451 research outputs found

    Fluctuations of Rectangular Young Diagrams of Interlacing Wigner Eigenvalues

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    We prove a new CLT for the difference of linear eigenvalue statistics of a Wigner random matrix HH and its minor H^\hat H and find that the fluctuation is much smaller than the fluctuations of the individual linear statistics, as a consequence of the strong correlation between the eigenvalues of HH and H^\hat H. In particular our theorem identifies the fluctuation of Kerov's rectangular Young diagrams, defined by the interlacing eigenvalues of HH and H^\hat H, around their asymptotic shape, the Vershik-Kerov-Logan-Shepp curve. This result demonstrates yet another aspect of the close connection between random matrix theory and Young diagrams equipped with the Plancherel measure known from representation theory. For the latter a CLT has been obtained in [18] which is structurally similar to our result but the variance is different, indicating that the analogy between the two models has its limitations. Moreover, our theorem shows that Borodin's result [7] on the convergence of the spectral distribution of Wigner matrices to a Gaussian free field also holds in derivative sense.Comment: New citations and appendix added. 24 pages, 2 figures. Updated numbering to match the published versio

    Phase Transition in the Density of States of Quantum Spin Glasses

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    We prove that the empirical density of states of quantum spin glasses on arbitrary graphs converges to a normal distribution as long as the maximal degree is negligible compared with the total number of edges. This extends the recent results of [6] that were proved for graphs with bounded chromatic number and with symmetric coupling distribution. Furthermore, we generalise the result to arbitrary hypergraphs. We test the optimality of our condition on the maximal degree for pp-uniform hypergraphs that correspond to pp-spin glass Hamiltonians acting on nn distinguishable spin-1/21/2 particles. At the critical threshold p=n1/2p=n^{1/2} we find a sharp classical-quantum phase transition between the normal distribution and the Wigner semicircle law. The former is characteristic to classical systems with commuting variables, while the latter is a signature of noncommutative random matrix theory.Comment: 21 pages, 2 figure

    The Linear Boltzmann Equation as the Low Density Limit of a Random Schrodinger Equation

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    We study the evolution of a quantum particle interacting with a random potential in the low density limit (Boltzmann-Grad). The phase space density of the quantum evolution defined through the Husimi function converges weakly to a linear Boltzmann equation with collision kernel given by the full quantum scattering cross section.Comment: 74 pages, 4 figures, (Final version -- typos corrected

    Bounds on the norm of Wigner-type random matrices

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    We consider a Wigner-type ensemble, i.e. large hermitian N×NN\times N random matrices H=HH=H^* with centered independent entries and with a general matrix of variances Sxy=EHxy2S_{xy}=\mathbb E|H_{xy}|^2. The norm of HH is asymptotically given by the maximum of the support of the self-consistent density of states. We establish a bound on this maximum in terms of norms of powers of SS that substantially improves the earlier bound 2S1/22\| S\|^{1/2}_\infty given in [arXiv:1506.05098]. The key element of the proof is an effective Markov chain approximation for the contributions of the weighted Dyck paths appearing in the iterative solution of the corresponding Dyson equation.Comment: 25 pages, 8 figure

    Random Matrices with Slow Correlation Decay

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    We consider large random matrices with a general slowly decaying correlation among its entries. We prove universality of the local eigenvalue statistics and optimal local laws for the resolvent away from the spectral edges, generalizing the recent result of [arXiv:1604.08188] to allow slow correlation decay and arbitrary expectation. The main novel tool is a systematic diagrammatic control of a multivariate cumulant expansion.Comment: 41 pages, 1 figure. We corrected a typo in (4.1b

    Cusp Universality for Random Matrices I: Local Law and the Complex Hermitian Case

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    For complex Wigner-type matrices, i.e. Hermitian random matrices with independent, not necessarily identically distributed entries above the diagonal, we show that at any cusp singularity of the limiting eigenvalue distribution the local eigenvalue statistics are universal and form a Pearcey process. Since the density of states typically exhibits only square root or cubic root cusp singularities, our work complements previous results on the bulk and edge universality and it thus completes the resolution of the Wigner-Dyson-Mehta universality conjecture for the last remaining universality type in the complex Hermitian class. Our analysis holds not only for exact cusps, but approximate cusps as well, where an extended Pearcey process emerges. As a main technical ingredient we prove an optimal local law at the cusp for both symmetry classes. This result is also used in the companion paper [arXiv:1811.04055] where the cusp universality for real symmetric Wigner-type matrices is proven.Comment: 58 pages, 2 figures. Updated introduction and reference

    On a Failed Defense of Factory Farming

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    Timothy Hsiao attempts to defend industrial animal farming by arguing that it is not inherently cruel. We raise three main objections to his defense. First, his argument rests on a misunderstanding of the nature of cruelty. Second, his conclusion, though technically true, is so weak as to be of virtually no moral significance or interest. Third, his contention that animals lack moral standing, and thus that mistreating them is wrong only insofar as it makes one more disposed to mistreat other humans, is untenable on both philosophical and biological grounds
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