231 research outputs found

    Photon number discrimination without a photon counter and its application to reconstructing non-Gaussian states

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    The non-linearity of a conditional photon-counting measurement can be used to `de-Gaussify' a Gaussian state of light. Here we present and experimentally demonstrate a technique for photon number resolution using only homodyne detection. We then apply this technique to inform a conditional measurement; unambiguously reconstructing the statistics of the non-Gaussian one and two photon subtracted squeezed vacuum states. Although our photon number measurement relies on ensemble averages and cannot be used to prepare non-Gaussian states of light, its high efficiency, photon number resolving capabilities, and compatibility with the telecommunications band make it suitable for quantum information tasks relying on the outcomes of mean values.Comment: 4 pages, 3 figures. Theory section expanded in response to referee comment

    A Scalable, Self-Analyzing Digital Locking System for use on Quantum Optics Experiments

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    Digital control of optics experiments has many advantages over analog control systems, specifically in terms of scalability, cost, flexibility, and the integration of system information into one location. We present a digital control system, freely available for download online, specifically designed for quantum optics experiments that allows for automatic and sequential re-locking of optical components. We show how the inbuilt locking analysis tools, including a white-noise network analyzer, can be used to help optimize individual locks, and verify the long term stability of the digital system. Finally, we present an example of the benefits of digital locking for quantum optics by applying the code to a specific experiment used to characterize optical Schrodinger cat states.Comment: 7 pages, 5 figure

    Demonstrating various quantum effects with two entangled laser beams

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    We report on the preparation of entangled two mode squeezed states of yet unseen quality. Based on a measurement of the covariance matrix we found a violation of the Reid and Drummond EPR-criterion at a value of only 0.36\pm0.03 compared to the threshold of 1. Furthermore, quantum state tomography was used to extract a single photon Fock state solely based on homodyne detection, demonstrating the strong quantum features of this pair of laser-beams. The probability for a single photon in this ensemble measurement exceeded 2/3

    Gravitational radiation from a particle in circular orbit around a black hole. V. Black-hole absorption and tail corrections

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    A particle of mass ÎŒ\mu moves on a circular orbit of a nonrotating black hole of mass MM. Under the restrictions ÎŒ/Mâ‰Ș1\mu/M \ll 1 and vâ‰Ș1v \ll 1, where vv is the orbital velocity, we consider the gravitational waves emitted by such a binary system. We calculate E˙\dot{E}, the rate at which the gravitational waves remove energy from the system. The total energy loss is given by E˙=E˙∞+E˙H\dot{E} = \dot{E}^\infty + \dot{E}^H, where E˙∞\dot{E}^\infty denotes that part of the gravitational-wave energy which is carried off to infinity, while E˙H\dot{E}^H denotes the part which is absorbed by the black hole. We show that the black-hole absorption is a small effect: E˙H/E˙≃v8\dot{E}^H/\dot{E} \simeq v^8. We also compare the wave generation formalism which derives from perturbation theory to the post-Newtonian formalism of Blanchet and Damour. Among other things we consider the corrections to the asymptotic gravitational-wave field which are due to wave-propagation (tail) effects.Comment: ReVTeX, 17 page

    One-loop Quantum Gravity in Schwarzschild Spacetime

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    The quantum theory of linearized perturbations of the gravitational field of a Schwarzschild black hole is presented. The fundamental operators are seen to be the perturbed Weyl scalars ι˙0\dot\Psi_0 and ι˙4\dot\Psi_4 associated with the Newman-Penrose description of the classical theory. Formulae are obtained for the expectation values of the modulus squared of these operators in the Boulware, Unruh and Hartle-Hawking quantum states. Differences between the renormalized expectation values of both ∣ι˙0∣2\bigl| \dot\Psi_0 \bigr|^2 and ∣ι˙4∣2\bigl| \dot\Psi_4 \bigr|^2 in the three quantum states are evaluated numerically.Comment: 39 pages, 11 Postscript figures, using revte

    Holographic Derivation of Kerr-Newman Scattering Amplitudes for General Charge and Spin

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    Near-superradiant scattering of charged scalars and fermions by a near-extreme Kerr-Newman black hole and photons and gravitons by a near-extreme Kerr black hole are computed as certain Fourier transforms of correlators in a two-dimensional conformal field theory. The results agree with the classic spacetime calculations from the 1970s, thereby providing good evidence for a conjectured Kerr-Newman/CFT correspondence.Comment: 22 page

    Modification of cell surface properties of Pseudomonas alcaligenes S22 during hydrocarbon biodegradation

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    Biodegradation of water insoluble hydrocarbons can be significantly increased by the addition of natural surfactants one. Very promising option is the use of saponins. The obtained results indicated that in this system, after 21 days, 92% biodegradation of diesel oil could be achieved using Pseudomonas alcaligenes. No positive effect on the biodegradation process was observed using synthetic surfactant Triton X-100. The kind of carbon source influences the cell surface properties of microorganisms. Modification of the surface cell could be observed by control of the sedimentation profile. This analytical method is a new approach in microbiological analysis

    NCSX Construction Progress and Research Plans

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    Stellarators use 3D plasma and magnetic field shaping to produce a steady-state disruption-free magnetic confinement configuration. Compact stellarators have additional attractive properties — quasi-symmetric magnetic fields and low aspect ratio. The National Compact Stellarator Experiment (NCSX) is being constructed at the Princeton Plasma Physics Laboratory (PPPL) in partnership with the Oak Ridge National Laboratory (ORNL) to test the physics of a high-beta compact stellarator with a lowripple, tokamak-like magnetic configuration. The engineering challenges of NCSX stem from its complex geometry requirements. These issues are addressed in the construction project through manufacturing R&D and system engineering. As a result, the fabrication of the coil winding forms and vacuum vessel are proceeding in industry without significant technical issues, and preparations for winding the coils at PPPL are in place. Design integration, analysis, and dimensional control are functions provided by system engineering to ensure that the finished product will satisfy the physics requirements, especially accurate realization of the specified coil geometries. After completion of construction in 2009, a research program to test the expected physics benefits will start
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