Cold atoms in optical lattices :a Hamiltonian ratchet

T. S. Monteiro; P. A. Dando; N. A. C. Hutchings; M. R. Isherwood

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Cold atoms in optical lattices :a Hamiltonian ratchet

T. S. Monteiro·P. A. Dando·N. A. C. Hutchings·M. R. Isherwood

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Abstract

We investigate a new type of quantum ratchet which may be realised by cold atoms in a double-well optical lattice which is pulsed with unequal periods. The classical dynamics is chaotic and we find the classical diffusion rate $D$ is asymmetric in momentum up to a finite time $t_r$. The quantum behaviour produces a corresponding asymmetry in the momentum distribution which is 'frozen-in' by Dynamical Localisation provided the break-time $t^* > t_r$. We conclude that the cold atom ratchets require $Db/ \hbar \sim 1$ where b is a small deviation from period-one pulses.

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T. S. Monteiro, P. A. Dando, N. A. C. Hutchings, M. R. Isherwood. 2002-03-27. Cold atoms in optical lattices :a Hamiltonian ratchet. https://arxiv.org/abs/physics/0203056

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