1,655 research outputs found
Coherent energy migration in solids: Determination of the average coherence length in one‐dimensional systems using tunable dye lasers
The coherent nature of energy propagation in solids at low temperatures was established from the time resolved response of the crystal to short optical pulses obtained from a dye laser (pumped by a nitrogen gas laser). The trapping and detrapping of the energy by shallow defects (x traps) was evident in the spectra and enabled us to extract the coherence length: l≳700 Å=186 molecules for the one‐dimensional triplet excitons of 1,2,4,5‐tetrachlorobenzene crystals at T<4.2° K. This length which clearly exceeds the stochastic random walk limit is related to the thermalization mechanisms in this coupled exciton–trap system, and its magnitude supports the notion that exciton–phonon coupling is responsible for the loss of coherence on very long molecular chains (trap concentration is 1/256 000)
Low-Frequency Line Shapes in Guided Acoustic-Wave Brillouin Scattering
Guided acoustic‐wave Brillouin scattering (GAWBS) measurements were performed on 20‐cm lengths of optical fibers with particular attention focused on the lowest lying resonance. In 125‐μm‐diam silica fibers, this resonance was observed to occur at ~22 MHz and have a line shape which varied erratically from sample to sample. Significant line shape fluctuations were evident even between sequential samples from the same fiber spool. We speculate that the observed effects are attributable to 0.01-0.1 μm distributed geometric deviations from a perfect cylinder
A Template Analysis of Intimate Partner Violence Survivors’ Experiences of Animal Maltreatment: Implications for Safety Planning and Intervention
This study explores the intersection of intimate partner violence (IPV) and animal cruelty in an ethnically diverse sample of 103 pet-owning IPV survivors recruited from community-based domestic violence programs. Template analysis revealed five themes: (a) Animal Maltreatment by Partner as a Tactic of Coercive Power and Control, (b) Animal Maltreatment by Partner as Discipline or Punishment of Pet, (c) Animal Maltreatment by Children, (d) Emotional and Psychological Impact of Animal Maltreatment Exposure, and (e) Pets as an Obstacle to Effective Safety Planning. Results demonstrate the potential impact of animal maltreatment exposure on women and child IPV survivors’ health and safety
Demonstration of Robust Quantum Gate Tomography via Randomized Benchmarking
Typical quantum gate tomography protocols struggle with a self-consistency
problem: the gate operation cannot be reconstructed without knowledge of the
initial state and final measurement, but such knowledge cannot be obtained
without well-characterized gates. A recently proposed technique, known as
randomized benchmarking tomography (RBT), sidesteps this self-consistency
problem by designing experiments to be insensitive to preparation and
measurement imperfections. We implement this proposal in a superconducting
qubit system, using a number of experimental improvements including
implementing each of the elements of the Clifford group in single `atomic'
pulses and custom control hardware to enable large overhead protocols. We show
a robust reconstruction of several single-qubit quantum gates, including a
unitary outside the Clifford group. We demonstrate that RBT yields physical
gate reconstructions that are consistent with fidelities obtained by randomized
benchmarking
Coherent energy migration in solids: Determination of the average coherence length in one-dimensional systems using tunable dye lasers
Anisotropy and oblique total transmission at a planar negative-index interface
We show that a class of negative index (n) materials has interesting
anisotropic optical properties, manifest in the effective refraction index that
can be positive, negative, or purely imaginary under different incidence
conditions. With dispersion taken into account, reflection at a planar
negative-index interface exhibits frequency selective total oblique
transmission that is distinct from the Brewster effect.
Finite-difference-time-domain simulation of realistic negative-n structures
confirms the analytic results based on effective indices.Comment: to appear in Phys. Rev.
Refraction at Media with Negative Refractive Index
We show that an electromagnetic (EM) wave undergoes negative refraction at
the interface between a positive and negative refractive index material. Finite
difference time domain (FDTD) simulations are used to study the time evolution
of an EM wave as it hits the interface. The wave is trapped temporarily at the
interface and after a long time, the wave front moves eventually in the
negative direction. This explains why causality and speed of light are not
violated in spite of the negative refraction always present in a negative index
material.Comment: 5 pages, 4 figures, submitted to Phys. Rev. Let
Insights into the microbiome of breast implants and periprosthetic tissue in breast implant-associated anaplastic large cell lymphoma
Comparison of a 2-Layer Electric Fence and a Single Strand Electric Fence in Mitigating Browsing of Impatiens by White-Tailed Deer
The objective of this study was to evaluate two electric fence configurations in minimizing damage to impatiens (Impatiens walleriana) by white-tailed deer (Odocoileus virginianus). Each of 3 sites consisted of 3 plots (3mx3m), containing 16, evenly spaced impatiens planted on the perimeter of each plot. Plots within each site had a control, single strand and 2-layered electric fence. Control plots had no fencing. Single strand plots had one electrified wire attached to posts at 40 cm height, surrounding the plot. Two-layered electric fence had energized wire attached to posts at 25 cm and 60 cm height, on the perimeter of the plot. A second, single electrified wire was attached to posts at 25 cm height, 1 m to the exterior of the two strand fence. Eight plants within each plot was photographed weekly for 3-weeks. The percentage of total pixels containing plant material in each photo was used to determine changes in plant growth. The percentage of pixels containing impatiens plants was lower (
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