2 research outputs found
Bose-Einstein condensates in 1D optical lattices: compressibility, Bloch bands and elementary excitations
We discuss the Bloch-state solutions of the stationary Gross-Pitaevskii
equation and of the Bogoliubov equations for a Bose-Einstein condensate in the
presence of a one-dimensional optical lattice. The results for the
compressibility, effective mass and velocity of sound are analysed as a
function of the lattice depth and of the strength of the two-body interaction.
The band structure of the spectrum of elementary excitations is compared with
the one exhibited by the stationary solutions (``Bloch bands''). Moreover, the
numerical calculations are compared with the analytic predictions of the tight
binding approximation. We also discuss the role of quantum fluctuations and
show that the condensate exhibits 3D, 2D or 1D features depending on the
lattice depth and on the number of particles occupying each potential well. We
finally show how, using a local density approximation, our results can be
applied to study the behaviour of the gas in the presence of harmonic trapping.Comment: version published in EPJ
Quantum Technologies: Implications for European Policy: Issues for debate
New technologies for communications, computing, sensing and timing, which exploit quantum physics more deeply than heretofore, are expected to have high impact and to require a European policy response. This paper raises key discussion points, as a contribution to a wider EC initiative.JRC.G.5-Security technology assessmen