Superradiant interactions of cosmic relics

About

A large ensemble of two-level systems where each is prepared in an equal superposition of ground and excited states is the quantum analogue of a classical oscillating dipole. Scattering of weakly interacting particles off such a dipole is dramatically enhanced due to collective effects analogous to Dicke superradiance, where the de-excitation and excitation rates of the ensemble scale as the square of the number of particles in the system, $N^2$. The term ``superradiant interactions'' was coined to describe these coherent inelastic processes. Furthermore, because of this collective enhancement, scattering can quickly become non-perturbative, as $N$ is increased. In this talk, I will explain the theory behind coherent inelastic processes, both in the perturbative and non-perturbative regimes, and derive observables appropriate for table-top experiments. Next, I will discuss a forthcoming proposal for demonstrating these effects utilizing thermal neutrons. Finally, if time permits, I will introduce a quantum protocol for nuclear spin squeezing that may allow us to probe a variety of Beyond the Standard Model particles, including QCD axion Dark Matter and the irreducible abundance of millicharged particles.

00:00:00 Slide 1

00:02:26 Slide 2

00:03:29 Slide 3

00:03:54 Slide 4

00:04:08 Slide 5

00:04:28 Slide 6

00:05:23 Slide 7

00:05:48 Slide 8

00:06:19 Slide 9

00:08:20 Slide 10

00:09:39 Slide 11