3,648 research outputs found
Crossover in Growth Law and Violation of Superuniversality in the Random Field Ising Model
We study the nonconserved phase ordering dynamics of the d = 2, 3 random
field Ising model, quenched to below the critical temperature. Motivated by the
puzzling results of previous work in two and three di- mensions, reporting a
crossover from power-law to logarithmic growth, together with superuniversal
behavior of the correlation function, we have undertaken a careful
investigation of both the domain growth law and the autocorrelation function.
Our main results are as follows: We confirm the crossover to asymptotic
logarithmic behavior in the growth law, but, at variance with previous
findings, the exponent in the preasymptotic power law is disorder-dependent,
rather than being the one of the pure system. Furthermore, we find that the
autocorre- lation function does not display superuniversal behavior. This
restores consistency with previous results for the d = 1 system, and fits
nicely into the unifying scaling scheme we have recently proposed in the study
of the random bond Ising model.Comment: To be published in Physical Review
Amplification of Fluctuations in Unstable Systems with Disorder
We study the early-stage kinetics of thermodynamically unstable systems with
quenched disorder. We show analytically that the growth of initial fluctuations
is amplified by the presence of disorder. This is confirmed by numerical
simulations of morphological phase separation (MPS) in thin liquid films and
spinodal decomposition (SD) in binary mixtures. We also discuss the
experimental implications of our results.Comment: 15 pages, 4 figure
Role of Octreotide in Pediatric Gastrointestinal Bleeding Secondary to Angiodysplasia in Children With Right Heart Failure
Objectives: Angiodysplasia (AD) is a relatively uncommon cause of gastrointestinal bleeding in children and may be seen in right heart failure. Octreotide has been used successfully in adult patients with gastrointestinal bleeding due to ADs.
Methods: We describe 2 patients who had congenital heart disease with right heart failure and gastrointestinal bleeding from AD.
Results: AD lesions were documented on traditional endoscopy and capsule endoscopy. Bleeding resolved after initiation of IV octreotide and did not recur on subcutaneous octreotide during the 2-year follow-up period.
Conclusions: Based on the successful outcomes in the 2 patients, a trial of octreotide may be considered in pediatric patients who present with gastrointestinal bleeding secondary to AD
Driving-dependent damping of Rabi oscillations in two-level semiconductor systems
We propose a mechanism to explain the nature of the damping of Rabi
oscillations with increasing driving-pulse area in localized semiconductor
systems, and have suggested a general approach which describes a coherently
driven two-level system interacting with a dephasing reservoir. Present
calculations show that the non-Markovian character of the reservoir leads to
the dependence of the dephasing rate on the driving-field intensity, as
observed experimentally. Moreover, we have shown that the damping of Rabi
oscillations might occur as a result of different dephasing mechanisms for both
stationary and non-stationary effects due to coupling to the environment.
Present calculated results are found in quite good agreement with available
experimental measurements
Controlling Entanglement Generation in External Quantum Fields
Two, non-interacting two-level atoms immersed in a common bath can become
mutually entangled when evolving with a Markovian, completely positive
dynamics. For an environment made of external quantum fields, this phenomenon
can be studied in detail: one finds that entanglement production can be
controlled by varying the bath temperature and the distance between the atoms.
Remarkably, in certain circumstances, the quantum correlations can persist in
the asymptotic long-time regime.Comment: 12 pages, to appear in J. Opt. B: Quantum Semiclass. Op
Pengaruh Quality of Work Life Dan Motivasi Intrinsik Terhadap Kinerja Perawat RSUD A.m. Parikesit Tenggarong Seberang
The purpose of this study was to determine the influence of Quality of Work Life and Motivation Intrinsic on Employee Performance. This research was conducted at the Hospital A.M. Parikesit Tenggarong Seberang. The sample of this study consists of 62 respondent. Sampling method using simple random sampling. The data in this study using primary data, interviews and questionnaires. Hypothesis test used in this study is Multiple Linear Regression using SPSS for Windows Version 21. The results of this study show that: 1) Quality of work life has a positive and significant effect on employee performance at the Hospital A.M. Parikesit Tenggarong Seberang, 2) Motivation intrinsic has a positive and significant effect on employee performance at the Hospital A.M. Parikesit Tenggarong Seberang
Theory versus experiment for vacuum Rabi oscillations in lossy cavities
The 1996 Brune {\it et al.} experiment on vacuum Rabi oscillation is analyzed
by means of alternative models of atom-reservoir interaction. Agreement with
experimental Rabi oscillation data can be obtained if one defines jump
operators in the dressed-state basis, and takes into account thermal
fluctuations between dressed states belonging to the same manifold. Such
low-frequency transitions could be ignored in a closed cavity, but the cavity
employed in the experiment was open, which justifies our assumption. The cavity
quality factor corresponding to the data is , whereas
reported in the experiment was . The rate of decoherence arising
from opening of the cavity can be of the same order as an analogous correction
coming from finite time resolution (formally equivalent to
collisional decoherence). Peres-Horodecki separability criterion shows that the
rate at which the atom-field state approaches a separable state is controlled
by fluctuations between dressed states from the same manifold, and not by the
rate of transitions towards the ground state. In consequence, improving the
factor we do not improve the coherence properties of the cavity.Comment: typo in eq. (60) corrected; (older comments: 14 figures (1 added),
value of Q improved, a section on the Peres-Horodecki test of separability
added, various small improvements; v3 includes discussion of finite time
resolution, v4 includes microscopic derivation of the master equation
Optimal Reachability in Divergent Weighted Timed Games
Weighted timed games are played by two players on a timed automaton equipped
with weights: one player wants to minimise the accumulated weight while
reaching a target, while the other has an opposite objective. Used in a
reactive synthesis perspective, this quantitative extension of timed games
allows one to measure the quality of controllers. Weighted timed games are
notoriously difficult and quickly undecidable, even when restricted to
non-negative weights. Decidability results exist for subclasses of one-clock
games, and for a subclass with non-negative weights defined by a semantical
restriction on the weights of cycles. In this work, we introduce the class of
divergent weighted timed games as a generalisation of this semantical
restriction to arbitrary weights. We show how to compute their optimal value,
yielding the first decidable class of weighted timed games with negative
weights and an arbitrary number of clocks. In addition, we prove that
divergence can be decided in polynomial space. Last, we prove that for untimed
games, this restriction yields a class of games for which the value can be
computed in polynomial time
Applications of the group SU(1,1) for quantum computation and tomography
This paper collects miscellaneous results about the group SU(1,1) that are
helpful in applications in quantum optics. Moreover, we derive two new results,
the first is about the approximability of SU(1,1) elements by a finite set of
elementary gates, and the second is about the regularization of group
identities for tomographic purposes.Comment: 11 pages, no figure
A comparative study of model ingredients: fragmentation in heavy-ion collisions using quantum molecular dynamics model
We aim to understand the role of NN cross-sections, equation of state as well
as different model ingredients such as width of Gaussian, clusterisation range
and different clusterisation algorithms in multifragmentation using quantum
molecular dynamics model. We notice that all model ingredients have sizable
effect on the fragment pattern.Comment: 12 Pages, 4 Figure
- …