Modular variable laser cooling for efficient entropy extraction

Abstract

We propose and experimentally demonstrate a method for laser cooling an oscillator based on sequences of spin-state-dependent displacements followed by spin repumping. For a thermal state with mean occupation $\bar{n}\gg 1$ the method attains a reduction to 0.632 of the initial thermal oscillator occupation for two repumps of the two-level spin state. This is within a factor of 2.53 of the optimum that might be expected due to the reduction of the oscillator entropy by $2\ln (2)$. We show that the method, which is based on encoding the value of the modular-variable of the oscillator into the spin, has a simple semi-classical description in terms of a Bayesian update. We demonstrate the method experimentally using the internal and motional states of a single trapped ion.

References in corpus (10)

• Cavity Optomechanics
• Laser cooling of a nanomechanical oscillator into its quantum ground state
• Encoding a qubit in an oscillator
• Laser cooling of a diatomic molecule
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• Towards fault-tolerant quantum computing with trapped ions
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Cited by in corpus (1)

• Symmetry-controlled thermal activation in pyramidal Coulomb clusters: Testing Kramers-Langer theory