106 research outputs found

    Quantum Nonlocality for a Mixed Entangled Coherent State

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    Quantum nonlocality is tested for an entangled coherent state, interacting with a dissipative environment. A pure entangled coherent state violates Bell's inequality regardless of its coherent amplitude. The higher the initial nonlocality, the more rapidly quantum nonlocality is lost. The entangled coherent state can also be investigated in the framework of 2Ă—22\times2 Hilbert space. The quantum nonlocality persists longer in 2Ă—22\times2 Hilbert space. When it decoheres it is found that the entangled coherent state fails the nonlocality test, which contrasts with the fact that the decohered entangled state is always entangled.Comment: 20 pages, 7 figures. To be published in J. Mod. Op

    Violation of Bell's inequality using classical measurements and non-linear local operations

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    We find that Bell's inequality can be significantly violated (up to Tsirelson's bound) with two-mode entangled coherent states using only homodyne measurements. This requires Kerr nonlinear interactions for local operations on the entangled coherent states. Our example is a demonstration of Bell-inequality violations using classical measurements. We conclude that entangled coherent states with coherent amplitudes as small as 0.842 are sufficient to produce such violations.Comment: 6 pages, 5 figures, to be published in Phys. Rev.

    Laser Tag - An Application of Infrared Communication

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    The purpose of this project is to design, build, and test laser tag system from the ground up. Much of the laser tag equipment that is available on the market right now use infrared technology to track and register “hits” between players. Our goal is to take this system and redesign it to shoot farther, be more energy efficient, and make it cheaper to produce

    Wigner Function Evolution of Quantum States in Presence of Self-Kerr Interaction

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    A Fokker-Planck equation for the Wigner function evolution in a noisy Kerr medium (χ(3)\chi^{(3)} non-linearity) is presented. We numerically solved this equation taking a coherent state as an initial condition. The dissipation effects are discussed. We provide examples of quantum interference, sub-Planck phase space structures, and Gaussian versus non-Gaussian dynamical evolution of the state. The results also apply to the description of a nanomechanical resonator with an intrinsic Duffing nonlinearity.Comment: 10 pages, 11 figure

    Quantum entanglement and Bell violation of two coupled cavity fields in dissipative environment

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    We study the quantum entanglement between two coupled cavities, in which one is initially prepared in a mesoscopic superposition state and the other is in the vacuum in dissipative environment and show how the entanglement between two cavities can arise in the dissipative environment. The dynamic behavior of the nonlocality for the system is also investigated.Comment: 12 pages, 5 figure

    Dynamics of Nonlocality for A Two-Mode Squeezed State in Thermal Environment

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    We investigate the time evolution of nonlocality for a two-mode squeezed state in the thermal environment. The initial two-mode pure squeezed state is nonlocal with a stronger nonlocality for a larger degree of squeezing. It is found that the larger the degree of initial squeezing is, the more rapidly the squeezed state loses its nonlocality. We explain this by the rapid destruction of quantum coherence for the strongly squeezed state.Comment: 5 pages, 3 figures, accepted to PR

    Mass Determination and Detection of the Onset of Chromospheric Activity for the Sub-Stellar Object in EF Eridani

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    EF Eri is a magnetic cataclysmic variable that has been in a low accretion state for the past nine years. Low state optical spectra reveal the underlying Zeeman-split white dwarf absorption lines. These features are used to determine a value of 13-14 MG as the white dwarf field strength. Recently, 5-7 years into the low state, Balmer and other emission lines have appeared in the optical. An analysis of the Hα\alpha emission line yields the first radial velocity solution for EF Eri, leading to a spectroscopic ephemeris for the binary and, using the best available white dwarf mass of 0.6M⊙{\odot}, a mass estimate for the secondary of 0.055M⊙{\odot}. For a white dwarf mass of 0.95M⊙{\odot}, the average for magnetic white dwarfs, the secondary mass increases to 0.087M⊙{\odot}. At EF Eri's orbital period of 81 minutes, this higher mass secondary could not be a normal star and still fit within the Roche lobe. The source of the Balmer and other emission lines is confirmed to be from the sub-stellar secondary and we argue that it is due to stellar activity. We compare EF Eri's emission line spectrum and activity behavior to that recently observed in AM Her and VV Pup and attributed to stellar activity. We explore observations and models originally developed for V471 Tau, for the RS CVn binaries, and for extra-solar planets. We conclude that irradiation of the secondary in EF Eri and similar systems is unlikely and, in polars, the magnetic field interaction between the two stars (with a possible tidal component) is a probable mechanism which would concentrate chromospheric activity on the secondary near the sub-stellar point of the white dwarf.Comment: 49 pages, 12 figures Accepted to ApJ (Main journal

    Opening the Gate to Money Market Fund Reform

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