18,061 research outputs found
A sensitive infrared imaging up converter and spatial coherence of atmospheric propagation
An infrared imaging technique based on the nonlinear interaction known as upconversion was used to obtain images of several astronomical objects in the 10 micrometer spectral region, and to demonstrate quantitatively the sharper images allowed for wavelengths beyond the visible region. The deleterious effects of atmospheric inhomogeneities on telescope resolution were studied in the infrared region using the technique developed. The low quantum efficiency of the device employed severely limited its usefulness as an astronomical detector
Employment Law--Sex Discrimination--Fourth Circuit Holds Private Employer\u27s Denial of Pregnancy-Related Disability Benefits Sex Discrimination and Violative of Title VII. Gilbert v. General Electric Co., 519 F.2d 661 (4th Cir. 1975), cert. granted, 423 U.S. 822 (1975)
LANDSAT range resource information system project, volume 1
There are no author-identified significant results in this report
Decorrelation of the topological charge in tempered Hybrid Monte Carlo simulations of QCD
We study the improvement of simulations of QCD with dynamical Wilson fermions
by combining the Hybrid Monte Carlo algorithm with parallel tempering. As an
indicator for decorrelation we use the topological charge.Comment: LATTICE99 (algorithms and machines
Quantum probabilities from quantum entanglement: Experimentally unpacking the Born rule
The Born rule, a foundational axiom used to deduce probabilities of events
from wavefunctions, is indispensable in the everyday practice of quantum
physics. It is also key in the quest to reconcile the ostensibly inconsistent
laws of the quantum and classical realms, as it confers physical significance
to reduced density matrices, the essential tools of decoherence theory.
Following Bohr's Copenhagen interpretation, textbooks postulate the Born rule
outright. However, recent attempts to derive it from other quantum principles
have been successful, holding promise for simplifying and clarifying the
quantum foundational bedrock. A major family of derivations is based on
envariance, a recently discovered symmetry of entangled quantum states. Here,
we identify and experimentally test three premises central to these
envariance-based derivations, thus demonstrating, in the microworld, the
symmetries from which the Born rule is derived. Further, we demonstrate
envariance in a purely local quantum system, showing its independence from
relativistic causality.Comment: 21 pages, 6 figures, 6 appendices - Submitted
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Optically mediated nonlinear quantum optomechanics
We consider theoretically the optomechanical interaction of several
mechanical modes with a single quantized cavity field mode for linear and
quadratic coupling. We focus specifically on situations where the optical
dissipation is the dominant source of damping, in which case the optical field
can be adiabatically eliminated, resulting in effective multimode interactions
between the mechanical modes. In the case of linear coupling, the coherent
contribution to the interaction can be exploited e.g. in quantum state swapping
protocols, while the incoherent part leads to significant modifications of cold
damping or amplification from the single-mode situation. Quadratic coupling can
result in a wealth of possible effective interactions including the analogs of
second-harmonic generation and four-wave mixing in nonlinear optics, with
specific forms depending sensitively on the sign of the coupling. The
cavity-mediated mechanical interaction of two modes is investigated in two
limiting cases, the resolved sideband and the Doppler regime. As an
illustrative application of the formal analysis we discuss in some detail a
two-mode system where a Bose-Einstein condensate is optomechanically linearly
coupled to the moving end mirror of a Fabry-P\'erot cavity.Comment: 11 pages, 8 figure
Capacity of nonlinear bosonic systems
We analyze the role of nonlinear Hamiltonians in bosonic channels.
We show that the information capacity as a function of the channel energy is
increased with respect to the corresponding linear case, although only when the
energy used for driving the nonlinearity is not considered as part of the
energetic cost and when dispersive effects are negligible.Comment: 6 pages, 3 figure
Mixed perturbative expansion: the validity of a model for the cascading
A new type of perturbative expansion is built in order to give a rigorous
derivation and to clarify the range of validity of some commonly used model
equations.
This model describes the evolution of the modulation of two short and
localized pulses, fundamental and second harmonic, propagating together in a
bulk uniaxial crystal with non-vanishing second order susceptibility
and interacting through the nonlinear effect known as ``cascading'' in
nonlinear optics.
The perturbative method mixes a multi-scale expansion with a power series
expansion of the susceptibility, and must be carefully adapted to the physical
situation. It allows the determination of the physical conditions under which
the model is valid: the order of magnitude of the walk-off, phase-mismatch,and
anisotropy must have determined values.Comment: arxiv version is already officia
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