arXiv subjects

Luis Santos

Publications and source records attributed to Luis Santos.

95 records · Page 6Linked to original sources

arXiv2005

Bose-Einstein Condensates in Optical Quasicrystal Lattices

We analyze the physics of Bose-Einstein condensates confined in 2D quasi-periodic optical lattices, which offer an intermediate situation between ordered and disordered systems. First, we analyze the time-of-flight interference pattern that reveals quasi-periodic long-range order. Second, we demonstrate localization effects associated with quasi-disorder as well as quasiperiodic Bloch oscillations associated with the extended nature of the wavefunction of a Bose-Einstein condensate in an optical quasicrystal. In addition, we discuss in detail the crossover between diffusive and localized regimes when the quasi-periodic potential is switched on, as well as the effects of interactions.

cond-mat.other↗

arXiv1999

Reversible quantum teleportation in an optical lattice

We propose a protocol, based on entanglement procedures recently suggested by [D. Jaksch et al., Phys. Rev. Lett. 82, 1975 (1999)], which allows the teleportation of an unknown state of a neutral atom in an optical lattice to another atom in another site of the lattice, without any irreversible detection.

quant-ph↗

arXiv1999

Collisional effects on the collective laser cooling of trapped bosonic gases

We analyse the effects of atom-atom collisions on collective laser cooling scheme. We derive a quantum Master equation which describes the laser cooling in presence of atom-atom collisions in the weak-condensation regime. Using such equation, we perform Monte Carlo simulations of the population dynamics in one and three dimensions. We observe that the ground-state laser-induced condensation is maintained in the presence of collisions. Laser cooling causes a transition from a Bose-Einstein distribution describing collisionally induced equilibrium,to a distribution with an effective zero temperature. We analyse also the effects of atom-atom collisions on the cooling into an excited state of the trap.

quant-ph↗

arXiv1998

Bloch-Like Quantum Multiple Reflections of Atoms

We show that under certain circumstances an atom can follow an oscillatory motion in a periodic laser profile with a Gaussian envelope. These oscillations can be well explained by using a model of energetically forbidden spatial regions. The similarities and differences with Bloch oscillations are discussed. We demonstrate that the effect exists not only for repulsive but also for attractive potentials, i.e. quantum multiple reflections are also possible.

quant-ph↗

arXiv1998

Dynamical Cooling of Trapped Gases I: One Atom Problem

We study the laser cooling of one atom in an harmonic trap beyond the Lamb-Dicke regime. By using sequences of laser pulses of different detunings we show that the atom can be confined into just one state of the trap, either the ground state or an excited state of the harmonic potential. The last can be achieved because under certain conditions an excited state becomes a dark state. We study the problem in one and two dimensions. For the latter case a new cooling mechanism is possible, based on the destructive interference between the effects of laser fields in different directions, which allows the creation of variety of dark states. For both, one and two dimensional cases, Monte Carlo simulations of the cooling dynamics are presented.

quant-ph↗