2,060 research outputs found
Stability, effective dimensions, and interactions for bosons in deformed fields
The hyperspherical adiabatic method is used to derive stability criteria for
Bose-Einstein condensates in deformed external fields. An analytical
approximation is obtained. For constant volume the highest stability is found
for spherical traps. Analytical approximations to the stability criterion with
and without zero point motion are derived. Extreme geometries of the field
effectively confine the system to dimensions lower than three. As a function of
deformation we compute the dimension to vary continuously between one and
three. We derive a dimension-dependent effective radial Hamiltonian and
investigate one choice of an effective interaction in the deformed case.Comment: 7 pages, 5 figures, submitted to Phys. Rev. A. In version 2 figures 2
and 5 are added along with more discussions and explanations. Version 3
contains added comments and reference
Condensates and correlated boson systems
We study two-body correlations in a many-boson system with a hyperspherical
approach, where we can use arbitrary scattering length and include two-body
bound states. As a special application we look on Bose-Einstein condensation
and calculate the stability criterium in a comparison with the experimental
criterium and the theoretical criterium from the Gross-Pitaevskii equation.Comment: 6 pages, 4 figures. Contribution to Workshop on Critical Stability
III in Trento. Submitted to Few-Body System
Teleportation in an indivisible quantum system
Teleportation protocol is conventionally treated as a method for quantum
state transfer between two spatially separated physical carriers. Recent
experimental progress in manipulation with high-dimensional quantum systems
opens a new framework for implementation of teleportation protocols. We show
that the one-qubit teleportation can be considered as a state transfer between
subspaces of the whole Hilbert space of an indivisible eight-dimensional
system. We explicitly show all corresponding operations and discuss an
alternative way of implementation of similar tasks.Comment: 4 pages, 1 figure, 1 tabl
alpha particle momentum distributions from 12C decaying resonances
The computed particle momentum distributions from the decay of
low-lying C resonances are shown. The wave function of the decaying
fragments is computed by means of the complex scaled hyperspherical adiabatic
expansion method. The large-distance part of the wave functions is crucial and
has to be accurately calculated. We discuss energy distributions, angular
distributions and Dalitz plots for the , and states of
C.Comment: 6 pages, 4 figures. Proceedings of the SOTANCP2008 conference held in
Strasbourg in May 200
Structure and three-body decay of Be resonances
The complex-rotated hyperspherical adiabatic method is used to study the
decay of low-lying Be resonances into one neutron and two
-particles. We investigate the six resonances above the break-up
threshold and below 6 MeV: , and . The
short-distance properties of each resonance are studied, and the different
angular momentum and parity configurations of the Be and He two-body
substructures are determined. We compute the branching ratio for sequential
decay via the Be ground state which qualitatively is consistent with
measurements. We extract the momentum distributions after decay directly into
the three-body continuum from the large-distance asymptotic structures. The
kinematically complete results are presented as Dalitz plots as well as
projections on given neutron and -energy. The distributions are
discussed and in most cases found to agree with available experimental data.Comment: 12 pages, 10 figures. To appear in Physical Review
Post-processing procedure for industrial quantum key distribution systems
We present algorithmic solutions aimed on post-processing for industrial
quantum key distribution systems with hardware sifting. The main steps of the
procedure are error correction, parameter estimation, and privacy
amplification. Authentication of a classical public communication channel is
also considered.Comment: 5 pages; presented at the 3rd International School and Conference
"Saint-Petersburg OPEN 2016" (Saint-Petersburg, March 28-30, 2016
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