5,213 research outputs found
Large-Scale Schr\"odinger-Cat States and Majorana Bound States in Coupled Circuit-QED Systems
We have studied the low-lying excitations of a chain of coupled circuit-QED
systems, and report several intriguing properties of its two nearly degenerate
ground states. The ground states are Schr\"odinger cat states at a truly large
scale, involving maximal entanglement between the resonator and the qubit, and
are mathematically equivalent to Majorana bound states. With a suitable design
of physical qubits, they are protected against local fluctuations and
constitute a non-local qubit. Further, they can be probed and manipulated
coherently by attaching an empty resonator to one end of the circuit-QED chain.Comment: 5 pages; 2 figures; incorrect references corrected; typos correcte
Non-Relativistic Superstring Theories
We construct a supersymmetric version of the ``critical'' non-relativistic
bosonic string theory\cite{Kim:2007hb} with its manifest global symmetry. We
introduce the anticommuting CFT which is the super partner of the
CFT. The conformal weights of the and fields are both
1/2. The action of the fermionic sector can be transformed into that of the
relativistic superstring theory. We explicitly quantize the theory with
manifest SO(8) symmetry and find that the spectrum is similar to that of Type
IIB superstring theory. There is one notable difference: the fermions are
non-chiral. We further consider ``noncritical'' generalizations of the
supersymmetric theory using the superspace formulation. There is an infinite
range of possible string theories similar to the supercritical string theories.
We comment on the connection between the critical non-relativistic string
theory and the lightlike Linear Dilaton theory.Comment: Typos corrected, references added. A version to appear in Phys. Rev.
QED corrections to isospin-related decay rates of charged and neutral B mesons
We estimate the isospin-violating QED radiative corrections to the
charged-to-neutral ratios of the decay rates for B^+ and B^0 in non-leptonic B
meson decays. In particular, these corrections are potentially important for
precision measurement of the charged-to-neutral production ratio of B meson in
e^+e^- annihilation. We calculate explicitly the QED corrections to the ratios
of two different types of decay rates \Gamma(B^+ \to J/\psi K^+)/\Gamma(B^0 \to
J/\psi K^0) and \Gamma(B^+ \to D^+_S \bar{D^0})/\Gamma(B^0 \to D^+_S D^-)
taking into account the form factors of the mesons based on the vector meson
dominance model, and compare them with the results obtained for the point-like
mesons.Comment: 7 pages, 9 eps figure
Shot Noise and Full Counting Statistics from Non-equilibrium Plasmons in Luttinger-Liquid Junctions
We consider a quantum wire double junction system with each wire segment
described by a spinless Luttinger model, and study theoretically shot noise in
this system in the sequential tunneling regime. We find that the
non-equilibrium plasmonic excitations in the central wire segment give rise to
qualitatively different behavior compared to the case with equilibrium
plasmons. In particular, shot noise is greatly enhanced by them, and exceeds
the Poisson limit. We show that the enhancement can be explained by the
emergence of several current-carrying processes, and that the effect disappears
if the channels effectively collapse to one due to, {\em e.g.}, fast plasmon
relaxation processes.Comment: 9 pages; IOP Journal style; several changes in the tex
Decoherence Driven Quantum Transport
We propose a new mechanism to generate a dc current of particles at zero bias
based on a noble interplay between coherence and decoherence. We show that a dc
current arises if the transport process in one direction is maintained coherent
while the process in the opposite direction is incoherent. We provide possible
implementations of the idea using an atomic Michelson and an atomic
Aharonov-Bohm interferometer.Comment: 4 pages, 3 figure
Cosmic holographic bounds with UV and IR cutoffs
We introduce the cosmic holographic bounds with two UV and IR cutoff scales,
to deal with both the inflationary universe in the past and dark energy in the
future. To describe quantum fluctuations of inflation on sub-horizon scales, we
use the Bekenstein-Hawking energy bound. However, it is not justified that the
D-bound is satisfied with the coarse-grained entropy. The Hubble bounds are
introduced for classical fluctuations of inflation on super-horizon scales. It
turns out that the Hubble entropy bound is satisfied with the entanglement
entropy and the Hubble temperature bound leads to a condition for the slow-roll
inflation. In order to describe the dark energy, we introduce the holographic
energy density which is the one saturating the Bekenstein-Hawking energy bound
for a weakly gravitating system. Here the UV (IR) cutoff is given by the Planck
scale (future event horizon), respectively. As a result, we find the close
connection between quantum and classical fluctuations of inflation, and dark
energy.Comment: 15page
The Globular Cluster System of M60 (NGC 4649). I. CFHT MOS Spectroscopy and Database
We present the measurement of radial velocities for globular clusters in M60,
giant elliptical galaxy in the Virgo cluster. Target globular cluster
candidates were selected using the Washington photometry based on the deep
16\arcmin \times 16\arcmin images taken at the KPNO 4m and using the
photometry derived from the HST/WFPC2 archive images. The spectra of the target
objects were obtained using the Multi-Object Spectrograph (MOS) at the
Canada-France-Hawaii Telescope (CFHT). We have measured the radial velocity for
111 objects in the field of M60: 93 globular clusters (72 blue globular
clusters with and 21 red globular clusters with
), 11 foreground stars, 6 small galaxies, and the nucleus of
M60. The measured velocities of the 93 globular clusters range from
km s to km s, with a mean value of
km s, which is in good agreement with the velocity of the nucleus of M60
( km s). Combining our results with data in the
literature, we present a master catalog of radial velocities for 121 globular
clusters in M60. The velocity dispersion of the globular clusters in the master
catalog is found to be km s for the entire sample,
km s for 83 blue globular clusters, and
km s for 38 red globular clusters.Comment: 29 pages, 8 figures. To appear in Ap
A New Microsensor System for Plant Root Zone Monitoring
The objective of this work is to develop a new microsensor system that can monitor dissolved oxygen and hydration environment at the plant root zone. A miniaturized plant growth system is prepared including the root zone layer, either a porous ceramic tube or porous ceramic wafer on which the plant is grown, and an underlying fluidic channel to deliver nutrients and water to the root zone. We demonstrate the feasibility of using a flexible microsensor array for dissolved oxygen detection, and a four-electrode impedance microelectrode for wetness detection on the surface of a porous tube nutrient delivery system. The unique features of the microsensor array and microelectrodes include small size, simple structure, mechanical flexibility and multipoint sensing. The new plant root microsystem technology is anticipated being a novel tool for plant root physiology
Basis States for Relativistic, Dynamically-Entangled Particles
In several recent papers on entanglement in relativistic quantum systems and
relativistic Bell's inequalities, relativistic Bell-type two-particle states
have been constructed in analogy to non-relativistic states. These
constructions do not have the form suggested by relativistic invariance of the
dynamics. Two relativistic formulations of Bell-type states are shown for
massive particles, one using the standard Wigner spin basis and one using the
helicity basis. The construction hinges on the use of Clebsch-Gordan
coefficients of the Poincar\'e group to reduce the direct product of two
unitary irreducible representations (UIRs) into a direct sum of UIRs.Comment: 19 pages, three tables, revte
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