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Jun 28, 2018
06/18

by
Krishna Kumar Sabapathy

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We introduce a quantum-optical notion of nonclassicality that we call as the process output nonclassicality for multimode quantum channels. The motivation comes from an information-theoretic point of view and the emphasis is on the output states of a channel. We deem a channel to be `classical' if its outputs are always classical irrespective of the input, i.e., if the channel is nonclassicality breaking, and nonclassical otherwise. Our condition is stronger than the one considered by...

Topics: Quantum Physics, Optics, Physics

Source: http://arxiv.org/abs/1506.06706

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5.0

Jun 27, 2018
06/18

by
Yuki Susa

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We investigate the weak measurement experiment demonstrated by Ritchie et al. [N. W. M. Ritchie, J. G. Story, and R. G. Hulet, Phys. Rev. Lett. 66, 1107 (1991)] from the viewpoint of the statistical hypothesis testing for the weak-value amplification proposed by Susa and Tanaka [Y. Susa and S. Tanaka, Phys. Rev. A 92, 012112 (2015)]. We conclude that the weak-value amplification is a better method to determine whether the crystal used in the experiment is birefringent than the measurement...

Topic: Quantum Physics

Source: http://arxiv.org/abs/1505.07199

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4.0

Jun 26, 2018
06/18

by
Toyohiro Tsurumaru; Tsubasa Ichikawa

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The squash operation, or the squashing model, is a useful mathematical tool for proving the security of quantum key distribution systems using practical (i.e., non-ideal) detectors. At the present, however, this method can only be applied to a limited class of detectors, such as the threshold detector of the Bennett-Brassard 1984 type. In this paper we generalize this method to include multi-partite measurements, such that it can be applied to a wider class of detectors. We demonstrate the...

Topic: Quantum Physics

Source: http://arxiv.org/abs/1502.04802

2
2.0

Jun 27, 2018
06/18

by
M. R. Feyereisen

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Weak values are average quantities,therefore investigating their associated variance is crucial in understanding their place in quantum mechanics. We develop the concept of a position-postselected weak variance of momentum as cohesively as possible, building primarily on material from Moyal (Mathematical Proceedings of the Cambridge Philosophical Society, Cambridge University Press, Cambridge, 1949) and Sonego (Found Phys 21(10):1135, 1991) . The weak variance is defined in terms of the Wigner...

Topics: Quantum Physics, Data Analysis, Statistics and Probability, Physics

Source: http://arxiv.org/abs/1503.07309

2
2.0

Jun 26, 2018
06/18

by
Daniel Chung; Leon Chan; Michael MacDonald; Nicholas Hutchins; Andrew Ooi

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We describe a fast direct numerical simulation (DNS) method that promises to directly characterise the hydraulic roughness of any given rough surface, from the hydraulically smooth to the fully rough regime. The method circumvents the unfavourable computational cost associated with simulating high-Reynolds-number flows by employing minimal-span channels (Jimenez & Moin 1991). Proof-of-concept simulations demonstrate that flows in minimal-span channels are sufficient for capturing the...

Topics: Physics, Fluid Dynamics

Source: http://arxiv.org/abs/1502.07043

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Jun 27, 2018
06/18

by
Sarita Rosenstock; James Owen Weatherall

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A classic result in the foundations of Yang-Mills theory, due to J. W. Barrett ["Holonomy and Path Structures in General Relativity and Yang-Mills Theory." Int. J. Th. Phys. 30(9), (1991)], establishes that given a "generalized" holonomy map from the space of piece-wise smooth, closed curves based at some point of a manifold to a Lie group, there exists a principal bundle with that group as structure group and a principal connection on that bundle such that the holonomy map...

Topics: Physics, High Energy Physics - Theory, Mathematics, History and Philosophy of Physics, Mathematical...

Source: http://arxiv.org/abs/1504.02401

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Jun 26, 2018
06/18

by
Matthias Mauch; Robert M. MacCallum; Mark Levy; Armand M. Leroi

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In modern societies, cultural change seems ceaseless. The flux of fashion is especially obvious for popular music. While much has been written about the origin and evolution of pop, most claims about its history are anecdotal rather than scientific in nature. To rectify this we investigate the US Billboard Hot 100 between 1960 and 2010. Using Music Information Retrieval (MIR) and text-mining tools we analyse the musical properties of ~17,000 recordings that appeared in the charts and...

Topics: Sound, Physics, Physics and Society, Computing Research Repository

Source: http://arxiv.org/abs/1502.05417

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0.0

Jun 28, 2018
06/18

by
S. Vantieghem; D. Cébron; J. Noir

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Motivated by understanding the liquid core dynamics of tidally deformed planets and moons, we present a study of incompressible flow driven by latitudinal libration within rigid triaxial ellipsoids. We first derive a laminar solution for the inviscid equations of motion under the assumption of uniform vorticity flow. This solution exhibits a res- onance if the libration frequency matches the frequency of the spin-over inertial mode. Furthermore, we extend our model by introducing a reduced...

Topics: Fluid Dynamics, Physics

Source: http://arxiv.org/abs/1512.08281

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0.0

Jun 28, 2018
06/18

by
Jānis Priede; Thomas Arlt; Leo Bühler

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This study is concerned with numerical linear stability analysis of liquid metal flow in a square duct with thin electrically conducting walls subject to a uniform transverse magnetic field. We derive an asymptotic solution for the base flow which is valid not only for high but also moderate magnetic fields. This solution shows that for low wall conductance ratios $c\ll1,$ an extremely strong magnetic field with the Hartmann number $Ha\sim c^{-4}$ is required to attain the asymptotic flow...

Topics: Fluid Dynamics, Physics

Source: http://arxiv.org/abs/1510.09222

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5.0

Jun 26, 2018
06/18

by
Andrew D. Bragg; Peter J. Ireland; Lance R. Collins

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`Preferential concentration' (\emph{Phys. Fluids} \textbf{A3}:1169--78, 1991) refers to the clustering of inertial particles in the high-strain, low-rotation regions of turbulence. The `centrifuge mechanism' of Maxey (\emph{J. Fluid Mech.} \textbf{174}:441--65, 1987) appears to explain this phenomenon. In a recent paper, Bragg \& Collins (\emph{New J. Phys.} \textbf{16}:055013, 2014) showed that the centrifuge mechanism is dominant only in the regime ${St\ll1}$, where $St$ is the Stokes...

Topics: Fluid Dynamics, Physics

Source: http://arxiv.org/abs/1501.03842

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2.0

Jun 28, 2018
06/18

by
T. S. Eaves; C. P. Caulfield

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We identify `minimal seeds' for turbulence, i.e. initial conditions of the smallest possible total perturbation energy density $E_c$ that trigger turbulence from the laminar state, in stably stratified plane Couette flow using the `direct-adjoint-looping' (DAL) method for finding nonlinear optimal perturbations that optimise the time averaged total dissipation of energy in the flow. These minimal seeds are located adjacent to the edge manifold, the manifold in state space that separates...

Topics: Fluid Dynamics, Physics

Source: http://arxiv.org/abs/1509.06334

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2.0

Jun 26, 2018
06/18

by
Bernard S. Kay; Umberto Lupo

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We conjecture that (when the notion of Hadamard state is suitably adapted) there is no isometry-invariant Hadamard state for the massive or massless covariant Klein-Gordon equation defined on the region of the Kruskal spacetime to the left of a surface of constant Schwarzschild radius in the right Schwarzschild wedge when Dirichlet boundary conditions are put on that surface. We also prove that, with a suitable definition for 'boost-invariant Hadamard state' (which we call 'strongly...

Topics: High Energy Physics - Theory, Mathematics, General Relativity and Quantum Cosmology, Mathematical...

Source: http://arxiv.org/abs/1502.06582

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4.0

Jun 27, 2018
06/18

by
A. Araujo; H. Jennen; J. G. Pereira; A. C. Sampson; L. L. Savi

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As quotient spaces, Minkowski and de Sitter are fundamental, non-gravitational spacetimes for the construction of physical theories. When general relativity is constructed on a de Sitter spacetime, the usual Riemannian structure is replaced by a more general structure called de Sitter-Cartan geometry. In the contraction limit of an infinite cosmological term, the de Sitter-Cartan spacetime reduces to a singular, flat, conformal invariant four-dimensional cone spacetime, in which our ordinary...

Topics: General Relativity and Quantum Cosmology, High Energy Physics - Theory

Source: http://arxiv.org/abs/1503.05005