Fractional quantum Hall (FQH) states are topologically ordered. Additionally, FQH states support a collective neutral excitation known as the Girvin-MacDonald-Platzman (GMP) mode. Certain features of this mode are independent of the microscopic details. The objective of the talk is to construct an effective theory includes both topological…

Abstract:  We present recent advances in our understanding of (i) exotic quantum phases of matter in three dimensions, and (ii) robust mechanisms for storing and processing quantum information, that have been enabled by new techniques to study highly-entangled quantum states.  First, we introduce  new kinds of gapped quantum phases in three…

When the twist angle of a bilayer graphene is commensurate and near the `magic' value, there are four narrow bands near the neutrality point, each two-fold spin degenerate. These bands are separated from the rest of the bands by energy gaps.

In the first part of the talk, the method for microscopic construction of symmetry adapted…

Superconducting circuits have emerged as a competitive platform for quantum computation, satisfying the challenges of controllability, long coherence and strong interactions. Here we apply this toolbox to a different problem: the exploration of strongly correlated quantum materials made of microwave photons. We develop a versatile recipe that…

Abstract: A recent experiment in the Rydberg atom chain observed unusual oscillatory quench dynamics with a charge density wave initial state, and theoretical works identified a set of many-body ``scar states'' in the Hamiltonian as potentially responsible for the atypical dynamics. In the same nonintegrable…

Searching for a proper set of order parameters which distinguish different phases of matter sits in the heart of condensed matter physics. In this talk, I discuss topological invariants as (non-local) order parameters of symmetry protected topological (SPT) phases of fermions in the presence of anti-unitary symmetries. I introduce a general…

Physical systems differing in their microscopic details often display strikingly similar behaviour when probed at macroscopic scales. Those universal properties, largely determining their physical characteristics, are revealed by the renormalization group (RG) procedure, which systematically retains ‘slow’ degrees of freedom and integrates out…

A convergent summation formula for the DC Hall number of strongly correlated and disordered metals is derived from the Kubo formula. Properties of Bogoliubov operator Hilbert space are used for the derivation [1]. The Hall number (remarkably) generally depends solely on equilibrium thermodynamic susceptibilities,…

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Off-resonant optical coupling of an atomic ground state to a Rydberg state, so-called "Rydberg-dressing", has been proposed as a versatile method to implement various long-range interacting spin models with ultracold atoms.
 

In our experiment, we…

Abstract:  We have found that the strong spin Hall effect in TaAs is mainly dominated from the Weyl points and nodal-line-like Fermi surface, which implying a strong interplay between the topological band structure and Berry curvature in topological semimetals. With this guiding principle, we have successfully understood the strong spin Hall…

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Spin qubits in dilute nuclear-spin materials such as silicon and carbon are currently among the most coherent systems for quantum information processing.

Yet, while the small magnetic moment associated with electron spins provides excellent shielding of the…

Abstract:  It is well known that conserved quantities cannot have anomalous dimensions.  However, a recent proposal for the ubiquitous strange metal phase in the cuprates argues just the opposite.  Namely,  all of the properties of such `strange metals' can be understood if the current has an anomalous dimension.   My talk will focus on trying…

Abstract:  Impurity physics has emerged as a new branch of research in the field of atomic quantum gases. A central feature is the wide tunability of interactions between the impurities and the surrounding medium. By using magnetically controlled Feshbach resonances, regimes of strong interactions can be reached which reveal intriguing many…

Abstract:  Isolated quantum many-body systems with integrable dynamics generically do not thermalize starting from generic initial states when taken far from equilibrium.  As one perturbs such systems away from the integrable point, thermalization sets in, but the nature of the crossover from integrable to thermalizing behavior is an unresolved…

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: The study of the magnetic-field driven superconductor-insulator transition in thin superconducting films at low temperatures reveals an unusual insulator whose conductivity seems to approach zero at a finite temperature, while its current-voltage characteristics are bistable, indicating that…

Abstract:  Ground states of gapped Hamiltonians can form 'symmetry-protected topological phases', characterized by zero-energy edge modes. We explore the quantum critical points between such topological phases in one spatial dimension. Two main questions are addressed, namely how universal properties of the critical point are related to the…

Abstract:  Artificial Intelligence/Machine learning has seen large growth and a number of successes over the past few years. In this talk I will describe some of the core ideas and algorithms along with corresponding results. We will start by thinking about intelligence in general. This will lead us to the problem of perception, where I will…

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The Kitaev model on a honeycomb lattice predicts a special quantum spin liquid (QSL) ground state with excitations resembling Majorana Fermions and gauge flux excitations. These emergent features are exciting prospects to both basic physics and applications towards a lossless technology for…

Abstract:  This talk will present our on-going effort to control the dipole-dipole interaction between cold Rydberg atoms in order to implement spin Hamiltonians that may be useful for quantum simulation of condensed matter problems. In our experiment, we trap individual atoms in two-dimensional arrays of optical tweezers [