Abstract: We propose an externally imposed superlattice potential as a platform for manipulating topological phases, which has both advantages and disadvantages compared to a moire superlattice. In the first example, we apply the superlattice potential to the 2D surface of a 3D topological insulator. The superlattice potential creates tunable…

Raman scattering, invented at the end of the last pandemic, can provide a wealth of information on the fractional, magnetic, lattice and charge excitations at the heart of quantum materials and devices. I will first discuss how Raman provides direct evidence for coupled phonon-electron fluids in topological semimetals, helping to explain their…

Abstract: Twisted van der Waals materials provide a new venue to explore flat electronic bands and the interaction-driven states they host. While many such phases have been reported, little is known about their excitations or how they depend on externally applied fields. In this talk, I will present two examples where…

    Quantum processors of today are already capable of surpassing classical supercomputers on certain specialized tasks [1]. A current milestone for the quantum information science community is the fulfilment of…

We study the entanglement dynamics of quantum many-body systems at long times.

For upper bounds, we prove the following: (I) For any geometrically local Hamiltonian on a lattice, starting from a random product state the entanglement entropy almost never approaches the Page curve. (II) In a spin-glass model with random all-to-all…

Duality transformations have played a major role in our modern understanding of quantum phenomena.  In 3 spacetime dimensions, familiar examples of duality transformations include 1) Goldstone modes of the XY model being dual to a photon, and 2) dualities involving statistical transmutation.  It has become clear recently that both of these…

I will describe experiments probing magnetic states based on the spontaneous alignment of electron orbitals. Such orbital ferromagnetism may be a generic phenomena, but has, to date, found its fullest expression in graphene heterostructures in which the two dimensional orbits of electrons in distinct momentum space valleys provide the…

I will discuss recent  theoretical work on exciton physics in two-dimensional materials. First, I will focus on the neutral particle-hole pair excitations of correlated “orbital Chern insulators” recently detected in twisted bilayer graphene, whose approximately flat conduction and valence bands have equal and opposite non-zero Chern number…

 In this seminar I will discuss recent progress on the use of planar crystals with hundreds of ions as a platform for quantum simulation of spin and spin-boson models. The key idea is the use of a pair of lasers to couple two internal levels of the ions, that act as a spin½ degree of freedom, to the…

The interplay between symmetry and topology allows a rich variety of electronic phases.  For layered systems, symmetry under translation by one layer protects the 3D weak topological insulator, which can be viewed as a stack of 2D topological insulators and the 2D 'weak topological superconductor', which is a stack of 1D topological…

What can we learn about a many-body system when we measure every constituent particle? Current experiments with ultracold atoms provide snapshots of many-body states with single particle resolution. I will present a recent application of this method to study magnetic polarons in antiferromagnetic Mott insulators. In…

Building on the work of von Neumann and Wigner, M. Berry showed that there are topologically protected level-crossings in the space of quantum systems. These level-crossings can be detected using the curvature of the Berry connection. In this talk I will describe analogs of this for interacting lattice systems in infinite volume. Although the…

Quantum gas microscopes provide experimental access to novel observables, foremost, single particle resolved multi-point correlation functions. These offer a novel microscopic window into the physics of strongly correlated many-body physics. In our setup we developed a method for the simultaneous detection of spin and…

While driven interacting quantum matter is generically subject to heating and scrambling, certain classes of systems evade this paradigm. I will discuss such an exceptional class in periodically driven critical (1 + 1)-dimensional systems with a spatially modulated, but disorder-free time evolution operator. Instead of complete scrambling, the…

The search for topological matter is evolving towards strongly interacting systems including topological magnets and superconductors, where novel effects emerge from the quantum level interplay between geometry, correlation, and topology. Equipped with unprecedented spatial resolution, electronic detection, and…