3,125 research outputs found

    Yang-Mills equation for stable Higgs sheaves

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    We establish a Kobayashi-Hitchin correspondence for the stable Higgs sheaves on a compact Kaehler manifold. Using it, we also obtain a Kobayashi-Hitchin correspondence for the stable Higgs G-sheaves, where G is any complex reductive linear algebraic group

    On Simulating Liouvillian Flow From Quantum Mechanics Via Wigner Functions

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    The interconnection between quantum mechanics and probabilistic classical mechanics for a free relativistic particle is derived in terms of Wigner functions (WF) for both Dirac and Klein-Gordon (K-G) equations. Construction of WF is achieved by first defining a bilocal 4-current and then taking its Fourier transform w.r.t. the relative 4-coordinate. The K-G and Proca cases also lend themselves to a closely parallel treatment provided the Kemmer- Duffin beta-matrix formalism is employed for the former. Calculation of WF is carried out in a Lorentz-covariant fashion by standard `trace' techniques. The results are compared with a recent derivation due to Bosanac.Comment: 9 pages, Latex; email: [email protected]

    Optimal Cloning and Singlet Monogamy

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    The inability to produce two perfect copies of an unknown state is inherently linked with the inability to produce maximal entanglement between multiple spins. Despite this, there is no quantitative link between how much entanglement can be generated between spins (known as monogamy), and how well an unknown state can be cloned. This situation is remedied by giving a set of sufficient conditions such that the optimal Completely Positive map can be implemented as a teleportation operation into a standard, reference, state. The case of arbitrary 1 to N asymmetric cloning of d-dimensional spins can then be solved exactly, yielding the concept of `singlet monogamy'. The utility of this relation is demonstrated by calculating properties of Heisenberg systems, and contrasting them with the results from standard monogamy arguments.Comment: 4 pages, 1 figure. v2: conjecture upgraded to proof and generalized to arbitrary local hilbert space dimensions. v3: published versio

    Ultrasonic Velocity and other Parameters in Sulphuric Acid-Sodium Hydroxide Solutions

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    Ultrasonic velocity, adiabatic compressibility and refractive index have been determined in aqueous sulphuric acid=sodium hydroxide mixtures at different concentrations. Variation of these parameters with composition of the mixture was studied with a view of fix the end points of neutralization

    Decay of nuclear hyperpolarization in silicon microparticles

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    We investigate the low-field relaxation of nuclear hyperpolarization in undoped and highly doped silicon microparticles at room temperature following removal from high field. For nominally undoped particles, two relaxation time scales are identified for ambient fields above 0.2 mT. The slower, T_1s, is roughly independent of ambient field; the faster, T_1f, decreases with increasing ambient field. A model in which nuclear spin relaxation occurs at the particle surface via a two-electron mechanism is shown to be in good agreement with the experimental data, particularly the field-independence of T_1s. For boron-doped particles, a single relaxation time scale is observed. This suggests that for doped particles, mobile carriers and bulk ionized acceptor sites, rather than paramagnetic surface states, are the dominant relaxation mechanisms. Relaxation times for the undoped particles are not affected by tumbling in a liquid solution.Comment: related papers at http://marcuslab.harvard.ed

    HUNTINGTON’S DISEASE: CURRENT ADVANCES AND FUTURE PROSPECTS

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    Huntington’s disease is a neurodegenerative disease which is caused by dominantly inherited cytosine-adenine-guanine trinucleotide repeat expansion in the huntingtin gene of chromosome 4. Present survey reveals 2.7 per 100000 people are affected by huntington’s disease worldwide. The symptoms present with these patients are progressive motor, cognitive and psychiatric disorders. The early symptoms are chorea and loss of balance. This review aims to observe the present data available concerning huntington’s disease, symptoms, age of onset, risk factors, benefits of early diagnosis and genetic attribution. There is no cure for the disease. The article searched, selected and reviewed were from google scholar, medscape, NIH MedlinePlus, PubMed database using MeSH terms huntington’s disease, recent therapeutic advancement from 2003 to July 2021 with no language restriction and additional studies were included from the reference lists of relevant articles. The present review provides clinical features, diagnosis, symptomatic management and ongoing research. Hence this review will have an impact to create awareness for the society and researchers to find future treatment for Huntington’s disease

    Concurrency-aware thread scheduling for high-level synthesis

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    When mapping C programs to hardware, high-level synthesis (HLS) tools seek to reorder instructions so they can be packed into as few clock cycles as possible. However, when synthesising multi-threaded C, instruction reordering is inhibited by the presence of atomic operations (‘atomics’), such as compare- and-swap. Atomics, the fundamental concurrency primitive in C, are the basis of more abstract concurrency mechanisms such as locks, and also of efficient lock-free data structures. Whether a particular atomic can be legally reordered within a thread can depend on the memory access patterns of other threads. Existing HLS tools that support atomics typically sched- ule each thread independently, and so must be conservative when optimising around atomics. Yet HLS tools are distinguished from conventional compilers by having the entire program available. Can this information be exploited to allow more reorderings within each thread, and hence to obtain more efficient schedules? In this work, we propose a global analysis that determines, for each thread, which pairs of instructions must not be reordered. Our analysis is sensitive to the C consistency mode of the atomics involved (e.g. relaxed, release, acquire, and sequentially- consistent). We have used the Alloy model checker to validate our analysis against the C language standard, and have implemented it in the LegUp HLS tool. An evaluation on several lock-free data structure benchmarks indicates that our analysis leads to a 1.6 × average global speedup
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