Quantum transport in magneto-optical double-potential wells

We review the quantum transport of ultra-cold alkali atoms trapped in a one -dimensional optical lattice of double-potential wells, engineered through a combination of ac-Stark shifts and Zeeman interactions. The system is mod elled numerically through analysis of the bandstructure and integration of the time-dependent Schrodinger equation. By these means we simulate coheren t control of the atomic wavepackets. We present results from ongoing experi ments on laser-cooled caesium, including the demonstration of quantum state preparation and preliminary evidence for coherent tunnelling. Entanglement between the internal and motional degrees of freedom allows us to access t he tunnelling dynamics by Stern-Gerlach measurements of the ground state ma gnetic populations. A scheme to extend this into a full reconstruction of t he density matrix for the ground state angular momentum is presented. We fu rther consider the classical dynamics of our system, which displays determi nistic chaos. This has important implications for the distinction between c lassical and quantum mechanical transport.