Subjects: Physics >> The Physics of Elementary Particles and Fields submitted time 2016-05-08
Abstract: We use the爏tochastic燼pproach to investigate燼爉easure爁or爏low roll爀ternal爄nflation. The probability爁or爐he universe to have燼爂iven Hubble radius can be calculated in this framework. In燼爏olvable model, it is shown that the probability爁or爐he universe to evolve from燼爏tate with燼爏maller Hubble radius to one with燼爈arger Hubble radius is dominated by the classical probability without the爏tochastic爏ource, while the probability爁or爐he universe to evolve from燼爏tate with燼爈arger Hubble radius to one with燼爏maller one is suppressed by exp(-Delta S), where the de Sitter entropy S arises naturally in this爏tochasticapproach.
Peer Review Status:Awaiting Review
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2016-05-08
Abstract: Small regulatory RNA (sRNA) that acts by an antisense mechanism is critical for gene regulation at the posttranscriptional level. Recently, an Hfq-dependent sRNA named MicM, which is related to the regulation of outer membrane protein, was verified as a novel antisense sRNA due to its catalytic mode of regulation. Here we propose a simple kinetic model for the enzyme-like regulation mode of sRNA and study in detail the noise properties of the target gene under various recycling rates of the regulator. We predict that the recycling rate of sRNA and other relative parameters have significant influence on the noise strength of target expression. In comparison with the stoichiometric regulatory mode, a lesser fluctuation of target expression was observed near the threshold at which the transcription rates of both sRNA and target mRNA equal each other. We also found that the new mode is better in terms of rapid response to external signals. However, it needs more time to achieve target recovery if the stimulating signal disappears. Additionally, the obtained time evolution results of the MicM-ybfM interaction system based on our model are consistent with previous experimental results, serving as experimental evidence to back up our theoretical analysis. (C) 2010 Elsevier Ltd. All rights reserved.
Peer Review Status:Awaiting Review
Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties submitted time 2016-05-08
Abstract: By including the contribution of the thermal cloud in the Lagrangian of the condensate of a Bose gas, we extend the time-dependent variational method at zero temperature to study temperature-dependent low collective excitation modes. A Gaussian trial wave function of the condensate and a static distribution density of the thermal cloud are used and analytical expressions for temperature-dependent excitation frequencies obtained. Theoretical results are compared with measurements in the JILA and MIT experiments.
Peer Review Status:Awaiting Review
Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties submitted time 2016-05-08
Abstract: A Bose gas in an external potential is studied by means of the local density approximation. Analytical results are derived for the thermodynamic properties of an ideal Bose gas in a generic power-law trapping potential, and their dependence on the mutual interaction of atoms in the case of a non-ideal Bose gas.
Peer Review Status:Awaiting Review
Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties submitted time 2016-05-08
Abstract: A Bose gas in an external potential is studied by means of the semiclassical approximation. Analytical results are derived for the energy of an interacting Bose gas in a generic power-law trapping potential. An expression for the chemical potential below the critical temperature is also obtained. The theoretical results are in agreement with a recent energy measurement.
Peer Review Status:Awaiting Review
Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties submitted time 2016-05-08
Abstract: The behavior of a trapped燼tomic爂as爑ndergoing a燘ose-Einstein燾ondensation爄s strongly influenced by the燼ttractive爄nteraction between particles. The role played by such燼n爄nteraction is analyzed by means of a variation method. The critical number of atoms for a metastable state to exist is determined, The aspect ratio of condensed bosons爄n燼n燼nisotropic trap, the loss rate of atoms, and the excitation spectrum are studied. The vortex state is discussed.
Peer Review Status:Awaiting Review