2,113 research outputs found
Quantum information processing using Josephson junctions coupled through cavities
Josephson junctions have been shown to be a promising solid-state system for
implementation of quantum computation. The significant two-qubit gates are
generally realized by the capacitive coupling between the nearest neighbour
qubits. We propose an effective Hamiltonian to describe charge qubits coupled
through the cavity. We find that nontrivial two-qubit gates may be achieved by
this coupling. The ability to interconvert localized charge qubits and flying
qubits in the proposed scheme implies that quantum network can be constructed
using this large scalable solid-state system.Comment: 5 pages, to appear in Phys Rev A; typos corrected, solutions in last
eqs. correcte
Universal quantum gates based on a pair of orthogonal cyclic states: Application to NMR systems
We propose an experimentally feasible scheme to achieve quantum computation
based on a pair of orthogonal cyclic states. In this scheme, quantum gates can
be implemented based on the total phase accumulated in cyclic evolutions. In
particular, geometric quantum computation may be achieved by eliminating the
dynamic phase accumulated in the whole evolution. Therefore, both dynamic and
geometric operations for quantum computation are workable in the present
theory. Physical implementation of this set of gates is designed for NMR
systems. Also interestingly, we show that a set of universal geometric quantum
gates in NMR systems may be realized in one cycle by simply choosing specific
parameters of the external rotating magnetic fields. In addition, we
demonstrate explicitly a multiloop method to remove the dynamic phase in
geometric quantum gates. Our results may provide useful information for the
experimental implementation of quantum logical gates.Comment: 9 pages, language revised, the publication versio
The Off-diagonal Goldberger-Treiman Relation and Its Discrepancy
We study the off-diagonal Goldberger-Treiman relation (ODGTR) and its
discrepancy (ODGTD) in the N, Delta, pi sector through O(p^2) using heavy
baryon chiral perturbation theory. To this order, the ODGTD and axial vector N
to Delta transition radius are determined solely by low energy constants. Loop
corrections appear at O(p^4). For low-energy constants of natural size, the
ODGTD would represent a ~ 2% correction to the ODGTR. We discuss the
implications of the ODGTR and ODGTD for lattice and quark model calculations of
the transition form factors and for parity-violating electroexcitation of the
Delta.Comment: 11 pages, 1 eps figur
A Two-stream Convolutional Network for Musculoskeletal and Neurological Disorders Prediction
Musculoskeletal and neurological disorders are the most common causes of walking problems among older people, and they often lead to diminished quality of life. Analyzing walking motion data manually requires trained professionals and the evaluations may not always be objective. To facilitate early diagnosis, recent deep learning-based methods have shown promising results for automated analysis, which can discover patterns that have not been found in traditional machine learning methods. We observe that existing work mostly applies deep learning on individual joint features such as the time series of joint positions. Due to the challenge of discovering inter-joint features such as the distance between feet (i.e. the stride width) from generally smaller-scale medical datasets, these methods usually perform sub-optimally. As a result, we propose a solution that explicitly takes both individual joint features and inter-joint features as input, relieving the system from the need of discovering more complicated features from small data. Due to the distinctive nature of the two types of features, we introduce a two-stream framework, with one stream learning from the time series of joint position and the other from the time series of relative joint displacement. We further develop a mid-layer fusion module to combine the discovered patterns in these two streams for diagnosis, which results in a complementary representation of the data for better prediction performance. We validate our system with a benchmark dataset of 3D skeleton motion that involves 45 patients with musculoskeletal and neurological disorders, and achieve a prediction accuracy of 95.56%, outperforming state-of-the-art methods
Recoil Order Chiral Corrections to Baryon Octet Axial Currents and Large QCD
We compute the chiral corrections to octet baryon axial currents through
in heavy baryon chiral perturbation theory, including both
octet and decuplet baryon intermediate states. We include the latter in a
consistent way by using the small scale expansion. We find that, in contrast to
the situation at , there exist no cancellations between octet
and decuplet contributions at . Consequently, the corrections spoil the expected scaling behavior of the chiral
expansion. We discuss this result in terms of the expansion. We also
consider the implications for determination of the strange quark contribution
to the nucleon spin from polarized deep inelastic scattering data.Comment: 7 page
Multilayers of Fluorinated Amphiphilic Polyions for Marine Fouling Prevention
Sequential layer-by-layer (LbL) deposition of polyelectrolytes followed by chemical cross-linking was investigated as a method to fabricate functional amphiphilic surfaces for marine biofouling prevention applications. A novel polyanion, grafted
with amphiphilic perfluoroalkyl polyethylene glycol (fPEG) side chains, was synthesized and subsequently used to introduce amphiphilic character to the LbL film. The structure of the polyanion was confirmed by FTIR and NMR. Amphiphilicity of the film assembly was demonstrated by both water and hexadecane static contact angles. XPS studies of the cross-linked and annealed amphiphilic LbL films revealed the increased concentration of fPEG content at the film interface. In antifouling assays, the amphiphilic LbL films effectively prevented the adhesion of the marine bacterium Pseudomonas (NCIMB 2021)
Future Directions in Parity Violation: From Quarks to the Cosmos
I discuss the prospects for future studies of parity-violating (PV)
interactions at low energies and the insights they might provide about open
questions in the Standard Model as well as physics that lies beyond it. I cover
four types of parity-violating observables: PV electron scattering; PV hadronic
interactions; PV correlations in weak decays; and searches for the permanent
electric dipole moments of quantum systems.Comment: Talk given at PAVI 06 workshop on parity-violating interactions,
Milos, Greece (May, 2006); 10 page
BES3 time of flight monitoring system
A Time of Flight monitoring system has been developed for BES3.
The light source is a 442-443 nm laser diode, which is stable and provides a
pulse width as narrow as 50 ps and a peak power as large as 2.6 W. Two
optical-fiber bundles with a total of 512 optical fibers, including spares, are
used to distribute the light pulses to the Time of Flight counters. The design,
operation, and performance of the system are described.Comment: 8 pages 16 figures, submitted to NI
Baryon Tri-local Interpolating Fields
We systematically investigate tri-local (non-local) three-quark baryon fields
with U_L(2)*U_R(2) chiral symmetry, according to their Lorentz and isospin
(flavor) group representations. We note that they can also be called as
"nucleon wave functions" due to this full non-locality. We study their chiral
transformation properties and find all the possible chiral multiplets
consisting J=1/2 and J=3/2 baryon fields. We find that the axial coupling
constant |g_A| = 5/3 is only for nucleon fields belonging to the chiral
representation (1/2,1)+(1,1/2) which contains both nucleon fields and Delta
fields. Moreover, all the nucleon fields belonging to this representation have
|g_A| = 5/3.Comment: 8 pages, 3 tables, accepted by EPJ
Generation of continuous variable squeezing and entanglement of trapped ions in time-varying potentials
We investigate the generation of squeezing and entanglement for the motional
degrees of freedom of ions in linear traps, confined by time-varying and
oscillating potentials, comprised of an DC and an AC component. We show that
high degrees of squeezing and entanglement can be obtained by controlling
either the DC or the AC trapping component (or both), and by exploiting
transient dynamics in regions where the ions' motion is unstable, without any
added optical control. Furthermore, we investigate the time-scales over which
the potentials should be switched in order for the manipulations to be most
effective.Comment: 10 pages, submitted to Quantum Information Processing (special issue
on Quantum Decoherence and Entanglement
- …