1,971 research outputs found

    From the Kubo formula to variable range hopping

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    Consider a multichannel closed ring with disorder. In the semiclassical treatment its conductance is given by the Drude formula. Quantum mechanics challenge this result both in the limit of strong disorder (eigenstates are not quantum-ergodic in real space) and in the limit of weak disorder (eigenstates are not quantum-ergodic in momentum space). Consequently the analysis of conductance requires going beyond linear response theory, leading to a resistor network picture of transitions between energy levels. We demonstrate that our semi-linear response theory provides a firm unified framework from which the "hopping" phenomenology of Mott can be derived.Comment: 5 pages, published version with an extended concluding paragrap

    Neutrino neutral reaction on 4He, effects of final state interaction and realistic NN force

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    The inelastic neutral reaction of neutrino on 4He is calculated microscopically, including full final state interaction among the four nucleons. The calculation is performed using the Lorentz integral transform (LIT) method and the hyperspherical-harmonic effective interaction approach (EIHH), with a realistic nucleon-nucleon interaction. A detailed energy dependent calculation is given in the impulse approximation. With respect to previous calculations, this work predicts an increased reaction cross-section by 10%-30% for neutrino temperature up to 15 MeV.Comment: 4 pages, 2 fig

    Monte--Carlo Thermodynamic Bethe Ansatz

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    We introduce a Monte--Carlo simulation approach to thermodynamic Bethe ansatz (TBA). We exemplify the method on one particle integrable models, which include a free boson and a free fermions systems along with the scaling Lee--Yang model (SLYM). It is confirmed that the central charges and energies are correct to a very good precision, typically 0.1% or so. The advantage of the method is that it enables the calculation of all the dimensions and even the particular partition function.Comment: 22 pages. Added a footnote and realizations for the minimal models. Fortran program, mont-s.f90, available from the source lin

    Quantum pumping: The charge transported due to a translation of a scatterer

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    The amount of charge which is pushed by a moving scatterer is dQ=−GdXdQ = -G dX, where dXdX is the displacement of the scatterer. The question is what is GG. Does it depend on the transmission g0g_0 of the scatterer? Does the answer depend on whether the system is open (with leads attached to reservoirs) or closed? In the latter case: what are the implications of having ``quantum chaos" and/or coupling to to the environment? The answers to these questions illuminate some fundamental aspects of the theory of quantum pumping. For the analysis we take a network (graph) as a model system, and use the Kubo formula approach.Comment: 4 pages, 2 figures, minor changes, to be published in PRE (Rapid

    Semiclassical Description of Tunneling in Mixed Systems: The Case of the Annular Billiard

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    We study quantum-mechanical tunneling between symmetry-related pairs of regular phase space regions that are separated by a chaotic layer. We consider the annular billiard, and use scattering theory to relate the splitting of quasi-degenerate states quantized on the two regular regions to specific paths connecting them. The tunneling amplitudes involved are given a semiclassical interpretation by extending the billiard boundaries to complex space and generalizing specular reflection to complex rays. We give analytical expressions for the splittings, and show that the dominant contributions come from {\em chaos-assisted}\/ paths that tunnel into and out of the chaotic layer.Comment: 4 pages, uuencoded postscript file, replaces a corrupted versio

    Rethinking Religious Objections (Old-Testament Based) to Same-Sex Marriage

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    In Obergefell v. Hodges, the Supreme Court closed the door on one issue only to open the floodgates to another. While recognizing a constitutional right for same-sex marriage, the Court also legitimized religious objections to such unions, practically inviting complex legal challenges to its doors. In doing so, the Court also called for an open and searching debate on the issue. This Article seeks to trigger such debate. For millennia, objections to same-sex marriage were cast in religious and moral terms. The Jewish Bible ( Old Testament ), conventional wisdom argues, provided three demonstrable proofs of the Bible\u27s abhorrence of same-sex intimacy: Genesis\u27 Story of Creation, the tale of the City of Sodom (after which the dreadful term sodomy was coined), and the Levitical prohibition on same-sex intimacy. All three have reached near-axiomatic level over the years. This Article, however, offers a fresh look into these axioms, questioning their very validity. The conventional interpretation, it argues, fails to read the text in its proper context. It also fails to acknowledge the basic premise—the three organizing principles—on which the entire Jewish Bible is founded. Accordingly, a new, narrower and more congruent interpretation is offered, which properly recognizes the dignity, equality, and empathy of the original text. Religious objections to same-sex marriage are not merely academic. They have inflicted tremendous injury on members of the LGBTQ community. It is time to put those behind. The open and searching debate the Court has called for should instruct us all to move towards a more just, fair, and open society
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