1,445 research outputs found

    The Trilinear Hamiltonian: A Zero Dimensional Model of Hawking Radiation from a Quantized Source

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    We investigate a quantum parametric amplifier with dynamical pump mode, viewed as a zero-dimensional model of Hawking radiation from an evaporating black hole. The conditions are derived under which the spectrum of particles generated from vacuum fluctuations deviates from the thermal spectrum predicted for the conventional parametric amplifier. We find that significant deviations arise when the pump mode (black hole) has emitted nearly half of its initial energy into the signal (Hawking radiation) and idler (in-falling particle) modes. As a model of black hole dynamics, this finding lends support to the view that late-time Hawking radiation contains information about the quantum state of the black hole and is entangled with the black hole's quantum gravitational degrees of freedom.Comment: 18 pages, 6 figures, Submitted to New Journal of Physics focus issue: "Classical and Quantum Analogues for Gravitational Phenomena and Related Effects

    Pedagogical Perspectives on Counselor Education: An Autoethnographic Experience of Doctoral Student Development

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    There is minimal literature related to understanding what training factors contribute to the development of qualified counselor educators. Specifically, we wondered if counselor education doctoral students are effectively prepared for their roles as instructors. We chose an autoethnographic phenomenology method as a means for exploring the experiences of doctoral students’ pedagogical development in a doctoral instructional theory course. We sought to understand the essence of our experience through written reflection, photography, and group reflective processes. Analysis revealed the value we all obtained through the instructional theory course, experiential learning, and self-reflection, which contributed to increased self-efficacy as emerging counselor educators. The essence of our experience is described through seven descriptive themes—delineated as methods of coping and reinforcing. The results demonstrate the benefit of including an explicit pedagogical course in counselor education curriculums. © 2019: Anna Elliott, Beronica M. Salazar, Brittany M. Davis, Lynn Bohecker, Tiffany Nielson, Kirsten LaMantia, David M. Kleist, and Nova Southeastern University

    Exact limiting relation between the structure factors in neutron and x-ray scattering

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    The ratio of the static matter structure factor measured in experiments on coherent X-ray scattering to the static structure factor measured in experiments on neutron scattering is considered. It is shown theoretically that this ratio in the long-wavelength limit is equal to the nucleus charge at arbitrary thermodynamic parameters of a pure substance (the system of nuclei and electrons, where interaction between particles is pure Coulomb) in a disordered equilibrium state. This result is the exact relation of the quantum statistical mechanics. The experimental verification of this relation can be done in the long wavelength X-ray and neutron experiments.Comment: 7 pages, no figure

    High-fidelity simulations of CdTe vapor deposition from a new bond-order potential-based molecular dynamics method

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    CdTe has been a special semiconductor for constructing the lowest-cost solar cells and the CdTe-based Cd1-xZnxTe alloy has been the leading semiconductor for radiation detection applications. The performance currently achieved for the materials, however, is still far below the theoretical expectations. This is because the property-limiting nanoscale defects that are easily formed during the growth of CdTe crystals are difficult to explore in experiments. Here we demonstrate the capability of a bond order potential-based molecular dynamics method for predicting the crystalline growth of CdTe films during vapor deposition simulations. Such a method may begin to enable defects generated during vapor deposition of CdTe crystals to be accurately explored

    Three flavour Quark matter in chiral colour dielectric model

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    We investigate the properties of quark matter at finite density and temperature using the nonlinear chiral extension of Colour Dielectric Model (CCM). Assuming that the square of the meson fields devlop non- zero vacuum expectation value, the thermodynamic potential for interacting three flavour matter has been calculated. It is found that and and remain zero in the medium whereas changes in the medium. As a result, uu and dd quark masses decrease monotonically as the temperature and density of the quark matter is increased.In the present model, the deconfinement density and temperature is found to be lower compared to lattice results. We also study the behaviour of pressure and energy density above critical temperature.Comment: Latex file. 5 figures available on request. To appear in Phys. Rev.

    The exact Darwin Lagrangian

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    Darwin (1920) noted that when radiation can be neglected it should be possible to eliminate the radiation degrees-of-freedom from the action of classical electrodynamics and keep the discrete particle degrees-of-freedom only. Darwin derived his well known Lagrangian by series expansion in v/cv/c keeping terms up to order (v/c)2(v/c)^2. Since radiation is due to acceleration the assumption of low speed should not be necessary. A Lagrangian is suggested that neglects radiation without assuming low speed. It cures deficiencies of the Darwin Lagrangian in the ultra-relativistic regime.Comment: 2.5 pages, no figure

    Entanglement dynamics of two qubits under the influence of external kicks and Gaussian pulses

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    We have investigated the dynamics of entanglement between two spin-1/2 qubits that are subject to independent kick and Gaussian pulse type external magnetic fields analytically as well as numerically. Dyson time ordering effect on the dynamics is found to be important for the sequence of kicks. We show that "almost-steady" high entanglement can be created between two initially unentangled qubits by using carefully designed kick or pulse sequences

    Alternative Mathematical Technique to Determine LS Spectral Terms

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    We presented an alternative computational method for determining the permitted LS spectral terms arising from lNl^N electronic configurations. This method makes the direct calculation of LS terms possible. Using only basic algebra, we derived our theory from LS-coupling scheme and Pauli exclusion principle. As an application, we have performed the most complete set of calculations to date of the spectral terms arising from lNl^N electronic configurations, and the representative results were shown. As another application on deducing LS-coupling rules, for two equivalent electrons, we deduced the famous Even Rule; for three equivalent electrons, we derived a new simple rule.Comment: Submitted to Phys. Rev.
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