Is the gravitational field a quantized degree of freedom? It would be very satisfying to do a direct experimental test to answer this question. Unfortunately, as emphasized by Dyson, it is probably impossible to build a detector sensitive enough to detect single gravitons. I’ll give an overview of a more circuitous, but potentially feasible, experimental path to probe the quantization of the gravitational … Read More

We study the decay rate of a false vacuum in gauge theory at the one-loop level. We give semi-analytic formulas of the decay rate paying particular attention to the treatment of zero modes and renormalization. Our formulation is applicable to the general gauge theories, where the bounce consists of an arbitrary number of scalar fields. As examples of application, we calculate the … Read More

Abstract: Particles with masses of order Hubble during inflation create a distinct, oscillatory signal in the squeezed limit of the CMB bispectrum. A host of models have been studied that produce non-Gaussianities in this limit, with a goal of identifying targets for near-future probes of the CMB and large-scale structure. Yet fully leveraging this program, known as “cosmological collider” physics, as … Read More

Abstract: We study the solar emission of light dark sector particles that self-interact strongly enough to self-thermalize. The resulting outflow behaves like a fluid which accelerates under its own thermal pressure to highly relativistic bulk velocities in the solar system. Compared to the ordinary non-interacting scenario, the local outflow has a much higher number density and correspondingly a much lower … Read More