18,201 research outputs found

    First eigenvalue of the pp-Laplace operator along the Ricci flow

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    In this paper, we mainly investigate continuity, monotonicity and differentiability for the first eigenvalue of the pp-Laplace operator along the Ricci flow on closed manifolds. We show that the first pp-eigenvalue is strictly increasing and differentiable almost everywhere along the Ricci flow under some curvature assumptions. In particular, for an orientable closed surface, we construct various monotonic quantities and prove that the first pp-eigenvalue is differentiable almost everywhere along the Ricci flow without any curvature assumption, and therefore derive a pp-eigenvalue comparison-type theorem when its Euler characteristic is negative.Comment: 28 pages, added statements and references, deleted verbose statements and corrected typo

    Geometric Steering Criterion for Two-qubit States

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    According to the geometric characterization of measurement assemblages and local hidden state (LHS) models, we propose a steering criterion which is both necessary and sufficient for two-qubit states under arbitrary measurement sets. A quantity is introduced to describe the required local resources to reconstruct a measurement assemblage for two-qubit states. We show that the quantity can be regarded as a quantification of steerability and be used to find out optimal LHS models. Finally we propose a method to generate unsteerable states, and construct some two-qubit states which are entangled but unsteerable under all projective measurements

    Characterizing Nonlocal Correlations via Universal Uncertainty Relations

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    Characterization and certification of nonlocal correlations is one of the the central topics in quantum information theory. In this work, we develop the detection methods of entanglement and steering based on the universal uncertainty relations and fine-grained uncertainty relations. In the course of our study, the uncertainty relations are formulated in majorization form, and the uncertainty quantifier can be chosen as any convex Schur concave functions, this leads to a large set of inequalities, including all existing criteria based on entropies. We address the question that if all steerable states (or entangled states) can be witnessed by some uncertainty-based inequality, we find that for pure states and many important families of states, this is the case

    Some Spectral Properties and Characterizations of Connected Odd-bipartite Uniform Hypergraphs

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    A kk-uniform hypergraph G=(V,E)G=(V,E) is called odd-bipartite ([5]), if kk is even and there exists some proper subset V1V_1 of VV such that each edge of GG contains odd number of vertices in V1V_1. Odd-bipartite hypergraphs are generalizations of the ordinary bipartite graphs. We study the spectral properties of the connected odd-bipartite hypergraphs. We prove that the Laplacian H-spectrum and signless Laplacian H-spectrum of a connected kk-uniform hypergraph GG are equal if and only if kk is even and GG is odd-bipartite. We further give several spectral characterizations of the connected odd-bipartite hypergraphs. We also give a characterization for a connected kk-uniform hypergraph whose Laplacian spectral radius and signless Laplacian spectral radius are equal, thus provide an answer to a question raised in [9]. By showing that the Cartesian product Gβ–‘HG\Box H of two odd-bipartite kk-uniform hypergraphs is still odd-bipartite, we determine that the Laplacian spectral radius of Gβ–‘HG\Box H is the sum of the Laplacian spectral radii of GG and HH, when GG and HH are both connected odd-bipartite.Comment: 16 page

    Monogamy Relation in No-disturbance Theories

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    The monogamy is a fundamental property of Bell nonlocality and contextuality. In this article, we studied the nn-cycle noncontextual inequalities and generalized CHSH inequalities in detail and found the sufficient conditions for those inequalities to be hold. According to those conditions, we provide several kind of tradeoff relations: monogamy of generalized Bell inequalities in non-signaling framework, monogamy of cycle type noncontextual inequalities and monogamy between Bell inequality and noncontextual inequality in general no-disturbance framework. At last, some generic tradeoff relations of generalized CHSH inequalities for nn-party physical systems, which are beyond one-to-many scenario, are discussed

    Geometric Local Hidden State Model for Some Two-qubit States

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    Adopting the geometric description of steering assemblages and local hidden states (LHS) model, we construct the optimal LHS model for some two-qubit states under continuous projective measurements, and obtain a sufficient steering criterion for all two-qubit states. Using the criterion, we show more two-qubit states that are asymmetric in steering scenario under projective measurements. Then we generalize the geometric description into higher dimensional bipartite cases, calculate the steering bound of two-qutrit isotropic states and make discussion on more general cases

    Hierarchy of Genuine Multipartite Quantum Correlations

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    Classifying states which exhibiting different statistical correlations is among the most important problems in quantum information science and quantum many-body physics. In bipartite case, there is a clear hierarchy of states with different correlations: total correlation (T) βŠ‹\supsetneq discord (D) βŠ‹\supsetneq entanglement (E) βŠ‹\supsetneq steering (S) βŠ‹\supsetneq Bell~nonlocality (NL). However, very little is known about genuine multipartite correlations (GMC\mathcal{C}) for both conceptual and technical difficulties. In this work, we show that, for any NN-partite qudit states, there also exist such a hierarchy: genuine multipartite total correlations (GMT) βŠ‡\supseteq genuine multipartite discord (GMD) βŠ‡\supseteq genuine multipartite entanglement (GME) βŠ‡\supseteq genuine multipartite steering (GMS) βŠ‡\supseteq genuine multipartite nonlocality (GMNL). Furthermore, by constructing precise states, we show that GMT, GME and GMS are inequivalent with each other, thus GMT βŠ‹\supsetneq GME βŠ‹\supsetneq GMS

    Entropic No-Disturbance as a Physical Principle

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    The celebrated Bell-Kochen-Specker no-go theorem asserts that quantum mechanics does not present the property of realism, the essence of the theorem is the lack of a joint probability distributions for some experiment settings. In this work, we exploit the information theoretic form of the theorem using information measure instead of probabilistic measure and indicate that quantum mechanics does not present such entropic realism neither. The entropic form of Gleason's no-disturbance principle is developed and it turns out to be characterized by the intersection of several entropic cones. Entropic contextuality and entropic nonlocality are investigated in depth in this framework. We show how one can construct monogamy relations using entropic cone and basic Shannon-type inequalities. The general criterion for several entropic tests to be monogamous is also developed, using the criterion, we demonstrate that entropic nonlocal correlations are monogamous, entropic contextuality tests are monogamous and entropic nonlocality and entropic contextuality are also monogamous. Finally, we analyze the entropic monogamy relations for multiparty and many-test case, which plays a crucial role in quantum network communication

    Assertion-Based Design Exploration of DVS in Network Processor Architectures

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    With the scaling of technology and higher requirements on performance and functionality, power dissipation is becoming one of the major design considerations in the development of network processors. In this paper, we use an assertion-based methodology for system-level power/performance analysis to study two dynamic voltage scaling (DVS) techniques, traffic-based DVS and execution-based DVS, in a network processor model. Using the automatically generated distribution analyzers, we analyze the power and performance distributions and study their trade-offs for the two DVS policies with different parameter settings such as threshold values and window sizes. We discuss the optimal configurations of the two DVS policies under different design requirements. By a set of experiments, we show that the assertion-based trace analysis methodology is an efficient tool that can help a designer easily compare and study optimal architectural configurations in a large design space.Comment: Submitted on behalf of EDAA (http://www.edaa.com/

    An Efficient Algorithmic Way to Construct Boltzmann Machine Representations for Arbitrary Stabilizer Code

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    An efficient algorithm for constructing restricted Boltzmann machine (RBM) architecture of arbitrary stabilizer group is presented. Some partial results of this problem have been given in arXiv:1802.03738, in this work we give a complete solution via a different approach. We show that by transforming a stabilizer group into the standard form, every stabilizer code state can be efficiently represented by RBM architecture and we can explicitly get the RBM parameters in this algorithmic way
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