While Laughlin identified the fractional quantum Hall state as a consequence of an “incompressible quantum fluid”, well-described by his model  wavefunction  which exhibits “flux attachment”, no fundamental explanation of the energetics driving “flux attachment” has emerged. A new picture reveals that  a…

Studying non-abelian anyons is exciting due to their unique braiding statistics. The 5/2 quantum Hall state has been long proposed to host such localized quasiparticles in the 2D bulk. Resting on ‘bulk-edge’ correspondence, their gapless edge modes are expected to mirror the topological order of the 5/2 quantum state. Supporting an odd number…

Molecular beam epitaxy (MBE) is an epitaxial process by which we could grow single-crystal thin films, heterostructures, and superlattices with the highest achievable purity. Therefore, MBE is known as one of the most advanced and controllable material synthesis methods. In this talk, I will briefly introduce the MBE growth mechanism and then…

In 1937, Ettore Majorana suggested that a particle, which is its own antiparticle might exist. This triggered the interest of high-energy physicists, but, despite the big efforts, there is no evidence of such a particle [1]. In condensed matter, a quasiparticle with such property can be created, i.e. a Majorana zero mode (MZM). MZMs are non…

Title/Abstract TBA

Abstract: The fermion sign problem tends to stymie exploration of
highly entangled phases of fermions, such as those relevant for heavy
fermion quantum criticality. In this talk, I will present recent
progress in simulating Fermi and non-Fermi liquids in the context of
Kondo lattice systems. One of the new ideas is…

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…