Title: Modeling the Electrodynamics of Charged Quantum Fluids in Heterogeneous Environments

Abstract: Charged quantum fluids appear in a wide variety of heterogeneous electromagnetic environments, ranging from macroscopic systems such as superconducting microwave circuits to the quantum electrodynamics (QED) that govern electron-positron creation and annihilation. Precise modeling of their dynamics is challenging due to (1) the inherent nonlinearity of the interactions and (2) the multiscale nature of the problem - either because the systems of interest extend over vast spatial scales as seen in superconducting circuits, or because of the multi-timescale evolutions that appear high-energy QED. In this talk, I will discuss an approach to modeling the nonlinear dynamics of charged fluids based on coarse-graining and hybridization. The method centers around formulating the dynamics in terms of gauge-invariant fields that hybridize the light and matter degrees of freedom. Discrete Exterior Calculus is leveraged to derive the equations of motion for the coarse-grained variables that encode experimentally accessible information. This allows for accurate and stable simulations of both transient and long-time dynamics in geometrically complex systems. In particular, here I will focus on two case studies: (1) dynamics of the superconducting condensate in Josephson junction-based microwave devices and (2) electron-position dynamics in the 1+1D Schwinger process. Within the former topic, I will discuss simulations of time-evolutions in superconducting devices and our approach in capturing radiative losses. Results on simulating the dynamics of fluxons in long Josephson junctions will also be presented. For the latter topic, I will focus on the emergence of atomic structure from 1+1D non-perturbative relativistic QED. The electromagnetic stability of Schwinger atoms and their radiative properties will be discussed.

Lunch will be provided at 12:30 PM in EQuad J401.