5,747 research outputs found
Role of many-body entanglement in decoherence processes
A pure state decoheres into a mixed state as it entangles with an
environment. When an entangled two-mode system is embedded in a thermal
environment, however, each mode may not be entangled with its environment by
their simple linear interaction. We consider an exactly solvable model to study
the dynamics of a total system, which is composed of an entangled two-mode
system and a thermal environment, and also an array of infinite beam splitters.
It is shown that many-body entanglement of the system and the environment plays
a crucial role in the process of disentangling the system.Comment: 4 pages, 1 figur
Biomolecular sensing using surface micromachined silicon plates
Micromachined sensors to detect surface stress changes associated with interactions between an immobilized chemically selective receptor and a target analyte are presented. The top isolated sensing surface of a free-standing silicon plate is prepared with a thin Au layer, followed by a covalent attachment of chemical or biomolecule forming a chemically-selective surface. Surface stress changes in air are measured capacitively due to the formation of an alkanethiol self-assembled monolayer (SAM). Detection of biomolecular binding in liquid samples is measured optically using the streptavidin-biotin complex and AM. tuberculosis antigen-antibody system used for clinical tuberculosis (TB) diagnosis
Efficient Quantum Computation using Coherent States
Universal quantum computation using optical coherent states is studied. A
teleportation scheme for a coherent-state qubit is developed and applied to
gate operations. This scheme is shown to be robust to detection inefficiency.Comment: 6 pages, 5 figures, extended and modified (in print, PRA
Exactly soluble model for self-gravitating D-particles with the wormhole
We consider D-particles coupled to the CGHS dilaton gravity and obtain the
exact wormhole geometry and trajectories of D-particles by introducing the
exotic matter. The initial static wormhole background is not stable after
infalling D-particles due to the classical backreaction of the geometry so that
the additional exotic matter source should be introduced for the stability.
Then, the traversable wormhole geometry naturally appears and the D-particles
can travel through it safely. Finally, we discuss the dynamical evolution of
the wormhole throat and the massless limit of D-particles.Comment: 16 pages, 3 figures, revte
Generation of entangled coherent states via cross phase modulation in a double electromagnetically induced transparency regime
The generation of an entangled coherent state is one of the most important
ingredients of quantum information processing using coherent states. Recently,
numerous schemes to achieve this task have been proposed. In order to generate
travelling-wave entangled coherent states, cross phase modulation, optimized by
optical Kerr effect enhancement in a dense medium in an electromagnetically
induced transparency (EIT) regime, seems to be very promising. In this
scenario, we propose a fully quantized model of a double-EIT scheme recently
proposed [D. Petrosyan and G. Kurizki, {\sl Phys. Rev. A} {\bf 65}, 33833
(2002)]: the quantization step is performed adopting a fully Hamiltonian
approach. This allows us to write effective equations of motion for two
interacting quantum fields of light that show how the dynamics of one field
depends on the photon-number operator of the other. The preparation of a
Schr\"odinger cat state, which is a superposition of two distinct coherent
states, is briefly exposed. This is based on non-linear interaction via
double-EIT of two light fields (initially prepared in coherent states) and on a
detection step performed using a beam splitter and two photodetectors.
In order to show the entanglement of a generated entangled coherent state, we
suggest to measure the joint quadrature variance of the field. We show that the
entangled coherent states satisfy the sufficient condition for entanglement
based on quadrature variance measurement. We also show how robust our scheme is
against a low detection efficiency of homodyne detectors.Comment: 15 pages, 9 figures; extensively revised version; added Section
Investigation on 2007 abnormal wave occured at the West coast of Korea
Swell-type unexpected waves occurred along western coast of Korean at March, 2007 and it caused several deaths and heavy economic loss. Available field measurement data are collected to investigate this event, numerical model is setup to reproduce this unknown waves. We found several 1-min interval tidal elevation and sea level pressure (SLP) data along the western coast of Korea and analyzed it using wavelet technique. The wavelet power spectrum for sea water level anomalies is computed using the Morlet mother function. The high wave energy is occurred between 8 and 16 minutes during 0???2 KST 31 March 2007, and the sudden pressure jump of 3???5 hPa occurred simultaneously with high wave energy event. The numerical experiments of the abnormal wave were performed using 2-dimensional shallow water wave model (COMCOT), and air pressure forcing is made from the variation of SLP field and pressure jump from weather charts. We assume the air pressure jump of around 5 hPa is moving from Shandong of China to west coast of Korea. The sea water level by the travel of SLP field was changed all over west coast of Korea with low frequency and SLP field was not considered an original forcing of the abnormal wave. The sea level under the forcing of air pressure jump was obviously amplified by the Proudman resonant effect and it can reproduce the 2007 abnormal wave qualitatively
A theorem for the beam splitter entangler
It is conjectured that the an entanglement output states from a beam splitter
requires the nonclassicality in the input state(M.S. Kim, W. Son, V. Buzek and
P. L. Knight, Phys. Rev. A, 65, 032323(2002)). Here we give a proof for this
conjecture.Comment: Two relevant literatures added. To appear in Phys. Rev.
Gravitational Wave Spectrum in Inflation with Nonclassical States
The initial quantum state during inflation may evolve to a highly squeezed
quantum state due to the amplification of the time-dependent parameter,
, which may be the modified dispersion relation in
trans-Planckian physics. This squeezed quantum state is a nonclassical state
that has no counterpart in the classical theory. We have considered the
nonclassical states such as squeezed, squeezed coherent, and squeezed thermal
states, and calculated the power spectrum of the gravitational wave
perturbation when the mode leaves the horizon.Comment: 21 page
Comparisons of commercial frozen yogurt with ksu formulation
Ten samples of vanilla frozen yogurt were
purchased in Kansas and compared to a highprotein,
KSU formulation. The KSU
formulation had similar solids, fat, and sugar
contents as the commercial samples. All
commercial samples had lower protein (almost
less than half) content and more lactose, and
almost all samples had fewer lactic acid
bacteria than the KSU formulation. All but one
commercial sample had lower b-galactosidase
activity than the KSU formulation. This may
reflect the differing lactic acid bacterial
populations in the frozen yogurts
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