Gravitational wave detection via photon-graviton scattering and quantum interference

TL;DR

The paper develops a fully quantum-field description of gravitational-wave detection via photon-graviton scattering, treating the GW as a coherent quantum background that mediates inelastic energy exchange with photons and induces a GW-dependent phase. It shows that the resulting phase accumulation $\phi_{\mathbf{k}}(t)$ reduces to the classical optical-path delay $-\omega_{\mathbf{k}} (1/2)\int_0^t h_{\mathrm{eff}}(t') dt'$ in the coherent GW limit, thereby reproducing standard antenna patterns. The authors propose a Hong-Ou-Mandel interference scheme to read out GW signals from GW-induced distinguishability, deriving the linear-response regime with a slope $\mathcal{K}(\sigma,\Delta\tau_0)$ and photon-coincidence readout $\delta N_c$. They analyze 2D planar and 3D pyramidal detector configurations, showing that a triad network yields near-isotropic, full-sky sensitivity and enhanced source localization. The work highlights experimental prospects, arguing for space-based implementations where long baselines and quantum-coherence techniques can realize a complementary quantum probe of the gravitational universe.

Abstract

We present a fully quantum field-theoretic framework for gravitational wave (GW) detection in which the interaction is described as photon-graviton scattering. In this picture, the GW acts as a coherent background that induces inelastic energy exchanges with the electromagnetic field - analogous to the Stokes and anti-Stokes shifts in Raman spectroscopy. We propose a detection scheme sensitive to this microscopic mechanism based on Hong-Ou-Mandel interference. We show that the scattering-induced phase shifts render frequency-entangled photon pairs distinguishable, spoiling their destructive quantum interference. GW signal is thus encoded in the modulation of photon coincidence rates rather than classical field intensity, offering a complementary quantum probe of the gravitational universe that recovers the standard classical response in the macroscopic limit.

Figures (6)

• Figure 1: Schematic diagram of the inelastic graviton scattering.
• Figure 2: Schematic diagram of effective differential time delay in the HOM-type experiment.
• Figure 3: Illustration of the slope detection vs. quadratic detection.
• Figure 4: Possible geometrical configurations in 2D and 3D for HOM based GW detectors.
• Figure 5: Directional sensitivity (antenna patterns) for the three individual detectors in the pyramidal configuration ($\vartheta = \pi/6$). Unlike planar detectors which share common null directions, the 3D geometry ensures that the maxima of one detector cover the minima of the others.