8,117 research outputs found
A room temperature indirect formic acid fuel cell
Session B-1.2: Vehicle, Gas Processing/Storage, Direct-Fuel FCspublished_or_final_versionThe 218th Meeting of the Electrochemical Society (ECS Meeting 2010), Las Vegas, NV., 10-15 October 2010. In Electrochemical Society Meeting Abstracts, 2010, abstract 67
Non-Markovian Quantum Trajectories of Many-Body Quantum Open Systems
A long-standing open problem in non-Markovian quantum state diffusion (QSD)
approach to open quantum systems is to establish the non-Markovian QSD
equations for multiple qubit systems. In this paper, we settle this important
question by explicitly constructing a set of exact time-local QSD equations for
-qubit systems. Our exact time-local (convolutionless) QSD equations have
paved the way towards simulating quantum dynamics of many-body open systems
interacting with a common bosonic environment. The applicability of this
multiple-qubit stochastic equation is exemplified by numerically solving
several quantum open many-body systems concerning quantum coherence dynamics
and dynamical control.Comment: 8 pages, 2 figures. manuscript revised and reference update
Taking Stock: A report from the UK Teacher Education Network for sustainable development (ESD) /global citizenship (GC) - survey on provision for ESD/GC in initial teacher education in the UK
In 2009-10, the UK Teacher Education (TE) Network for Education for Sustainable Development and Global Citizenship (ESDGC) developed and implemented anemail survey to explore how teacher educators approach ESDGC in their courseprovision. The survey aimed to establish the pattern of Teacher Educationprovision for sustainable development/global citizenship across the UK in primaryand secondary so as to work with colleagues to support and develop provision in amore consistent form. It was sent to all Heads of Education in all English highereducation providers and to named contacts in Scotland, Northern Ireland andWales. It was also sent to all School - Centred Initial Teacher Training (SCITTs).By June 2010, 32 responses had been received from 27 providers. Researchers atthe Development Education Research Centre (DERC) were commissioned to workwith the Network Management Team at the Centre for Cross Curricular Initiatives(CCCI) to analyse the data and produce this report
Non-Markovian Fermionic Stochastic Schr\"{o}dinger Equation for Open System Dynamics
In this paper we present an exact Grassmann stochastic Schr\"{o}dinger
equation for the dynamics of an open fermionic quantum system coupled to a
reservoir consisting of a finite or infinite number of fermions. We use this
stochastic approach to derive the exact master equation for a fermionic system
strongly coupled to electronic reservoirs. The generality and applicability of
this Grassmann stochastic approach is justified and exemplified by several
quantum open system problems concerning quantum decoherence and quantum
transport for both vacuum and finite-temperature fermionic reservoirs. We show
that the quantum coherence property of the quantum dot system can be profoundly
modified by the environment memory.Comment: 10.5 pages, 3 figure
Separating Stimulus-Induced and Background Components of Dynamic Functional Connectivity in Naturalistic fMRI
We consider the challenges in extracting stimulus-related neural dynamics from other intrinsic processes and noise in naturalistic functional magnetic resonance imaging (fMRI). Most studies rely on inter-subject correlations (ISC) of low-level regional activity and neglect varying responses in individuals. We propose a novel, data-driven approach based on low-rank plus sparse (L+S) decomposition to isolate stimulus-driven dynamic changes in brain functional connectivity (FC) from the background noise, by exploiting shared network structure among subjects receiving the same naturalistic stimuli. The time-resolved multi-subject FC matrices are modeled as a sum of a low-rank component of correlated FC patterns across subjects, and a sparse component of subject-specific, idiosyncratic background activities. To recover the shared low-rank subspace, we introduce a fused version of principal component pursuit (PCP) by adding a fusion-type penalty on the differences between the columns of the low-rank matrix. The method improves the detection of stimulus-induced group-level homogeneity in the FC profile while capturing inter-subject variability. We develop an efficient algorithm via a linearized alternating direction method of multipliers to solve the fused-PCP. Simulations show accurate recovery by the fused-PCP even when a large fraction of FC edges are severely corrupted. When applied to natural fMRI data, our method reveals FC changes that were time-locked to auditory processing during movie watching, with dynamic engagement of sensorimotor systems for speech-in-noise. It also provides a better mapping to auditory content in the movie than ISC
Simulation studies of a phenomenological model for elongated virus capsid formation
We study a phenomenological model in which the simulated packing of hard,
attractive spheres on a prolate spheroid surface with convexity constraints
produces structures identical to those of prolate virus capsid structures. Our
simulation approach combines the traditional Monte Carlo method with a modified
method of random sampling on an ellipsoidal surface and a convex hull searching
algorithm. Using this approach we identify the minimum physical requirements
for non-icosahedral, elongated virus capsids, such as two aberrant flock house
virus (FHV) particles and the prolate prohead of bacteriophage , and
discuss the implication of our simulation results in the context of recent
experimental findings. Our predicted structures may also be experimentally
realized by evaporation-driven assembly of colloidal spheres
Quantum secret sharing between m-party and n-party with six states
We propose a quantum secret sharing scheme between -party and -party
using three conjugate bases, i.e. six states. A sequence of single photons,
each of which is prepared in one of the six states, is used directly to encode
classical information in the quantum secret sharing process. In this scheme,
each of all members in group 1 choose randomly their own secret key
individually and independently, and then directly encode their respective
secret information on the states of single photons via unitary operations, then
the last one (the th member of group 1) sends of the resulting qubits
to each of group 2. By measuring their respective qubits, all members in group
2 share the secret information shared by all members in group 1. The secret
message shared by group 1 and group 2 in such a way that neither subset of each
group nor the union of a subset of group 1 and a subset of group 2 can extract
the secret message, but each whole group (all the members of each group) can.
The scheme is asymptotically 100% in efficiency. It makes the Trojan horse
attack with a multi-photon signal, the fake-signal attack with EPR pairs, the
attack with single photons, and the attack with invisible photons to be
nullification. We show that it is secure and has an advantage over the one
based on two conjugate bases. We also give the upper bounds of the average
success probabilities for dishonest agent eavesdropping encryption using the
fake-signal attack with any two-particle entangled states. This protocol is
feasible with present-day technique.Comment: 7 page
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