QuGrav: Bringing gravitational waves to light with Qumodes

TL;DR

This paper introduces a novel quantum bosonic mode-based method for detecting high-frequency gravitational waves, potentially surpassing current limits and enabling new cosmological insights.

Contribution

It proposes using qumodes and the inverse Gertsenshtein effect for gravitational wave detection, enhancing sensitivity through quantum statistics and measurement techniques.

Findings

Can achieve sensitivities close to the cosmological bound at microwave frequencies.

Potential to surpass the cosmological bound with near-future technology.

Enhances current optical frequency detectors by an order of magnitude.

Abstract

We propose using qumodes, quantum bosonic modes, for detecting high-frequency gravitational waves via the inverse Gertsenshtein effect, where a gravitational wave resonantly converts into a single photon in a magnetized cavity. For an occupation number $n$ of the photon field in a qumode, the conversion probability is enhanced by a factor of $n+1$ due to Bose-Einstein statistics. Unlocking this increased sensitivity entails the ability to continuously prepare the qumode and perform non-demolition measurement on the qumode-qubit system within the qumode coherence time. Our results indicate that, at microwave frequencies and with existing technology, the proposed setup can attain sensitivities within 1.7 orders of magnitude of the cosmological bound. With anticipated near-future improvements, it has the potential to surpass this limit and pave the way for the first exploration of high-frequency cosmological gravitational wave backgrounds. At optical frequencies, it can enhance the sensitivity of current detectors by one order of magnitude. That further enhances their potential in reaching the single-graviton level.