I will present an overview of the current theoretical understanding of the remarkable phenomenology of the twisted bilayer graphene (TBG) near the magic angle. This includes the early insights obtained using the 2D exponentially localized Wannier basis[1] which revealed a qualitative difference between the effect of the...

# Events Archive

## Condensed Matter Seminar

### Condensed Matter Seminar - "Interplay of correlations and topology in the narrow bands of twisted bilayer graphene" Oskar Vafek, Florida State University

### Special Condensed Matter Seminar - Yichen Huang, MIT, "Entanglement dynamics from random product states at long times"

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

### Condensed Matter Zoom Seminar | Srinivas Raghu, Stanford | "Lattice constructions of a web of dualities in 3 spacetime dimensions"

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...

### Condensed Matter Zoom Seminar | Andrea Young, UCSB | "Orbital magnetism in graphene heterostructures"

I will describe experiments probing magnetic states based on the spontaneous alignment of electron orbitals.

### Condensed Matter Zoom Seminar | Siddharth Parameswaran | "Topology and broken symmetry of excitons in two-dimensional materials"

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.

### Condensed Matter Zoom Seminar | Ana Maria Rey, U Colorado | "Advances in Quantum Simulation with Planar Ion Crystals"

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.

### Condensed Matter Zoom Seminar | Claudio Chamon, Boston U. | "TBA"

TBA

### Condensed Matter Zoom Seminar | Charles Kane, U Penn.| "Translation symmetry enriched topological phases"

The interplay between symmetry and topology allows a rich variety of electronic phases.

### Condensed Matter Zoom Seminar | Eugene Demler, Harvard | "A new perspective on magnetic polarons from cold atoms"

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.

### Condensed Matter Zoom Seminar | Anton Kapustin, Caltech | "Higher-dimensional generalizations of the Berry curvature for gapped lattice systems"

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.

### Condensed Matter Zoom Seminar | Christian Gross, U of Tuebingen | "Microscopic spin and density cross-correlations in the Hubbard systems"

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.

### Condensed Matter Zoom Seminar | Titus Neupert,UZH | "Heating and blackhole dynamics in critical Floquet systems"

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.

### Condensed Matter Zoom Seminar | Jiaxin Yin | "Tunneling into emergent topological matter"

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.

### Condensed Matter Zoom Seminar | Johnpierre Paglione, U of MD | "Exotic superconductivity in nearly ferromagnetic UTe2"

Topological superconductivity has attracted great interest in condensed matter physics because of its potential applications in quantum computing. Spin-triplet superconductors are one promising class that can host the topological excitations of interest, but experimental realizations are few and far between.

### Condensed Matter Zoom Seminar | Pedram Roushan, Google | " Tuning quantum information scrambling in two-dimensional systems"

The promise of quantum computers is that certain computational tasks might be executed exponentially faster on a quantum processor than on a classical processor.

### Condensed Matter Zoom Seminar | Dmitri Efetov, ICFO | "Magic Angle Bilayer Graphene - Superconductors, Orbital Magnets, Correlated States and beyond"

When twisted close to a magic relative orientation angle near 1 degree, bilayer graphene has flat moire superlattice minibands that have emerged as a rich and highly tunable source of strong correlation physics, notably the appearance of superconductivity close to interaction-induced insulating states.

### Virtual Condensed Matter Seminar | Yuan Cao, MIT | "Competing Orders, Nematicity and Novel Josephson Effects in Superconducting Graphene Superlattices"

The emergence of two-dimensional materials have provided physicists with unprecedented way of studying the motion of electrons in a superconductor. Although superconductivity itself has been studied for more than a century, the recent advances of “twistronics” research in graphene superlattices brings fundamentally new physics into the picture...

### Condensed Matter Seminar | Alexandre Blais, Usherbrooke | "To be announced." | Joseph Henry Room

### Condensed Matter Seminar | Adrian Po, MIT | "Symmetry indicators for topological superconductors" | Joseph Henry Room, Jadwin Hall

A useful guiding principle for the search of topological superconductors is to relate the topological invariants with the behavior of the pairing order parameter on the normal-state Fermi surfaces. In this talk, we will discuss how this paradigm can be integrated with the notion of symmetry indicators, which enables an efficient diagnosis of...

### Condensed Matter Seminar | Mikhail I. Eremets, Max Planck | "Progress in high-temperature conventional superconductivity" PCTS Seminar Room 407

We studied the state of matter under extreme conditions and found new phenomena and materials, including polymeric nitrogen, transparent sodium, semimetallic hydrogen, and superconductivy in various substances.