Quantum-enhanced Measurement using Optomechanical Sensors for Gravitational Direct Detection of Dark Matter

Recent advances in mechanical sensing technologies have recently led to the suggestion that heavy dark matter candidates — around the Planck mass range — could be detected through their gravitational interaction alone. With this ultimate goal on the horizon, the Windchime collaboration is involved in developing the necessary techniques, systems, and experimental apparatus using arrays of optomechanical sensors. These can also be used to investigate non- gravitational signals from other dark matter candidates in the near-term. However, to achieve Planck-scale detection, measurements of these devices much exceed the standard quantum limit. Hence we need to employ quantum-enhanced readout techniques for detecting the extremely weak impulse transfers from the gravitational interaction of dark matter. Here we discuss the different techniques of achieving such quantum-enhanced measurements including an optomechanical measurement combining backaction evasion and squeezing. This would help us in reducing the measurement-added noise floor in experimentally relevant parameter regimes in order to reach our desired sensitivity.