2,070 research outputs found
State v. Roberts: A Persuasive but Unsupported Position
The Ohio Supreme Court recently held in State v. Roberts that when a witness is unavailable at the trial of a criminal defendant, the state may not introduce the witness\u27 preliminary hearing testimony into evidence unless he had been cross-examined at the preliminary hearing. The court found that the defendant, Roberts, had been denied his right to confront an adverse witness when the trial court admitted the preliminary hearing testimony of a witness who was not present at trial, and held that mere opportunity to cross-examine at a preliminary hearing, unexercised, did not satisfy the demands of the Confrontation Clause of the sixth amendment. Section I of this Note provides the facts of the case, the trial court and appellate decisions, and the Ohio Supreme Court’s decision. Section II delves into the Court’s decision on the preliminary hearing testimony in relation to the Confrontation Clause. Section III explains why the majority opinion is problematic, and Section IV provides an alternative rationale for the Court to use instead
Integrated multi vector vortex beam generator
A novel method to generate and manipulate vector vortex beams in an
integrated, ring resonator based geometry is proposed. We show numerically that
a ring resonator, with an appropriate grating, addressed by a vertically
displaced access waveguide emits a complex optical field. The emitted beam
possesses a specific polarization topology, and consequently a transverse
intensity profile and orbital angular momentum. We propose a combination of
several concentric ring resonators, addressed with different bus guides, to
generate arbitrary orbital angular momentum qudit states, which could
potentially be used for classical and quantum communications. Finally, we
demonstrate numerically that this device works as an orbital angular momentum
sorter with an average cross-talk of -10 dB between different orbital angular
momentum channels.Comment: 8 pages, 7 figure
Robust Quantum Error Correction via Convex Optimization
We present a semidefinite program optimization approach to quantum error
correction that yields codes and recovery procedures that are robust against
significant variations in the noise channel. Our approach allows us to optimize
the encoding, recovery, or both, and is amenable to approximations that
significantly improve computational cost while retaining fidelity. We
illustrate our theory numerically for optimized 5-qubit codes, using the
standard [5,1,3] code as a benchmark. Our optimized encoding and recovery
yields fidelities that are uniformly higher by 1-2 orders of magnitude against
random unitary weight-2 errors compared to the [5,1,3] code with standard
recovery. We observe similar improvement for a 4-qubit decoherence-free
subspace code.Comment: 4 pages, including 3 figures. v2: new example
Imaging with a small number of photons
Low-light-level imaging techniques have application in many diverse fields,
ranging from biological sciences to security. We demonstrate a single-photon
imaging system based on a time-gated inten- sified CCD (ICCD) camera in which
the image of an object can be inferred from very few detected photons. We show
that a ghost-imaging configuration, where the image is obtained from photons
that have never interacted with the object, is a useful approach for obtaining
images with high signal-to-noise ratios. The use of heralded single-photons
ensures that the background counts can be virtually eliminated from the
recorded images. By applying techniques of compressed sensing and associated
image reconstruction, we obtain high-quality images of the object from raw data
comprised of fewer than one detected photon per image pixel.Comment: 9 pages, 4 figure
Atlas of Lobster Anatomy and Histology
This is a histological atlas of the most common organs and tissues found in the American lobster, Homarus americanus. The atlas contains photomicrographs from histological sections of healthy tissues. The atlas contains pictures of tissues that are readily observed in dissection and several that are commonly affected by diseases. It is not a complete atlas. Several organs are not covered, notably the brain, ventral nerve ganglion, sensory organs, and organs associated with molting
Compressive Object Tracking using Entangled Photons
We present a compressive sensing protocol that tracks a moving object by
removing static components from a scene. The implementation is carried out on a
ghost imaging scheme to minimize both the number of photons and the number of
measurements required to form a quantum image of the tracked object. This
procedure tracks an object at low light levels with fewer than 3% of the
measurements required for a raster scan, permitting us to more effectively use
the information content in each photon.Comment: 10 pages, 4 figure
Optical spin-to-orbital angular momentum conversion in ultra-thin metasurfaces with arbitrary topological charges
Orbital angular momentum associated with the helical phase-front of optical
beams provides an unbounded \qo{space} for both classical and quantum
communications. Among the different approaches to generate and manipulate
orbital angular momentum states of light, coupling between spin and orbital
angular momentum allows a faster manipulation of orbital angular momentum
states because it depends on manipulating the polarisation state of light,
which is simpler and generally faster than manipulating conventional orbital
angular momentum generators. In this work, we design and fabricate an
ultra-thin spin-to-orbital angular momentum converter, based on plasmonic
nano-antennas and operating in the visible wavelength range that is capable of
converting spin to an arbitrary value of OAM . The nano-antennas are
arranged in an array with a well-defined geometry in the transverse plane of
the beam, possessing a specific integer or half-integer topological charge .
When a circularly polarised light beam traverses this metasurface, the output
beam polarisation switches handedness and the OAM changes in value by per photon. We experimentally demonstrate values ranging
from to with conversion efficiencies of . Our
ultra-thin devices are integratable and thus suitable for applications in
quantum communications, quantum computations and nano-scale sensing.Comment: 4 pages, 3 figures - submitted
Properties Of Microwave Cavities Containing Magnetic Resonant Samples
Properties of TE011 cylindrical, microwave cavities containing cylindrical samples of various radii and dielectric constants are calculated. The properties considered are the resonant frequency, quality factor (Q), relevant magnetic filling factor for spin transitions (ε), and a signal sensitivity factor (Qε) for a lossless sample. Sample sizes range from zero radius to full cavity radius with some experimental data on less than full length samples. The choice of dielectric constants ranges from one to sixteen. The data are presented in dimensionless form since they will be of use to other ESR experimentalists. It is shown that use of large samples is undesirable even if they are lossless. Furthermore, elongated cavities (D/L ratios less than one) are to be preferred over shortened cavities. © 1973 The American Institute of Physics
Host-Switching Does not Circumvent the Ni-based Defence of the Ni hyperaccumulator \u3ci\u3eStreptanthus polygaloides\u3c/i\u3e (Brassicaceae)
Elevated tissue concentrations of metals have been shown to defend metal-hyperaccumulating plants against both herbivores and pathogens. Tolerance of metal-based defences presents a challenge to herbivores, because heavy metals cannot be degraded or metabolized. One strategy that herbivores can employ to counter high-metal defences is dietary dilution, or host switching. Highly mobile herbivores are most likely to use this strategy, but less mobile lepidopteran larvae can also Improve their performance on toxic hosts if early instar development occurs on more favourable hosts. We examined the effects of host switching on growth and survival of a generalist folivore. Specifically, we tested the hypothesis that early larval development on non-toxic hosts could improve larval performance of the beet armyworm, Spodoptera exigua, an high-Ni Streptanthus polygaloides, a Ni hyperaccumulator. Initial larval performance (weight gain) was lowest for insects switched to high-N! hosts. Decreased initial larval performance was also noted for insects switched from lettuce to low-Ni S. polygaloides, but these larvae recovered quickly. Original host identity (lettuce or low-Ni S. polygaloides) did not affect subsequent larval performance. By day 8 of the feeding trials, all larvae switched to high-Ni hosts had died. We conclude that polyphagous Spodoptera larvae are unable to counter NI-based defences via host switching
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