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  • Publication . Article . Preprint . 1995
    Open Access English
    Authors: 
    Peres, Asher;

    Experimental tests of Bell inequalities ought to take into account all detection events. If the latter are postselected, and only some of these events are included in the statistical analysis, a Bell inequality may be violated, even by purely classical correlations. The paradoxical properties of Werner states, recently pointed out by Popescu, can be explained as the result of a postselection of the detection events, or, equivalently, as due to the preparation of a new state by means of a nonlocal process. 7 pages LaTeX

  • Publication . Preprint . Article . 2012
    Open Access
    Authors: 
    P. L. Krapivsky; Baruch Meerson; Pavel V. Sasorov;
    Publisher: IOP Publishing

    What is the probability that a macroscopic void will spontaneously arise, at a specified time T, in an initially homogeneous gas? We address this question for diffusive lattice gases, and also determine the most probable density history leading to the void formation. We employ the macroscopic fluctuation theory by Bertini et al and consider both annealed and quenched averaging procedures (the initial condition is allowed to fluctuate in the annealed setting). We show that in the annealed case the void formation probability is given by the equilibrium Boltzmann-Gibbs formula, so the probability is independent of T (and also of the void shape, as only the volume matters). In the quenched case, which is intrinsically non-equilibrium, we evaluate the void formation probability analytically for non-interacting random walkers and probe it numerically for the simple symmetric exclusion process. For voids that are small compared with the diffusion length, the equilibrium result for the void formation probability is recovered. We also re-derive our main results for non-interacting random walkers from an exact microscopic analysis. Comment: 23 pages, 7 figures

  • Open Access
    Authors: 
    Zucker, David M.; Gorfine, Malka; Hsu, Li;
    Publisher: arXiv

    In this work we present a simple estimation procedure for a general frailty model for analysis of prospective correlated failure times. Earlier work showed this method to perform well in a simulation study. Here we provide rigorous large-sample theory for the proposed estimators of both the regression coefficient vector and the dependence parameter, including consistent variance estimators.

  • Open Access
    Authors: 
    Aaron A. Dutton; Andrea V. Macciò; Jonas Frings; Liang Wang; G. S. Stinson; Camilla Penzo; Xi Kang;
    Publisher: Oxford University Press (OUP)
    Project: EC | MW-DISK (321035)

    We compare the half-light circular velocities, V_{1/2}, of dwarf galaxies in the Local Group to the predicted circular velocity curves of galaxies in the NIHAO suite of LCDM simulations. We use a subset of 34 simulations in which the central galaxy has a stellar luminosity in the range 0.5 x 10^5 < L_V < 2 x 10^8 L_{sun}. The NIHAO galaxy simulations reproduce the relation between stellar mass and halo mass from abundance matching, as well as the observed half-light size vs luminosity relation. The corresponding dissipationless simulations over-predict the V_{1/2}, recovering the problem known as too big to fail (TBTF). By contrast, the NIHAO simulations have expanded dark matter haloes, and provide an excellent match to the distribution of V_{1/2} for galaxies with L_V > 2 x 10^6 L_{sun}. For lower luminosities our simulations predict very little halo response, and tend to over predict the observed circular velocities. In the context of LCDM, this could signal the increased stochasticity of star formation in haloes below M_{halo} \sim 10^{10} M_{sun}, or the role of environmental effects. Thus, haloes that are "too big to fail", do not fail LCDM, but haloes that are "too small to pass" (the galaxy formation threshold) provide a future test of LCDM. 6 pages, 3 figures, accepted to MNRAS letters

  • Publication . Preprint . Article . 2017
    Open Access English
    Authors: 
    Shalev-Shwartz, Shai; Shamir, Ohad; Shammah, Shaked;

    In recent years, Deep Learning has become the go-to solution for a broad range of applications, often outperforming state-of-the-art. However, it is important, for both theoreticians and practitioners, to gain a deeper understanding of the difficulties and limitations associated with common approaches and algorithms. We describe four types of simple problems, for which the gradient-based algorithms commonly used in deep learning either fail or suffer from significant difficulties. We illustrate the failures through practical experiments, and provide theoretical insights explaining their source, and how they might be remedied.

  • Publication . Article . Preprint . 2017 . Embargo End Date: 01 Jan 2017
    Open Access
    Authors: 
    Rapaport, Ariel;
    Publisher: arXiv
    Project: EC | FRACTALSANDMETRICNT (306494)

    We show there exists a constant $0

  • Publication . Article . Preprint . 2017
    Open Access English
    Authors: 
    Vladimir Gol'dshtein; Valerii Pchelintsev; Alexander Ukhlov;
    Country: Russian Federation

    In this paper we apply estimates of the norms of Sobolev extension operators to the spectral estimates of of the first nontrivial Neumann eigenvalue of the Laplace operator in non-convex extension domains. As a consequence we obtain a connection between resonant frequencies of free membranes and the smallest-circle problem (initially proposed by J.~J.~Sylvester in 1857). 12 pages

  • Publication . Article . Preprint . 1996
    Open Access
    Authors: 
    Paul Biran;
    Publisher: Springer Science and Business Media LLC

    We discuss closed symplectic 4-manifolds which admit full symplectic packings by $N$ equal balls for large $N$'s. We give a homological criterion for recognizing such manifolds. As a corollary we prove that ${\Bbb C}P^2$ can be fully packed by $N$ equal balls for every $N\geq 9$. Comment: 12 pages, written in Amslatex. (A few mathematical typos fixed)

  • Publication . Conference object . Preprint . Article . Contribution for newspaper or weekly magazine . 2017 . Embargo End Date: 01 Jan 2016
    Open Access
    Authors: 
    Kashyap Thimmaraju; Liron Schiff; Stefan Schmid;
    Publisher: arXiv
    Country: Denmark

    Software-defined networking is considered a promising new paradigm, enabling more reliable and formally verifiable communication networks. However, this paper shows that the separation of the control plane from the data plane, which lies at the heart of Software-Defined Networks (SDNs), introduces a new vulnerability which we call \emph{teleportation}. An attacker (e.g., a malicious switch in the data plane or a host connected to the network) can use teleportation to transmit information via the control plane and bypass critical network functions in the data plane (e.g., a firewall), and to violate security policies as well as logical and even physical separations. This paper characterizes the design space for teleportation attacks theoretically, and then identifies four different teleportation techniques. We demonstrate and discuss how these techniques can be exploited for different attacks (e.g., exfiltrating confidential data at high rates), and also initiate the discussion of possible countermeasures. Generally, and given today's trend toward more intent-based networking, we believe that our findings are relevant beyond the use cases considered in this paper. Comment: Accepted in EuroSP'17

  • Publication . Preprint . Article . 2012 . Embargo End Date: 01 Jan 2012
    Open Access
    Authors: 
    Inoue, Hiroyuki;
    Publisher: arXiv

    The progress in nanofabrication, measurement technology, and mesoscopic transport theory has been expanding the field of shot noise. Although a wave-packet approach to DC shot noise of independent electrons at finite temperature was offered as an intuitive alternative to the sophisticated theories, actual shot noise data often behave more complicated than the derived simple expression. For example, so-called effective charge can deviate from elementary electronic charge due to correlated tunnelings. Also, there are cases where one wishes to know the full spectrum of the shot noise. It will be of great use if a handy method for the shot noise in various experimental situations is available. In this article, a classical wave-packet approach to the shot noise is presented. The classical formulation provides a rigorous yet straightforward formalism to compute the full spectrum and, furthermore, clarifies the structure of Fano factor and effective charge. Additionally, the role of realistic detectors and an application to cross correlation measurements are also discussed. The present method can serve as an intuitive complement to the full quantum mechanical and field theoretical approaches.

Advanced search in
Research products
arrow_drop_down
Searching FieldsTerms
Any field
arrow_drop_down
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arrow_drop_down
Include:
33,740 Research products, page 1 of 3,374
  • Publication . Article . Preprint . 1995
    Open Access English
    Authors: 
    Peres, Asher;

    Experimental tests of Bell inequalities ought to take into account all detection events. If the latter are postselected, and only some of these events are included in the statistical analysis, a Bell inequality may be violated, even by purely classical correlations. The paradoxical properties of Werner states, recently pointed out by Popescu, can be explained as the result of a postselection of the detection events, or, equivalently, as due to the preparation of a new state by means of a nonlocal process. 7 pages LaTeX

  • Publication . Preprint . Article . 2012
    Open Access
    Authors: 
    P. L. Krapivsky; Baruch Meerson; Pavel V. Sasorov;
    Publisher: IOP Publishing

    What is the probability that a macroscopic void will spontaneously arise, at a specified time T, in an initially homogeneous gas? We address this question for diffusive lattice gases, and also determine the most probable density history leading to the void formation. We employ the macroscopic fluctuation theory by Bertini et al and consider both annealed and quenched averaging procedures (the initial condition is allowed to fluctuate in the annealed setting). We show that in the annealed case the void formation probability is given by the equilibrium Boltzmann-Gibbs formula, so the probability is independent of T (and also of the void shape, as only the volume matters). In the quenched case, which is intrinsically non-equilibrium, we evaluate the void formation probability analytically for non-interacting random walkers and probe it numerically for the simple symmetric exclusion process. For voids that are small compared with the diffusion length, the equilibrium result for the void formation probability is recovered. We also re-derive our main results for non-interacting random walkers from an exact microscopic analysis. Comment: 23 pages, 7 figures

  • Open Access
    Authors: 
    Zucker, David M.; Gorfine, Malka; Hsu, Li;
    Publisher: arXiv

    In this work we present a simple estimation procedure for a general frailty model for analysis of prospective correlated failure times. Earlier work showed this method to perform well in a simulation study. Here we provide rigorous large-sample theory for the proposed estimators of both the regression coefficient vector and the dependence parameter, including consistent variance estimators.

  • Open Access
    Authors: 
    Aaron A. Dutton; Andrea V. Macciò; Jonas Frings; Liang Wang; G. S. Stinson; Camilla Penzo; Xi Kang;
    Publisher: Oxford University Press (OUP)
    Project: EC | MW-DISK (321035)

    We compare the half-light circular velocities, V_{1/2}, of dwarf galaxies in the Local Group to the predicted circular velocity curves of galaxies in the NIHAO suite of LCDM simulations. We use a subset of 34 simulations in which the central galaxy has a stellar luminosity in the range 0.5 x 10^5 < L_V < 2 x 10^8 L_{sun}. The NIHAO galaxy simulations reproduce the relation between stellar mass and halo mass from abundance matching, as well as the observed half-light size vs luminosity relation. The corresponding dissipationless simulations over-predict the V_{1/2}, recovering the problem known as too big to fail (TBTF). By contrast, the NIHAO simulations have expanded dark matter haloes, and provide an excellent match to the distribution of V_{1/2} for galaxies with L_V > 2 x 10^6 L_{sun}. For lower luminosities our simulations predict very little halo response, and tend to over predict the observed circular velocities. In the context of LCDM, this could signal the increased stochasticity of star formation in haloes below M_{halo} \sim 10^{10} M_{sun}, or the role of environmental effects. Thus, haloes that are "too big to fail", do not fail LCDM, but haloes that are "too small to pass" (the galaxy formation threshold) provide a future test of LCDM. 6 pages, 3 figures, accepted to MNRAS letters

  • Publication . Preprint . Article . 2017
    Open Access English
    Authors: 
    Shalev-Shwartz, Shai; Shamir, Ohad; Shammah, Shaked;

    In recent years, Deep Learning has become the go-to solution for a broad range of applications, often outperforming state-of-the-art. However, it is important, for both theoreticians and practitioners, to gain a deeper understanding of the difficulties and limitations associated with common approaches and algorithms. We describe four types of simple problems, for which the gradient-based algorithms commonly used in deep learning either fail or suffer from significant difficulties. We illustrate the failures through practical experiments, and provide theoretical insights explaining their source, and how they might be remedied.

  • Publication . Article . Preprint . 2017 . Embargo End Date: 01 Jan 2017
    Open Access
    Authors: 
    Rapaport, Ariel;
    Publisher: arXiv
    Project: EC | FRACTALSANDMETRICNT (306494)

    We show there exists a constant $0

  • Publication . Article . Preprint . 2017
    Open Access English
    Authors: 
    Vladimir Gol'dshtein; Valerii Pchelintsev; Alexander Ukhlov;
    Country: Russian Federation

    In this paper we apply estimates of the norms of Sobolev extension operators to the spectral estimates of of the first nontrivial Neumann eigenvalue of the Laplace operator in non-convex extension domains. As a consequence we obtain a connection between resonant frequencies of free membranes and the smallest-circle problem (initially proposed by J.~J.~Sylvester in 1857). 12 pages

  • Publication . Article . Preprint . 1996
    Open Access
    Authors: 
    Paul Biran;
    Publisher: Springer Science and Business Media LLC

    We discuss closed symplectic 4-manifolds which admit full symplectic packings by $N$ equal balls for large $N$'s. We give a homological criterion for recognizing such manifolds. As a corollary we prove that ${\Bbb C}P^2$ can be fully packed by $N$ equal balls for every $N\geq 9$. Comment: 12 pages, written in Amslatex. (A few mathematical typos fixed)

  • Publication . Conference object . Preprint . Article . Contribution for newspaper or weekly magazine . 2017 . Embargo End Date: 01 Jan 2016
    Open Access
    Authors: 
    Kashyap Thimmaraju; Liron Schiff; Stefan Schmid;
    Publisher: arXiv
    Country: Denmark

    Software-defined networking is considered a promising new paradigm, enabling more reliable and formally verifiable communication networks. However, this paper shows that the separation of the control plane from the data plane, which lies at the heart of Software-Defined Networks (SDNs), introduces a new vulnerability which we call \emph{teleportation}. An attacker (e.g., a malicious switch in the data plane or a host connected to the network) can use teleportation to transmit information via the control plane and bypass critical network functions in the data plane (e.g., a firewall), and to violate security policies as well as logical and even physical separations. This paper characterizes the design space for teleportation attacks theoretically, and then identifies four different teleportation techniques. We demonstrate and discuss how these techniques can be exploited for different attacks (e.g., exfiltrating confidential data at high rates), and also initiate the discussion of possible countermeasures. Generally, and given today's trend toward more intent-based networking, we believe that our findings are relevant beyond the use cases considered in this paper. Comment: Accepted in EuroSP'17

  • Publication . Preprint . Article . 2012 . Embargo End Date: 01 Jan 2012
    Open Access
    Authors: 
    Inoue, Hiroyuki;
    Publisher: arXiv

    The progress in nanofabrication, measurement technology, and mesoscopic transport theory has been expanding the field of shot noise. Although a wave-packet approach to DC shot noise of independent electrons at finite temperature was offered as an intuitive alternative to the sophisticated theories, actual shot noise data often behave more complicated than the derived simple expression. For example, so-called effective charge can deviate from elementary electronic charge due to correlated tunnelings. Also, there are cases where one wishes to know the full spectrum of the shot noise. It will be of great use if a handy method for the shot noise in various experimental situations is available. In this article, a classical wave-packet approach to the shot noise is presented. The classical formulation provides a rigorous yet straightforward formalism to compute the full spectrum and, furthermore, clarifies the structure of Fano factor and effective charge. Additionally, the role of realistic detectors and an application to cross correlation measurements are also discussed. The present method can serve as an intuitive complement to the full quantum mechanical and field theoretical approaches.

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