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Dissipation Effects in Hybrid Systems
The dissipation effect in a hybrid system is studied in this Letter. The
hybrid system is a compound of a classical magnetic particle and a quantum
single spin. Two cases are considered. In the first case, we investigate the
effect of the dissipative quantum subsystem on the motion of its classical
partner. Whereas in the second case we show how the dynamics of the quantum
single spin are affected by the dissipation of the classical particle.
Extension to general dissipative hybrid systems is discussed.Comment: 4+ pages, 4 figure
A model for retention on short, intermediate and long time-scale in ferroelectric thin films
We developed a model with no adjustable parameter for retention loss at short
and long time scale in ferroelectric thin-film capacitors. We found that the
predictions of this model are in good agreement with the experimental
observations in the literature. In particular, it explains why a power-law
function shows better fitting than a linear-log relation on a short time scale
(10^-7 s to 1 s) and why a stretched exponential relation gives more precise
description than a linear-log plot on a long time scale (>100 s), as reported
by many researchers in the past. More severe retention losses at higher
temperatures and in thinner films have also been correctly predicted by the
present theory.Comment: 15 pages and 3 figure
(1 + p)-Dimensional Open D(p - 2) Brane Theories
The dynamics of a Dp brane can be described either by an open string ending
on this brane or by an open D(p - 2) brane ending on the same Dp brane. The
ends of the open string couple to a Dp brane worldvolume gauge field while the
boundary of the open D(p - 2) brane couples to a (p - 2)-form worldvolume
potential whose field strength is Poincare dual to that of the gauge field on
the Dp-brane worldvolume. With this in mind, we find that the Poincare dual of
the fixed rank-2 magnetic field used in defining a (1 + p)-dimensional
noncommutative Yang-Mills (NCYM) gives precisely a near-critical electric field
for the open D(p - 2) brane. We therefore find (1 + p)-dimensional open D(p -
2) brane theories along the same line as for obtaining noncommutative open
string theories (NCOS), OM theory and open Dp brane theories (ODp) from NS5
brane. Similarly, the Poincare dual of the near-critical electric field used in
defining a (1 + p)-dimensional NCOS gives a fixed magnetic-like field. This
field along with the same bulk field scalings defines a (1 + p)-dimensional
noncommutative field theory. In the same spirit, we can have various (1 +
5)-dimensional noncommutative field theories resulting from the existence of
ODp if the description of open D(4 - p) brane ending on the NS5 brane is
insisted.Comment: 35 pages, references added and discussion on decoupled field theories
refine
The Carriers of the Interstellar Unidentified Infrared Emission Features: Constraints from the Interstellar C-H Stretching Features at 3.2-3.5 Micrometers
The unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and
11.3 micrometer, commonly attributed to polycyclic aromatic hydrocarbon (PAH)
molecules, have been recently ascribed to mixed aromatic/aliphatic organic
nanoparticles. More recently, an upper limit of <9% on the aliphatic fraction
(i.e., the fraction of carbon atoms in aliphatic form) of the UIE carriers
based on the observed intensities of the 3.4 and 3.3 micrometer emission
features by attributing them to aliphatic and aromatic C-H stretching modes,
respectively, and assuming A_34./A_3.3~0.68 derived from a small set of
aliphatic and aromatic compounds, where A_3.4 and A_3.3 are respectively the
band strengths of the 3.4 micrometer aliphatic and 3.3 micrometer aromatic C-H
bonds.
To improve the estimate of the aliphatic fraction of the UIE carriers, here
we analyze 35 UIE sources which exhibit both the 3.3 and 3.4 micrometer C-H
features and determine I_3.4/I_3.3, the ratio of the power emitted from the 3.4
micrometer feature to that from the 3.3 micrometer feature. We derive the
median ratio to be ~ 0.12. We employ density functional theory
and second-order perturbation theory to compute A_3.4/A_3.3 for a range of
methyl-substituted PAHs. The resulting A_3.4/A_3.3 ratio well exceeds 1.4, with
an average ratio of ~1.76. By attributing the 3.4 micrometer
feature exclusively to aliphatic C-H stretch (i.e., neglecting anharmonicity
and superhydrogenation), we derive the fraction of C atoms in aliphatic form to
be ~2%. We therefore conclude that the UIE emitters are predominantly aromatic.Comment: 14 pages, 5 figures, 1 table; accepted for publication in The
Astrophysical Journa
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