We consider the possibility that gravity is mediated by “continuous spin” particles, i.e. massless particles whose invariant spin scale ${\rho }_g$ is nonzero. In this case, the primary helicity-2 modes of gravitational radiation on a Minkowski background mix with a tower of integer-helicity partner modes under boosts, with ${\rho }_g$ controlling the degree of mixing. We develop a formalism for coupling spinless matter to continuous spin gravity at linearized level. Using this formalism, we calculate the time-delay signatures induced by gravitational waves in an idealized laser interferometer detector. The fractional deviation from general relativity predictions is $O({\rho }_g/\omega )$ for gravitational wave frequencies $\omega >{\rho }_g$, and the effects of waves with $\omega \lesssim {\rho }_g$ are damped. The precision and low frequency ranges of gravitational wave detectors suggest potential sensitivity to spin scales at or below $\sim {10}^{-14}\mathrm{eV}$ at ground-based laser interferometers and $\sim {10}^{-24}\mathrm{eV}$ at pulsar timing arrays, motivating further analysis of observable signatures.

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• Classical solutions in field theory
• Field & string theory models & techniques
• Gravitational waves
• Phenomenology