## Collision rates in near-resonant optical lattices

JOSA B, Vol. 20, Issue 5, pp. 1135-1140 (2003)

http://dx.doi.org/10.1364/JOSAB.20.001135

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### Abstract

We present a simple method for calculating the binary collision rate between atoms in near-resonant optical lattices. The method is based on Monte Carlo wave-function simulations, and the collision rate is obtained by monitoring the quantum flux beyond the average distance between the atoms. To illustrate the usefulness of the method, we calculate the collision rates for a wide range of occupation densities and various modulation depths of the lattice. The method presented here, combined with the semiclassical calculations accounting for intrawell collisions, can simplify the study of the effects of binary collisions on the dynamics of atomic clouds trapped in near-resonant optical lattices.

© 2003 Optical Society of America

**OCIS Codes**

(020.2070) Atomic and molecular physics : Effects of collisions

(020.7010) Atomic and molecular physics : Laser trapping

**Citation**

Jyrki Piilo, "Collision rates in near-resonant optical lattices," J. Opt. Soc. Am. B **20**, 1135-1140 (2003)

http://www.opticsinfobase.org/josab/abstract.cfm?URI=josab-20-5-1135

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- Naturally, the methods without the extra potential of Eq. (8) should be used when one wants to calculate the thermodynamical properties of an atomic cloud in the whole lattice. These methods are already well-known; the purpose here is to give a new method for calculation of the collision rate.
- See Ref. 18 for the details of the jump operators that are used in our implementation of the method.
- It takes a finite length of time before the atoms begin to accumulate in the accumulation region. This is due to the finite distance between the initial lattice site and the accumulation region; see Fig. 1. Thus there is a small time delay in the simulation before the accumulation curve in Fig. 2 begins to increase and achieves nonzero values. We emphasize that it is only the slope β of the accumulation curve that is relevant for the collision-rate calculation here.
- This is in agreement with the result given in Ref. 10 where the collisions are also a measure of atomic transport in a lattice.
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- P. M. Visser and G. Nienhuis, “Quantum transport of atoms in an optical lattice,” Phys. Rev. A 56, 3950–3960 (1997).

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