Speaker
Description
In this talk, I will present two novel theoretical ideas to search for dark matter (DM) across qualitatively distinct regions of model space with a genuine quantum sensing technique: matter-wave interferometry. I will begin by presenting new theoretical work establishing the in-in (Schwinger-Keldysh) formalism as the natural language for matter-wave interferometry, e.g., demonstrating how it elucidates coherent enhancements and the conditions under which they arise. I will then show how a trapped-ion interferometer, originally conceived for rotation sensing, would be sensitive to Rutherford scattering of sub-GeV millicharged particle DM with large effective electric charge off a heavy ion via collisional decoherence. Since these detectors are effectively threshold-free, trapped-ion interferometers are poised to outperform existing ion-trap and other direct detection experiments across a substantial region of parameter space. I will further show that tabletop experiments designed to test the quantum nature of gravity via gravity-induced entanglement between two massive wavepackets are naturally sensitive to quadratically-coupled scalar DM. Indeed, DM coupling to nucleons generates a position-dependent in-medium potential proportional to the DM occupation number which, at the wave-particle boundary (i.e., for DM masses ~ 10 eV), would entangle two otherwise uncorrelated masses, thus constituting a qualitatively new observable.
| Main Contribution topic | Theory / Phenomenology |
|---|---|
| Secondary contribution topic | Direct detection |