1,729 research outputs found
Universal first-passage statistics of aging processes
Many out of equilibrium phenomena, such as diffusion-limited reactions or
target search processes, are controlled by first-passage events. So far the
general determination of the mean first-passage time (FPT) to a target in
confinement has left aside aging processes, involved in contexts as varied as
glassy dynamics, tracer diffusion in biological membranes or transport of cold
atoms in optical lattices. Here we consider general non-Markovian
scale-invariant processes in arbitrary dimension, displaying aging, and
demonstrate that all the moments of the FPT obey universal scalings with the
confining volume with non trivial exponents. Our analysis shows that a
nonlinear scaling of the mean FPT with the volume is the hallmark of aging and
provides a general tool to quantify its impact on first-passage kinetics in
confinement
Quantum state engineering in a cavity by Stark chirped rapid adiabatic passage
We propose a robust scheme to generate single-photon Fock states and
atom-photon and atom-atom entanglement in atom-cavity systems. We also present
a scheme for quantum networking between two cavity nodes using an atomic
channel. The mechanism is based on Stark-chirped rapid adiabatic passage
(SCRAP) and half-SCRAP processes in a microwave cavity. The engineering of
these states depends on the design of the adiabatic dynamics through the static
and dynamic Stark shifts.Comment: 7 pages, 8 figures, to be appeared in PL
Fast SWAP gate by adiabatic passage
We present a process for the construction of a SWAP gate which does not
require a composition of elementary gates from a universal set. We propose to
employ direct techniques adapted to the preparation of this specific gate. The
mechanism, based on adiabatic passage, constitutes a decoherence-free method in
the sense that spontaneous emission and cavity damping are avoided.Comment: 5 pages, 4 figures, submitted to Phys. Re
Adiabatic creation of entangled states by a bichromatic field designed from the topology of the dressed eigenenergies
Preparation of entangled pairs of coupled two-state systems driven by a
bichromatic external field is studied. We use a system of two coupled spin-1/2
that can be translated into a three-state ladder model whose intermediate state
represents the entangled state. We show that this entangled state can be
prepared in a robust way with appropriate fields. Their frequencies and
envelopes are derived from the topological properties of the model.Comment: 10 pages, 9 figure
On the topology of adiabatic passage
We examine the topology of eigenenergy surfaces characterizing the population
transfer processes based on adiabatic passage. We show that this topology is
the essential feature for the analysis of the population transfers and the
prediction of its final result. We reinterpret diverse known processes, such as
stimulated Raman adiabatic passage (STIRAP), frequency-chirped adiabatic
passage and Stark-chirped rapid adiabatic passage (SCRAP). Moreover, using this
picture, we display new related possibilities of transfer. In particular, we
show that we can selectively control the level which will be populated in
STIRAP process in Lambda or V systems by the choice of the peak amplitudes or
the pulse sequence
Adiabatic tracking for photo- and magneto-association of Bose-Einstein condensates with Kerr nonlinearities
We develop the method of adiabatic tracking for photo- and
magneto-association of Bose-Einstein atomic condensates with models that
include Kerr type nonlinearities. We show that the inclusion of these terms can
produce qualitatively important modifications in the adiabatic dynamics, like
the appearance of bifurcations, in which the trajectory that is being tracked
loses its stability. As a consequence the adiabatic theorem does not apply and
the adiabatic transfer can be strongly degraded. This degradation can be
compensated by using fields that are strong enough compared with the values of
the Kerr terms. The main result is that, despite these potentially detrimental
features, there is always a choice of the detuning that leads to an efficient
adiabatic tracking, even for relatively weak fields
Bayesian method approach for fatigue life distribution estimation of rubber components
The constantly increasing market requirements of high-quality vehicles compel automotive manufacturers to perform lifetime testing to verify the reliability levels of new products. A common problem is that only a small number of samples of a system\u27s component can be tested. In automotive applications, mechanical components subjected to cyclic loading have to be designed against fatigue. In this paper, the Bayesian estimation of lognormal distribution parameters (usually used to define the fatigue lifetime of rubber components) is studied to improve the accuracy of estimation while incorporating the available knowledge on the product. In particular, the finite element results and experts\u27 opinions are considered prior knowledge. For lifetime prediction by Finite Element Method (FEM), a model based on the Brown-Miller law was developed for the rubberlike boot seal material
- …