Physics

The study of black holes has revealed a deep connection between quantum information and spacetime geometry. Its origin must lie in a quantum theory of gravity, so it offers a valuable hint in our search for a unified theory. Precise formulations of this relation recently led to new insights in Quantum Field Theory, some of which have been rigorously proven. An important example is our discovery of the first universal lower bound on the local energy density. The energy near a point can be negative, but it is bounded below by a quantity related to the information flowing past the point.

One of the most enduring mysteries in particle physics is the nature of the non-baryonic dark matter that makes up 85% of the matter in the universe. For several decades, most searches for this mysterious substance have focused on Weakly Interacting Massive Particles (WIMPs). Recently, there has been a surge in theoretical interest in ultra-light-field dark matter candidates, including QCD axions (spin 0 bosons) and hidden photons (spin 1 bosons), which can be probed through their coupling to electromagnetism or nuclear spin. I will discuss general principles of efficiently searching for the direct detection of the electromagnetic coupling of these candidates, how the sensitivity of these experiments can be improved by the exploitation of quantum correlations in the electromagnetic signals that they produce, and describe the Dark Matter Radio, and experiment searching for axions and hidden photons in the frequency range of 1 kHz through 100 MHz.