Condensed Matter Theory Seminar - Patrick Ledwith - MIT
Controlled expansion for correlated electrons with concentrated kinematics
We will discuss a systematic expansion tailored towards systems with strong local interactions and capable of computing response functions, including DC transport, analytically. The expansion is controlled by a small parameter “s2” that measures the area of the momentum space where kinematics of the theory is concentrated.
We will motivate the expansion with its application to twisted bilayer graphene, where the small parameter corresponds to the width of the Berry curvature distribution. Here, the expansion predicts the emergence of "Dirac Trion" excitations: three-body bound states of heavy particles that are nonetheless arbitrarily light. We will then describe how to carry out the expansion to higher orders, its regime of validity, and the potential to shed light on conceptual mysteries associated with systems with Mott correlations.
Biography: Patrick Ledwith is a MIT Pappalardo fellow in Physics with broad interest in the theory of quantum many-body systems. He did his PhD at Harvard with Ashvin Vishwanath where he worked on strongly interacting electrons in topological bands and proposed realizations in moiré systems. Previously, while an undergraduate at MIT, he worked with Leonid Levitov on long-lived excitations in two-dimensional Fermi liquids and their impact on hydrodynamic transport.
Host: Leonid Glazman
