9,403 research outputs found
Towards Constraining Parity-Violations in Gravity with Satellite Gradiometry
Parity violation in gravity, if existed, could have important implications,
and it is meaningful to search and test the possible observational effects.
Chern-Simons modified gravity serves as a natural model for gravitational
parity-violations. Especially, considering extensions to Einstein-Hilbert
action up to second order curvature terms, it is known that theories of
gravitational parity-violation will reduce to the dynamical Chern-Simons
gravity. In this letter, we outline the theoretical principles of testing the
dynamical Chern-Simons gravity with orbiting gravity gradiometers, which could
be naturally incorporated into future satellite gravity missions. The secular
gravity gradient signals, due to the Mashhoon-Theiss (anomaly) effect, in
dynamical Chern-Simons gravity are worked out, which can improve the constraint
of the corresponding Chern-Simons length scale
obtained from such measurement scheme. For orbiting superconducting
gradiometers or gradiometers with optical readout, a bound
(or even better) could in principle be
obtained, which will be at least 2 orders of magnitude stronger than the
current one based on the observations from the GP-B mission and the LAGEOS I,
II satellites.Comment: 15 pages, 6 figures. arXiv admin note: text overlap with
arXiv:1606.0818
The role of inter-well tunneling strength on coherence dynamics of two-species Bose-Einstein condensates
Coherence dynamics of two-species Bose-Einstein condensates in double wells
is investigated in mean field approximation. We show that the system can
exhibit decoherence phenomena even without the condensate-environment coupling
and the variation tendency of the degree of coherence depends on not only the
parameters of the system but also the initial states. We also investigate the
time evolution of the degree of coherence for a Rosen-Zener form of tunneling
strength, and propose a method to get a condensate system with certain degree
of coherence through a time-dependent tunneling strength
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