Direct cooling in an optical lattice by amplitude modulation

TL;DR

This paper introduces a novel cooling method for atoms in optical lattices using amplitude modulation to selectively remove high-energy atoms in quasi-momentum space, enabling direct condensation and enhancing quantum simulation capabilities.

Contribution

The study presents a new amplitude modulation technique for cooling atoms in optical lattices by quasi-momentum filtering, distinct from traditional position-space methods.

Findings

Effective removal of energetic atoms through frequency-swept modulation.

Achieved direct condensation of thermal atoms in optical lattices.

Provides a complementary cooling mechanism for quantum gases.

Abstract

We report on a generic cooling technique for atoms trapped in optical lattices. It consists in modulating the lattice depth with a proper frequency sweeping. This filtering technique removes the most energetic atoms, and provides with the onset of thermalization a cooling mechanism reminiscent of evaporative cooling. However, the selection is here performed in quasi-momentum space rather than in position space. Interband selection rules are used to protect the population with a zero quasi-momentum, namely the Bose Einstein condensate. Direct condensation of thermal atoms in an optical lattice is also achieved with this technique. It offers an interesting complementary cooling mechanism for quantum simulations performed with quantum gases trapped in optical lattices.