463 research outputs found

    R-local Delaunay inhibition model

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    Let us consider the local specification system of Gibbs point process with inhib ition pairwise interaction acting on some Delaunay subgraph specifically not con taining the edges of Delaunay triangles with circumscribed circle of radius grea ter than some fixed positive real value RR. Even if we think that there exists at least a stationary Gibbs state associated to such system, we do not know yet how to prove it mainly due to some uncontrolled "negative" contribution in the expression of the local energy needed to insert any number of points in some large enough empty region of the space. This is solved by introducing some subgraph, called the RR-local Delaunay graph, which is a slight but tailored modification of the previous one. This kind of model does not inherit the local stability property but satisfies s ome new extension called RR-local stability. This weakened property combined with the local property provides the existence o f Gibbs state.Comment: soumis \`{a} Journal of Statistical Physics 27 page

    Bell's Jump Process in Discrete Time

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    The jump process introduced by J. S. Bell in 1986, for defining a quantum field theory without observers, presupposes that space is discrete whereas time is continuous. In this letter, our interest is to find an analogous process in discrete time. We argue that a genuine analog does not exist, but provide examples of processes in discrete time that could be used as a replacement.Comment: 7 pages LaTeX, no figure

    “A Garden of Forking Paths”: Reimagining Dreiser (Dreiser’s Path: A View With a Modern Lens. Edited by Irina V. Morozova. Moscow: RSUH Publ., 2023. 206 p.)

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    The review focuses on the collective monograph Dreiser’s Path: A View with a Modern Lens (2023). The scholarly work reevaluates Dreiser's significance as a classic of American literature and offers a contemporary perspective on his legacy through the lens of modern methodologies such as critical race theory, postcolonial theory, gender theory, etc. The attention of prominent researchers in American literature and culture from Russia, the USA, Canada, and the UK is drawn to Dreiser's contradictory and hermetic view of society and its artistic projection. The monograph reevaluates Dreiser's creative legacy, considering both major and well-known works as well as minor forms. The researchers featured in the monograph highlight the reasons why certain laws operate in Dreiser's artistic world, align Dreiser's value system with the social norms prevailing during his time, typologize the components of Dreiser's texts, and theorize them using contemporary methodological tools. They also juxtapose Dreiser's texts with other artifacts of American culture and demonstrate the evolution of Dreiser's perception from the times of the USSR to the present day. The monograph was conceived in 2021 as a special tribute to Theodore Dreiser to mark his 150 anniversary

    Phase Transition in Ferromagnetic Ising Models with Non-Uniform External Magnetic Fields

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    In this article we study the phase transition phenomenon for the Ising model under the action of a non-uniform external magnetic field. We show that the Ising model on the hypercubic lattice with a summable magnetic field has a first-order phase transition and, for any positive (resp. negative) and bounded magnetic field, the model does not present the phase transition phenomenon whenever lim infhi>0\liminf h_i> 0, where h=(hi)iZd{\bf h} = (h_i)_{i \in \Z^d} is the external magnetic field.Comment: 11 pages. Published in Journal of Statistical Physics - 201

    Universal Probability Distribution for the Wave Function of a Quantum System Entangled with Its Environment

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    A quantum system (with Hilbert space H1\mathscr{H}_1) entangled with its environment (with Hilbert space H2\mathscr{H}_2) is usually not attributed a wave function but only a reduced density matrix ρ1\rho_1. Nevertheless, there is a precise way of attributing to it a random wave function ψ1\psi_1, called its conditional wave function, whose probability distribution μ1\mu_1 depends on the entangled wave function ψH1H2\psi\in\mathscr{H}_1\otimes\mathscr{H}_2 in the Hilbert space of system and environment together. It also depends on a choice of orthonormal basis of H2\mathscr{H}_2 but in relevant cases, as we show, not very much. We prove several universality (or typicality) results about μ1\mu_1, e.g., that if the environment is sufficiently large then for every orthonormal basis of H2\mathscr{H}_2, most entangled states ψ\psi with given reduced density matrix ρ1\rho_1 are such that μ1\mu_1 is close to one of the so-called GAP (Gaussian adjusted projected) measures, GAP(ρ1)GAP(\rho_1). We also show that, for most entangled states ψ\psi from a microcanonical subspace (spanned by the eigenvectors of the Hamiltonian with energies in a narrow interval [E,E+δE][E,E+\delta E]) and most orthonormal bases of H2\mathscr{H}_2, μ1\mu_1 is close to GAP(tr2ρmc)GAP(\mathrm{tr}_2 \rho_{mc}) with ρmc\rho_{mc} the normalized projection to the microcanonical subspace. In particular, if the coupling between the system and the environment is weak, then μ1\mu_1 is close to GAP(ρβ)GAP(\rho_\beta) with ρβ\rho_\beta the canonical density matrix on H1\mathscr{H}_1 at inverse temperature β=β(E)\beta=\beta(E). This provides the mathematical justification of our claim in [J. Statist. Phys. 125:1193 (2006), http://arxiv.org/abs/quant-ph/0309021] that GAPGAP measures describe the thermal equilibrium distribution of the wave function.Comment: 27 pages LaTeX, no figures; v2 major revision with simpler proof

    Concentration inequalities for random fields via coupling

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    We present a new and simple approach to concentration inequalities for functions around their expectation with respect to non-product measures, i.e., for dependent random variables. Our method is based on coupling ideas and does not use information inequalities. When one has a uniform control on the coupling, this leads to exponential concentration inequalities. When such a uniform control is no more possible, this leads to polynomial or stretched-exponential concentration inequalities. Our abstract results apply to Gibbs random fields, in particular to the low-temperature Ising model which is a concrete example of non-uniformity of the coupling.Comment: New corrected version; 22 pages; 1 figure; New result added: stretched-exponential inequalit

    Interactive Robot for Playing Russian Checkers

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    Human\u2013robot interaction in board games is a rapidly developing field of robotics. This paper presents a robot capable of playing Russian checkers designed for entertaining, training, and research purposes. Its control program is based on a novel unsupervised self-learning algorithm inspired by AlphaZero and represents the first successful attempt of using this approach in the checkers game. The main engineering challenge in mechanics is to develop a board state acquisition system non-sensitive to lighting conditions, which is achieved by rejecting computer vision and utilizing magnetic sensors instead. An original robot face is designed to endow the robot an ability to express its attributed emotional state. Testing the robot at open-air multiday exhibitions shows the robustness of the design to difficult exploitation conditions and the high interest of visitors to the robot

    siRNAdb: a database of siRNA sequences

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    Short interfering RNAs (siRNAs) are a popular method for gene-knockdown, acting by degrading the target mRNA. Before performing experiments it is invaluable to locate and evaluate previous knockdown experiments for the gene of interest. The siRNA database provides a gene-centric view of siRNA experimental data, including siRNAs of known efficacy and siRNAs predicted to be of high efficacy by a combination of methods. Linked to these sequences is information such as siRNA thermodynamic properties and the potential for sequence-specific off-target effects. The database enables the user to evaluate an siRNA's potential for inhibition and non-specific effects. The database is available at http://siRNA.cgb.ki.se

    The meaning of the 'impact factor' in the case of an open-access journal

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    The dominant model of journal evaluation emerged at the time when there were no open-access journals, and nobody has assessed yet whether this model is able to cope with this modern reality. This commentary attempts to fill the gaps in the common understanding of the role that 'impact factor' should play in evaluation of open-access journals
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