56 research outputs found
Non-Markovian dynamics of a microcavity coupled to a waveguide in photonic crystals
In this paper, the non-Markovian dynamics of a microcavity coupled to a
waveguide in photonic crystals is studied based on Fano-type tight binding
model. Using the exact master equation, we solve analytically and numerically
the temporal evolution of the cavity coherent state and the associated physical
observables. A critical transition is revealed when the coupling increase
between the cavity and the waveguide. In particular, the cavity field becomes
dissipationless when the coupling strength goes beyond a critical value, as a
manifestation of strong non-Markovian memory effect. The result also indicates
that the cavity can maintain in a coherent state with arbitrary small number of
photons when it strongly couples to the waveguide at very low temperature.
These properties can be measured experimentally through the photon current
flowing over the waveguide in photonic crystals.Comment: 7 pages, 5 figure
Long-time Low-latency Quantum Memory by Dynamical Decoupling
Quantum memory is a central component for quantum information processing
devices, and will be required to provide high-fidelity storage of arbitrary
states, long storage times and small access latencies. Despite growing interest
in applying physical-layer error-suppression strategies to boost fidelities, it
has not previously been possible to meet such competing demands with a single
approach. Here we use an experimentally validated theoretical framework to
identify periodic repetition of a high-order dynamical decoupling sequence as a
systematic strategy to meet these challenges. We provide analytic
bounds-validated by numerical calculations-on the characteristics of the
relevant control sequences and show that a "stroboscopic saturation" of
coherence, or coherence plateau, can be engineered, even in the presence of
experimental imperfection. This permits high-fidelity storage for times that
can be exceptionally long, meaning that our device-independent results should
prove instrumental in producing practically useful quantum technologies.Comment: abstract and authors list fixe
f(R) theories
Over the past decade, f(R) theories have been extensively studied as one of
the simplest modifications to General Relativity. In this article we review
various applications of f(R) theories to cosmology and gravity - such as
inflation, dark energy, local gravity constraints, cosmological perturbations,
and spherically symmetric solutions in weak and strong gravitational
backgrounds. We present a number of ways to distinguish those theories from
General Relativity observationally and experimentally. We also discuss the
extension to other modified gravity theories such as Brans-Dicke theory and
Gauss-Bonnet gravity, and address models that can satisfy both cosmological and
local gravity constraints.Comment: 156 pages, 14 figures, Invited review article in Living Reviews in
Relativity, Published version, Comments are welcom
O transtorno da compulsão alimentar (TCA) tem impacto no reganho de peso após a cirurgia bariátrica? Relato de caso
Co-simulation of cyber-physical systems using a DEVS wrapping strategy in the MECSYCO middleware
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