13,354 research outputs found
Contextual classification of multispectral image data
There are no author-identified significant results in this report
Optimal squeezing, pure states, and amplification of squeezing in resonance fluorescence
It is shown that 100% squeezed output can be produced in the resonance
fluorescence from a coherently driven two-level atom interacting with a
squeezed vacuum. This is only possible for squeezed input, and is
associated with a pure atomic state, i.e., a completely polarized state. The
quadrature for which optimal squeezing occurs depends on the squeezing phase
the Rabi frequency and the atomic detuning . Pure
states are described for arbitrary not just or as in
previous work. For small values of there may be a greater degree of
squeezing in the output field than the input - i.e., we have squeezing
amplification.Comment: 6 pages & 7 figures, Submitted to Phys. Rev.
Remote terminal system evaluation
An Earth Resources Data Processing System was developed to evaluate the system for training, technology transfer, and data processing. In addition to the five sites included in this project two other sites were connected to the system under separate agreements. The experience of these two sites is discussed. The results of the remote terminal project are documented in seven reports: one from each of the five project sites, Purdue University, and an overview report summarizing the other six reports
Solutions to the Jaynes-Cummings model without the rotating-wave approximation
By using extended bosonic coherent states, the solution to the
Jaynes-Cummings model without the rotating-wave approximation can be mapped to
that of a polynomial equation with a single variable. The solutions to this
polynomial equation can give all eigenvalues and eigenfunctions of this model
with all values of the coupling strength and the detuning exactly, which can be
readily applied to recent circuit quantum electrodynamic systems operating in
the ultra-strong coupling regime.Comment: 6 pages,3 figure
Charge transfer and coherence dynamics of tunnelling system coupled to a harmonic oscillator
We study the transition probability and coherence of a two-site system,
interacting with an oscillator. Both properties depend on the initial
preparation. The oscillator is prepared in a thermal state and, even though it
cannot be considered as an extended bath, it produces decoherence because of
the large number of states involved in the dynamics. In the case in which the
oscillator is intially displaced a coherent dynamics of change entangled with
oscillator modes takes place. Coherency is however degraded as far as the
oscillator mass increases producing a increasingly large recoherence time.
Calculations are carried on by exact diagonalization and compared with two
semiclassical approximations. The role of the quantum effects are highlighted
in the long-time dynamics, where semiclassical approaches give rise to a
dissipative behaviour. Moreover, we find that the oscillator dynamics has to be
taken into account, even in a semiclassical approximation, in order to
reproduce a thermally activated enhancement of the transition probability
Excitations in time-dependent density-functional theory
An approximate solution to the time-dependent density functional theory
(TDDFT) response equations for finite systems is developed, yielding
corrections to the single-pole approximation. These explain why allowed
Kohn-Sham transition frequencies and oscillator strengths are usually good
approximations to the true values, and why sometimes they are not. The
approximation yields simple expressions for G\"orling-Levy perturbation theory
results, and a method for estimating expectation values of the unknown
exchange-correlation kernel.Comment: 4 pages, 1 tabl
Empathy and stress related neural responses in maternal decision making
Mothers need to make caregiving decisions to meet the needs of children, which may or may not result in positive child feedback. Variations in caregivers' emotional reactivity to unpleasant child-feedback may be partially explained by their dispositional empathy levels. Furthermore, empathic response to the child's unpleasant feedback likely helps mothers to regulate their own stress. We investigated the relationship between maternal dispositional empathy, stress reactivity, and neural correlates of child feedback to caregiving decisions. In Part 1 of the study, 33 female participants were recruited to undergo a lab-based mild stressor, the Social Evaluation Test (SET), and then in Part 2 of the study, a subset of the participants, 14 mothers, performed a Parenting Decision Making Task (PDMT) in an fMRI setting. Four dimensions of dispositional empathy based on the Interpersonal Reactivity Index were measured in all participants-Personal Distress, Empathic Concern, Perspective Taking, and Fantasy. Overall, we found that the Personal Distress and Perspective Taking were associated with greater and lesser cortisol reactivity, respectively. The four types of empathy were distinctly associated with the negative (vs. positive) child feedback activation in the brain. Personal Distress was associated with amygdala and hypothalamus activation, Empathic Concern with the left ventral striatum, ventrolateral prefrontal cortex (VLPFC), and supplemental motor area (SMA) activation, and Fantasy with the septal area, right SMA and VLPFC activation. Interestingly, hypothalamus-septal coupling during the negative feedback condition was associated with less PDMT-related cortisol reactivity. The roles of distinct forms of dispositional empathy in neural and stress responses are discussed
Time evolution of the Rabi Hamiltonian from the unexcited vacuum
The Rabi Hamiltonian describes a single mode of electromagnetic radiation
interacting with a two-level atom. Using the coupled cluster method, we
investigate the time evolution of this system from an initially empty field
mode and an unexcited atom. We give results for the atomic inversion and field
occupation, and find that the virtual processes cause the field to be squeezed.
No anti-bunching occurs.Comment: 25 pages, 8 figures, RevTe
Inflammation and Proliferation Act Together to Mediate Intestinal Cell Fusion
Cell fusion between circulating bone marrow-derived cells (BMDCs) and non-hematopoietic cells is well documented in various tissues and has recently been suggested to occur in response to injury. Here we illustrate that inflammation within the intestine enhanced the level of BMDC fusion with intestinal progenitors. To identify important microenvironmental factors mediating intestinal epithelial cell fusion, we performed bone marrow transplantation into mouse models of inflammation and stimulated epithelial proliferation. Interestingly, in a non-injury model or in instances where inflammation was suppressed, an appreciable baseline level of fusion persisted. This suggests that additional mediators of cell fusion exist. A rigorous temporal analysis of early post-transplantation cellular dynamics revealed that GFP-expressing donor cells first trafficked to the intestine coincident with a striking increase in epithelial proliferation, advocating for a required fusogenic state of the host partner. Directly supporting this hypothesis, induction of augmented epithelial proliferation resulted in a significant increase in intestinal cell fusion. Here we report that intestinal inflammation and epithelial proliferation act together to promote cell fusion. While the physiologic impact of cell fusion is not yet known, the increased incidence in an inflammatory and proliferative microenvironment suggests a potential role for cell fusion in mediating the progression of intestinal inflammatory diseases and cancer
Phase-dependent spectra in a driven two-level atom
We propose a method to observe phase-dependent spectra in resonance
fluorescence, employing a two-level atom driven by a strong coherent field and
a weak, amplitude-fluctuating field. The spectra are similar to those which
occur in a squeezed vacuum, but avoid the problem of achieving squeezing over a
solid angle. The system shows other interesting features, such as
pronounced gain without population inversion.Comment: 4 pages and 4 figures. Submitted to Phys. Rev. Let
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