27,049 research outputs found
Continuous-Time Random Walks at All Times
Continuous-time random walks (CTRW) play important role in understanding of a
wide range of phenomena. However, most theoretical studies of these models
concentrate only on stationary-state dynamics. We present a new theoretical
approach, based on generalized master equations picture, that allowed us to
obtain explicit expressions for Laplace transforms for all dynamic quantities
for different CTRW models. This theoretical method leads to the effective
description of CTRW at all times. Specific calculations are performed for
homogeneous, periodic models and for CTRW with irreversible detachments. The
approach to stationary states for CTRW is analyzed. Our results are also used
to analyze generalized fluctuations theorem
Spatial Resonator Solitons
Spatial solitons can exist in various kinds of nonlinear optical resonators
with and without amplification. In the past years different types of these
localized structures such as vortices, bright, dark solitons and phase solitons
have been experimentally shown to exist. Many links appear to exist to fields
different from optics, such as fluids, phase transitions or particle physics.
These spatial resonator solitons are bistable and due to their mobility suggest
schemes of information processing not possible with the fixed bistable elements
forming the basic ingredient of traditional electronic processing. The recent
demonstration of existence and manipulation of spatial solitons in emiconductor
microresonators represents a step in the direction of such optical parallel
processing applications. We review pattern formation and solitons in a general
context, show some proof of principle soliton experiments on slow systems, and
describe in more detail the experiments on semiconductor resonator solitons
which are aimed at applications.Comment: 15 pages, 32 figure
Convergence of the state of a passive nonlinear plant with an L2 input
In this paper, we consider a strictly output passive nonlinear plant P with storage function H. We assume that P is zero-state detectable. Under some mild conditions on H, we show that the state x of the plant converges to zero for any L2 input. This implies the solvability for all t ≥ 0 of the system equations, for every input in L^2_{loc} We define a stability notion called L2 system-stable, a variant to the L2-stability concept, which has a nice interconnection properties
Strong coupling of a qubit to shot noise
We perform a nonperturbative analysis of a charge qubit in a double quantum
dot structure coupled to its detector. We show that strong detector-dot
interaction tends to slow down and halt coherent oscillations. The transitions
to a classical and a low-temperature quantum overdamping (Zeno) regime are
studied. In the latter, the physics of the dissipative phase transition
competes with the effective shot noise.Comment: 5 pages, 4 figure
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