Yejin Huh

Renormalization group theory of nematic ordering in d -wave superconductors

We examine the quantum theory of the spontaneous breaking of lattice rotation symmetry in d-wave superconductors on the square lattice. This is described by a field theory of an Ising nematic order parameter coupled to the gapless fermionic quasiparticles. We determine the structure of the renormalization group to all orders in a 1/N_f expansion, where N_f is the number of fermion spin components. Asymptotically exact results are obtained for the quantum critical theory in which, as in the large N_f theory, the nematic order has a large anomalous dimension, and the fermion spectral functions are highly anisotropic.

Stress tensor and current correlators of interacting conformal field theories in 2+1 dimensions: fermionic Dirac matter coupled to U(1) gauge field

We compute the central charge C T and universal conductivity C J of N F fermions coupled to a U (1) gauge field up to next-to-leading order in the 1/N F expansion. We discuss implications of these precision computations as a diagnostic for response and entanglement properties of interacting conformal field theories for strongly correlated condensed matter phases and conformal quantum electrodynamics in 2 + 1 dimensions.

Quantum criticality of the kagome antiferromagnet with Dzyaloshinskii-Moriya interactions

We investigate the zero-temperature phase diagram of the nearest-neighbor kagome antiferromagnet in the presence of Dzyaloshinksii-Moriya interaction. We develop a theory for the transition between Z2 spin liquids with bosonic spinons and a phase with antiferromagnetic long-range order. Connections to recent numerical studies and experiments are discussed.

Vector boson excitations near deconfined quantum critical points.

We show that the Néel states of two-dimensional antiferromagnets have low energy vector boson excitations in the vicinity of deconfined quantum critical points. We compute the universal damping of these excitations arising from spin-wave emission. Detection of such a vector boson will demonstrate the existence of emergent topological gauge excitations in a quantum spin system.

Optical Conductivity of Visons in Z_{2} Spin Liquids Close to a Valence Bond Solid Transition on the Kagome Lattice

For the case of transitions to a 36-site unit cell VBS state the corresponding nite ac-conductivity has a speci c power law frequency dependence, which is related to the crossoverexponent of the quantum critical point. The visons’ contribution to the optical conductivity attransitions to VBS states with a 12-site unit cell vanishes, however.I. INTRODUCTION

Optical conductivity of visons in Z 2 spin liquids close to a VBS transition on the kagome lattice

For the case of transitions to a 36-site unit cell VBS state the corresponding nite ac-conductivity has a speci c power law frequency dependence, which is related to the crossoverexponent of the quantum critical point. The visons’ contribution to the optical conductivity attransitions to VBS states with a 12-site unit cell vanishes, however.I. INTRODUCTION

Optical conductivity of visons inZ2spin liquids close to a valence bond solid transition on the kagome lattice

For the case of transitions to a 36-site unit cell VBS state the corresponding nite ac-conductivity has a speci c power law frequency dependence, which is related to the crossoverexponent of the quantum critical point. The visons’ contribution to the optical conductivity attransitions to VBS states with a 12-site unit cell vanishes, however.I. INTRODUCTION