2,052 research outputs found

    Violation of Bell's inequality for phase singular beams

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    We have considered optical beams with phase singularity and experimentally verified that these beams, although being classical, have properties of two mode entanglement in quantum states. We have observed the violation of Bell's inequality for continuous variables using the Wigner distribution function (WDF) proposed by Chowdhury et al. [Phys. Rev. A \textbf{88}, 013830 (2013)]. Our experiment establishes a new form of Bell's inequality in terms of the WDF which can be used for classical as well as quantum systems.Comment: 7 pages, 9 figures and 1 tabl

    Non equilibrium statistical physics with fictitious time

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    Problems in non equilibrium statistical physics are characterized by the absence of a fluctuation dissipation theorem. The usual analytic route for treating these vast class of problems is to use response fields in addition to the real fields that are pertinent to a given problem. This line of argument was introduced by Martin, Siggia and Rose. We show that instead of using the response field, one can, following the stochastic quantization of Parisi and Wu, introduce a fictitious time. In this extra dimension a fluctuation dissipation theorem is built in and provides a different outlook to problems in non equilibrium statistical physics.Comment: 4 page

    Approach to equilibrium in adiabatically evolving potentials

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    For a potential function (in one dimension) which evolves from a specified initial form Vi(x)V_{i}(x) to a different Vf(x)V_{f}(x) asymptotically, we study the evolution, in an overdamped dynamics, of an initial probability density to its final equilibeium.There can be unexpected effects that can arise from the time dependence. We choose a time variation of the form V(x,t)=Vf(x)+(ViVf)eλtV(x,t)=V_{f}(x)+(V_{i}-V_{f})e^{-\lambda t}. For a Vf(x)V_{f}(x), which is double welled and a Vi(x)V_{i}(x) which is simple harmonic, we show that, in particular, if the evolution is adiabatic, the results in a decrease in the Kramers time characteristics of Vf(x)V_{f}(x). Thus the time dependence makes diffusion over a barrier more efficient. There can also be interesting resonance effects when Vi(x)V_{i}(x) and Vf(x)V_{f}(x) are two harmonic potentials displaced with respect to each other that arise from the coincidence of the intrinsic time scale characterising the potential variation and the Kramers time.Comment: This paper contains 5 page

    Inelastic scattering of protons from 6,8^{6,8}He and 7,11^{7,11}Li in a folding model approach

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    The proton-inelastic scattering from 6,8^{6,8}He and 7,11^{7,11}Li nuclei are studied in a folding model approach. A finite-range, momentum, density and isospin dependent nucleon-nucleon interaction (SBM) is folded with realistic density distributions of the above nuclei. The renormalization factors NR_R and NI_I on the real and volume imaginary part of the folded potentials are obtained by analyzing the respective elastic scattering data and kept unaltered for the inelastic analysis at the same energy. The form factors are generated by taking derivatives of the folded potentials and therefore required renormalizations. The β\beta values are extracted by fitting the p + 6,8^{6,8}He,7,11^{7,11}Li inelastic angular distributions. The present analysis of p + 8^8He inelastic scattering to the 3.57 MeV excited state, including unpublished forward angle data (RIKEN) confirms L = 2 transition. Similar analysis of the p + 6^6He inelastic scattering angular distribution leading to the 1.8 MeV (L = 2) excited state fails to satisfactorily reproduce the data.Comment: one LaTeX file, five PostScript figure

    Nonlinear Mode Coupling and Internal Resonances in MoS2 Nanoelectromechanical System

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    Atomically thin two dimensional (2D) layered materials have emerged as a new class of material for nanoelectromechanical systems (NEMS) due to their extraordinary mechanical properties and ultralow mass density. Among them, graphene has been the material of choice for nanomechanical resonator. However, recent interest in 2D chalcogenide compounds has also spurred research in using materials such as MoS2 for NEMS applications. As the dimensions of devices fabricated using these materials shrink down to atomically thin membrane, strain and nonlinear effects have become important. A clear understanding of nonlinear effects and the ability to manipulate them is essential for next generation sensors. Here we report on all electrical actuation and detection of few layers MoS2 resonator. The ability to electrically detect multiple modes and actuate the modes deep into nonlinear regime enables us to probe the nonlinear coupling between various vibrational modes. The modal coupling in our device is strong enough to detect three distinct internal resonances

    Modified Bethe-Weizsacker mass formula with isotonic shift and new driplines

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    Nuclear masses are calculated using the modified Bethe-Weizsacker mass formula in which the isotonic shifts have been incorporated. The results are compared with the improved liquid drop model with isotonic shift. Mass excesses predicted by this method compares well with the microscopic-macroscopic model while being much more simple. The neutron and proton drip lines have been predicted using this modified Bethe-Weizsacker mass formula with isotonic shifts.Comment: 9 pages including 2 figure
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