerequisite for entanglement generation our results also bridge the gap between decoherence, which appears to be only asymptotic, and entanglement, which may show a sudden death. In fact, whereas the loss of coherences still remains asymptotic, we have shown that the transition from quantum to classical can indeed occur at a finite time.Comment: 9+epsilon pages, 4 figures, published version. Originally submitted as "Sudden death of the Schroedinger cat", a bit too cool for APS policy :-

Decoherence due to three-body loss and its effect on the state of a Bose-Einstein condensate

A Born-Markov master equation is used to investigate the decoherence of the state of a macroscopically occupied mode of a cold atom trap due to three-body loss. In the large number limit only coherent states remain pure for times longer than the decoherence time: the time it takes for just three atoms to be lost from the trap. For large numbers of atoms (N>10^4) the decoherence time is found to be much faster than the phase collapse time caused by intra-trap atomic collisions

Information flow in a kinetic ising model peaks in the disordered phase

There is growing evidence that for a range of dynamical systems featuring complex interactions between large ensembles of interacting elements, mutual information peaks at order-disorder phase transitions. We conjecture that, by contrast, information flow in such systems will generally peak strictly on the disordered side of a phase transition. This conjecture is verified for a ferromagnetic 2D lattice Ising model with Glauber dynamics and a transfer entropy-based measure of systemwide information flow. Implications of the conjecture are considered, in particular, that for a complex dynamical system in the process of transitioning from disordered to ordered dynamics (a mechanism implicated, for example, in financial market crashes and the onset of some types of epileptic seizures); information dynamics may be able to predict an imminent transition

Examining \u3cem\u3eDSM\u3c/em\u3e Criteria for Trichotillomania in A Dimensional Framework: Implications for \u3cem\u3eDSM-5\u3c/em\u3e And Diagnostic Practice

Background: Diagnosis of Trichotillomania (TTM) requires meeting several criteria that aim to embody the core pathology of the disorder. These criteria are traditionally interpreted monothetically, in that they are all equally necessary for diagnosis. Alternatively, a dimensional conceptualization of psychopathology allows for examination of the relatedness of each criterion to the TTM latent continuum. Objectives: First, to examine the ability of recently removed criteria (B and C) to identify the latent dimensions of TTM psychopathology, such that they discriminate between individuals with low and high degrees of hair pulling severity. Second, to determine the impact of removing criteria B and C on the information content of remaining diagnostic criteria. Third, to determine the psychometric properties of remaining TTM diagnostic criteria that remain largely unchanged in DSM-5; that is, whether they measure distinct or overlapping levels of TTM psychopathology. Fourth, to determine whether information content derived from diagnostic criteria aid in the prediction of disease trajectory (i.e., can relapse propensity be predicted from criteria endorsement patterns). Method: Statistics derived from Item Response Theory were used to examine diagnostic criteria endorsement in 91 adults with TTM who underwent psychotherapy. Results: The removal of two criteria in DSM-5 and psychometric validity of remaining criteria was supported. Additionally, individual trait parameters were used to predict treatment progress, uncovering predictive power where none previously existed. Conclusions: Diagnostic criteria for TTM should be examined in dimensional models, which allow for nuanced and sensitive measurement of core symptomology in treatment contexts