4,632 research outputs found
Damping of Josephson oscillations in strongly correlated one-dimensional atomic gases
We study Josephson oscillations of two strongly correlated one-dimensional
bosonic clouds separated by a localized barrier. Using a quantum-Langevin
approach and the exact Tonks-Girardeau solution in the impenetrable-boson
limit, we determine the dynamical evolution of the particle-number imbalance,
displaying an effective damping of the Josephson oscillations which depends on
barrier height, interaction strength and temperature. We show that the damping
originates from the quantum and thermal fluctuations intrinsically present in
the strongly correlated gas. Thanks to the density-phase duality of the model,
the same results apply to particle-current oscillations in a one-dimensional
ring where a weak barrier couples different angular momentum states
Local triple derivations on real C*-algebras and JB*-triples
We study when a local triple derivation on a real JB*-triple is a triple
derivation. We find an example of a (real linear) local triple derivation on a
rank-one Cartan factor of type I which is not a triple derivation. On the other
hand, we find sufficient conditions on a real JB*-triple E to guarantee that
every local triple derivation on E is a triple derivation
Single atom edge-like states via quantum interference
We demonstrate how quantum interference may lead to the appearance of robust
edge-like states of a single ultracold atom in a two-dimensional optical
ribbon. We show that these states can be engineered either within the manifold
of local ground states of the sites forming the ribbon, or of states carrying
one unit of angular momentum. In the former case, we show that the
implementation of edge-like states can be extended to other geometries, such as
tilted square lattices. In the latter case, we suggest to use the winding
number associated to the angular momentum as a synthetic dimension.Comment: 5 pages, 5 figure
Statistical analysis of entropy correction from topological defects in Loop Black Holes
In this paper we discuss the entropy of quantum black holes in the LQG
formalism when the number of punctures on the horizon is treated as a quantum
hair, that is we compute the black hole entropy in the grand canonical (area)
ensemble. The entropy is a function of both the average area and the average
number of punctures and bears little resemblance to the Bekenstein-Hawking
entropy. In the thermodynamic limit, both the "temperature" and the chemical
potential can be shown to be functions only of the average area per puncture.
At a fixed temperature, the average number of punctures becomes proportional to
the average area and we recover the Bekenstein-Hawking area-entropy law to
leading order provided that the Barbero-Immirzi parameter, , is
appropriately fixed. This also relates the chemical potential to . We
obtain a sub-leading correction, which differs in signature from that obtained
in the microcanonical and canonical ensembles in its sign but agrees with
earlier results in the grand canonical ensemble.Comment: 12 pages, no figures. Version to appear in Phys. Rev.
2-local triple homomorphisms on von Neumann algebras and JBW-triples
We prove that every (not necessarily linear nor continuous) 2-local triple
homomorphism from a JBW-triple into a JB-triple is linear and a triple
homomorphism. Consequently, every 2-local triple homomorphism from a von
Neumann algebra (respectively, from a JBW-algebra) into a C-algebra
(respectively, into a JB-algebra) is linear and a triple homomorphism
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