269,139 research outputs found
Observation of quantum interference as a function of Berry's phase in a complex Hadamard optical network
Emerging models of quantum computation driven by multi-photon quantum
interference, while not universal, may offer an exponential advantage over
classical computers for certain problems. Implementing these circuits via
geometric phase gates could mitigate requirements for error correction to
achieve fault tolerance while retaining their relative physical simplicity. We
report an experiment in which a geometric phase is embedded in an optical
network with no closed-loops, enabling quantum interference between two photons
as a function of the phase.Comment: Comments welcom
Analysis and identification of possible automation approaches for embedded systems design flows
Sophisticated and high performance embedded systems are present in an increasing number of application domains. In this context, formal-based design methods have been studied to make the development process robust and scalable. Models of computation (MoC) allows the modeling of an application at a high abstraction level by using a formal base. This enables analysis before the application moves to the implementation phase. Different tools and frameworks supporting MoCs have been developed. Some of them can simulate the models and also verify their functionality and feasibility before the next design steps. In view of this, we present a novel method for analysis and identification of possible automation approaches applicable to embedded systems design flow supported by formal models of computation. A comprehensive case study shows the potential and applicability of our method11212
Semi-Markov approach to continuous time random walk limit processes
Continuous time random walks (CTRWs) are versatile models for anomalous
diffusion processes that have found widespread application in the quantitative
sciences. Their scaling limits are typically non-Markovian, and the computation
of their finite-dimensional distributions is an important open problem. This
paper develops a general semi-Markov theory for CTRW limit processes in
with infinitely many particle jumps (renewals) in finite time
intervals. The particle jumps and waiting times can be coupled and vary with
space and time. By augmenting the state space to include the scaling limits of
renewal times, a CTRW limit process can be embedded in a Markov process.
Explicit analytic expressions for the transition kernels of these Markov
processes are then derived, which allow the computation of all finite
dimensional distributions for CTRW limits. Two examples illustrate the proposed
method.Comment: Published in at http://dx.doi.org/10.1214/13-AOP905 the Annals of
Probability (http://www.imstat.org/aop/) by the Institute of Mathematical
Statistics (http://www.imstat.org
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