arXiv subjects

Scott Aronson

Publications and source records attributed to Scott Aronson.

5 recordsLinked to original sources

arXiv2025

Thermal Noise Measurement Below the Standard Quantum Limit

We present a method characterizing thermal noise in an optical cavity independent from quantum noise despite the thermal noise falling below the quantum noise limit. Using this method, we measured the thermal noise contribution from a GaAs AlGaAs micro-mirror suspended on a GaAs cantilever microresonator when brought to a cryogenic temperature (approximately 25 K) and incorporated into a Fabry Perot cavity. An optical spring is formed in this optical cavity. Previously, this setup exploited an optical spring to produce a displacement sensitivity falling 2.8 dB below the free-mass standard quantum limit (SQL), as reported by Cullen et. al. Here we use a similar setup to measure thermal noise which fell a maximum of 5 dB below the SQL. This measurement, in turn, allowed for an investigation of quantum noise suppression resulting from the optical spring effect, falling a maximum of 10 dB below the SQL.

quant-ph↗

arXiv2024

Conditional Motional Squeezing of an Optomechanical Oscillator Approaching the Quantum Regime

Squeezed mechanical states are a highly coveted resource for quantum-enhanced sensing and serve as a compelling platform for probing the interplay between gravity and quantum mechanics. It has been predicted that a mechanical oscillator can be prepared into a quantum squeezed state if the applied measurement rate is fast relative to its mechanical resonance frequency. However, the experimental feasibility of this protocol has remained uncertain because of the difficulty in achieving low-frequency oscillators with sufficiently strong read-out. Here, we demonstrate that a careful selection of parameters in an optomechanical system, combined with optimal filtering techniques, enables the preparation of a 50 ng GaAs cantilever in a conditional classical squeezed state, achieving a minimum uncertainty of just 1.07 plus/minus 0.04 times the zero-point fluctuation level. This minimum variance is 3 orders of magnitude smaller than what has been achieved in previous experiments using the same protocol. Although we do not fully achieve the quantum squeezed regime, our demonstration provides definitive evidence that a measurement-based protocol is a practical and effective approach for the real-time preparation of macroscopic oscillators in quantum squeezed states.

quant-ph↗

arXiv2024

Optical Spring Tracking for Enhancing Quantum-Limited Interferometers

Modern interferometers such as LIGO have achieved sensitivities limited by quantum noise, comprised of radiation pressure and shot noise. To mitigate this noise, a static system is employed that minimizes the quantum noise within the measurement band. However, since gravitational wave inspiral signals are a single frequency changing over time, only noise at the chirp frequency needs to be minimized. Here we demonstrate dynamically tracking a target signal using an optical spring, resulting in an increased signal to noise ratio (SNR). We report on a SNR increase by up to a factor of 40 when compared to a static configuration.

quant-ph↗

arXiv2022

Surpassing the Standard Quantum Limit using an Optical Spring

Quantum mechanics places noise limits and sensitivity restrictions on physical measurements. The balance between unwanted backaction and the precision of optical measurements impose a standard quantum limit (SQL) on interferometric systems. In order to realize a sensitivity below the SQL, it is necessary to leverage a back-action evading measurement technique, or else exploit cancellations of any excess noise contributions at the detector. %Many proof of principle experiments have been performed, but only recently has an experiment achieved sensitivity below the SQL. In this work, we extend that initial demonstration and realize sub-SQL measurement sensitivity nearly two times better than previous measurements, and with architecture applicable to interferometric gravitational wave detectors. In fact, this technique is directly applicable to Advanced LIGO, which could observe similar effects with a detuned signal recycling cavity. By exploiting quantum correlations created by an optical spring, we measure a total sensitivity below the SQL by $\textbf{2.8}$ dB, corresponding to a reduction in the noise power by $\textbf{72}\pm\textbf{5.1}$ \% below the quantum limit. Through the use of a detuned optical spring, this noise reduction is tunable, allowing us to choose the desired range of frequencies that fall below the SQL. This result demonstrates access to sensitivities well below the SQL at frequencies ranges applicable to LIGO, with the potential to extend the reach of gravitational wave detectors further into the universe.

quant-ph↗

arXiv2022

Passive Laser Power Stabilization via an Optical Spring

Metrology experiments can be limited by the noise produced by the laser involved via small fluctuations in the laser's power or frequency. Typically, active power stabilization schemes consisting of an in-loop sensor and a feedback control loop are employed. Those schemes are fundamentally limited by shot noise coupling at the in-loop sensor. In this letter we propose to use the optical spring effect to passively stabilize the classical power fluctuations of a laser beam. In a proof of principle experiment, we show that the relative power noise of the laser is stabilized from approximately $2 \times 10^{-5}$ Hz$^{-1/2}$ to a minimum value of $1.6 \times 10^{-7}$ Hz$^{-1/2}$, corresponding to the power noise reduction by a factor of $125$. The bandwidth at which stabilization occurs ranges from $400$ Hz to $100$ kHz. The work reported in this letter further paves the way for high power laser stability techniques which could be implemented in optomechanical experiments and in gravitational wave detectors.

physics.optics↗