# Highly efficient cooling of mechanical resonator with square pulse drives

## TL;DR

This paper demonstrates that using square pulse drives in optomechanical systems enables more efficient and flexible ground state cooling of mechanical resonators, surpassing continuous-wave methods in speed and effectiveness.

## Contribution

It introduces a novel square pulse drive scheme for optomechanical cooling, optimizing pulse parameters to achieve faster ground state cooling than traditional continuous-wave approaches.

## Key findings

- Square pulse drives can cool mechanical resonators more efficiently than continuous-wave drives.
- Thermal phonon numbers can drop below the continuous-wave theoretical limit.
- Optimized pulse parameters significantly improve cooling speed and effectiveness.

## Abstract

Ground state cooling of mechanical resonator is a way to generate macroscopic quantum states. Here we present a study of optomechanical cooling under the drive of square pulses without smooth profile. By illustrating the dynamical processes of cooling, we show how to choose the amplitudes and durations of square pulses, as well as the intervals between them, so that a mechanical resonator can be quickly cooled down to its ground state. Compared with the cooling under a continuous-wave drive field, the ground state cooling of a mechanical resonator can be performed more efficiently and flexibly by using square pulse drives. At certain times of such cooling process, the thermal phonon number under square pulse drives can become even lower than the theoretical limit for the cooling with a continuous-wave drive field of the same amplitude.