2007/10/31 by Alexander Klein, Martin Bruderer, Stephen R. Clark +2 · 1 citation
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Semiconductor Quantum Structures and Devices #Strong Light-Matter Interactions #quant-ph
paper · pdf · doi:10.1088/1367-2630/9/11/411
published as New J. Phys. 9, 411 (2007) · 22 pages, 8 figures, some typos corrected
openalex publication_date 2007/11/21 · arxiv created 2007/11/22 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We investigate the influence of a Bose–Einstein condensate (BEC) on the properties of immersed impurity atoms, which are trapped in an optical lattice. Assuming a weak coupling of the impurity atoms to the BEC, we derive a quantum master equation (QME) for the lattice system. In the special case of fixed impurities with two internal states the atoms represent a quantum register and the QME reproduces the exact evolution of the qubits. We characterize the qubit dephasing which is caused by the interspecies coupling and show that the effect of sub- and super-decoherence is observable for realistic experimental parameters. Furthermore, the BEC phonons mediate an attractive interaction between the impurities, which has an important impact on their spatial distribution. If the lattice atoms are allowed to move, there occurs a sharp transition with the impurities aggregating in a macroscopic cluster at experimentally achievable temperatures. We also investigate the impact of the BEC on the transport properties of the impurity atoms and show that a crossover from coherent to diffusive behaviour occurs with increasing interaction strength.