# Optomechanical oscillator controlled by variation in its heat bath temperature

## TL;DR

This paper explores how varying the temperature of the heat bath influences a quantum optomechanical oscillator, enabling the generation of low-noise states through bath temperature control and thermodynamic analysis.

## Contribution

It introduces a method to control an optomechanical oscillator's noise level by adjusting the heat bath temperature, linking thermodynamic properties with mechanical states.

## Key findings

- Temperature variation shifts the membrane's equilibrium position.
- Increasing temperature enhances fluctuations in the membrane.
- Cooling the membrane reduces thermal noise, achieving low-noise states.

## Abstract

We propose a generation of a low-noise state of optomechanical oscillator by a temperature dependent force. We analyze the situation in which a quantum optomechanical oscillator (denoted as the membrane) is driven by an external force (produced by the piston). Both systems are embedded in a common heat bath at certain temperature $T$. The driving force the piston exerts on the membrane is bath temperature dependent. Initially, for $T=T_0$, the piston is linearly coupled to the membrane. The bath temperature is then reversibly changed to $T\neq T_0$. The change of temperature shifts the membrane, but simultaneously also increases its fluctuations. The resulting equilibrium state of the membrane is analyzed from the point of view of mechanical, as well as of thermodynamic characteristics. We compare these characteristics of membrane and derive their intimate connection. Next, we cool down the thermal noise of the membrane, bringing it out of equilibrium, still being in the contact with heat bath. This cooling retains the effective canonical Gibbs state with the effective temperature $T^\star$. In such case we study the analogs of the equilibrium quantities for low-noise mechanical states of the membrane.