746 research outputs found
Nonclassical dynamics of Bose condensates in an optical lattice in the superfluid regime
A condensate in an optical lattice, prepared in the ground state of the
superfluid regime, is stimulated first by suddenly increasing the optical
lattice amplitude and then, after a waiting time, by abruptly decreasing this
amplitude to its initial value. Thus the system is first taken to the Mott
regime and then back to the initial superfluid regime. We show that, as a
consequence of this nonadiabatic process, the system falls into a configuration
far from equilibrium whose superfluid order parameter is described in terms of
a particular superposition of Glauber coherent states that we derive. We also
show that the classical equations of motion describing the time evolution of
this system are inequivalent to the standard discrete nonlinear Schreodinger
equations. By numerically integrating such equations with several initial
conditions, we show that the system loses coherence, becoming insulating.Comment: 5 pages, 4 figure
Quantum correlations of two optical fields close to electromagnetically induced transparency
We show that three-level atoms excited by two cavity modes in a
configuration close to electromagnetically induced transparency can produce
strongly squeezed bright beams or correlated beams which can be used for
quantum non demolition measurements. The input intensity is the experimental
"knob" for tuning the system into a squeezer or a quantum non demolition
device. The quantum correlations become ideal at a critical point characterized
by the appearance of a switching behavior in the mean fields intensities. Our
predictions, based on a realistic fully quantum 3-level model including cavity
losses and spontaneous emission, allow direct comparison with future
experiments.Comment: 4 pages, 5 figure
Squeezing and entangling nuclear spins in helium 3
We present a realistic model for transferring the squeezing or the
entanglement of optical field modes to the collective ground state nuclear spin
of He using metastability exchange collisions. We discuss in detail the
requirements for obtaining good quantum state transfer efficiency and study the
possibility to readout the nuclear spin state optically
Evolution of the macroscopically entangled states in optical lattices
We consider dynamics of boson condensates in finite optical lattices under a
slow external perturbation which brings the system to the unstable equilibrium.
It is shown that quantum fluctuations drive the condensate into the maximally
entangled state. We argue that the truncated Wigner approximation being a
natural generalization of the Gross-Pitaevskii classical equations of motion is
adequate to correctly describe the time evolution including both collapse and
revival of the condensate.Comment: 14 pages, 10 figures, Discussion of reversibility of entanglement is
adde
Genuine phase diffusion of a Bose-Einstein condensate in the microcanonical ensemble: A classical field study
Within the classical field model, we find that the phase of a Bose-Einstein
condensate undergoes a true diffusive motion in the microcanonical ensemble,
the variance of the condensate phase change between time zero and time
growing linearly in . The phase diffusion coefficient obeys a simple scaling
law in the double thermodynamic and Bogoliubov limit. We construct an
approximate calculation of the diffusion coefficient, in fair agreement with
the numerical results over the considered temperature range, and we extend this
approximate calculation to the quantum field.Comment: 9 pages, 6 figure
Non-diffusive phase spreading of a Bose-Einstein condensate at finite temperature
We show that the phase of a condensate in a finite temperature gas spreads
linearly in time at long times rather than in a diffusive way. This result is
supported by classical field simulations, and analytical calculations which are
generalized to the quantum case under the assumption of quantum ergodicity in
the system. This super-diffusive behavior is intimately related to conservation
of energy during the free evolution of the system and to fluctuations of energy
in the prepared initial state.Comment: 16 pages, 7 figure
Entanglement properties of degenerate four-wave mixing of matter-waves in a periodic potential
In a recent experiment Campbell et al. [Phys. Rev. Lett. 96, 020406 (2006)]
observed degenerate four-wave mixing of matter-waves in a one-dimensional
optical lattice, a process with potential for generating entanglement among
atoms. We analyse the essential quantum features of the experiment to show that
entanglement is created between the quadratures of the two scattered atomic
clouds and is a true many-body (rather than two-body) effect. We demonstrate a
significant violation of entanglement inequalities that is robust to a moderate
level of coherent seeding. The system is thus a promising candididate for
generating macroscopically entangled atomic samples.Comment: 4 pages, 3 figure
To What Extend Does the Technology Disrupstion Affect the Sale of Smes Banana Chips Products in Bandar Lampung?
Small and Medium-Sized Enterprises (SMEs) in Indonesia, which is also known as Usaha Mikro Kecil dan Menengah (UMKM), play a significant role in determining national economic performance. Banana chips are the most well-known product in Bandar Lampung. As the provincial capital of Lampung Province, Bandar Lampung becomes the center of trade and services sector which is a vital sector of the downstream industry activity. One of the vital aspect in the downstream of Banana chips industry is selling. This study aims to examine the effect of disruptive technology on the sale of SMEs Banana Chips products in Bandar Lampung. This study conduct the quantitative approach by using multiple regression linear analysis. The findings show that the regression model of selling aspect has 0.594 in R2 value. It means that the regression model is able to represent the real condition about 59,4%. According to the model, among the 6 (six) predictor variables, the most-influencing variable on the sale of Banana chips products is online-based promotion
Defective phagocytic corpse processing results in neurodegeneration and can be rescued by TORC1 activation
This work was supported by NIH Grants R01 GM094452 (K.M.) and F31 GM099425 (J.I.E.), BU Alzheimer's Disease Core Center NIH Grant P30 AG13846, Boston University Undergraduate Research Opportunities Program grants (J.A.T., V.S.), and NIH Grant R01 AG044113 to M.B.F. We thank the Bloomington Stock Center, TRiP at Harvard Medical School, the Kyoto Drosophila Genetic Resource Center, Estee Kurant, Eric Baehrecke, Marc Freeman, and Mary Logan for fly strains. We thank Todd Blute for assistance with electron microscopy and the Developmental Studies Hybridoma Bank for antibodies. (R01 GM094452 - NIH; F31 GM099425 - NIH; R01 AG044113 - NIH; P30 AG13846 - BU Alzheimer's Disease Core Center NIH Grant; Boston University Undergraduate Research Opportunities Program)https://www.jneurosci.org/content/36/11/3170.longPublished versionPublished versio
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