Andrew James

Understanding the entanglement entropy and spectra of 2D quantum systems through arrays of coupled 1D chains

We describe an algorithm for studying the entanglement entropy and spectrum of two-dimensional (2D) systems, as a coupled array of N one-dimensional chains in their continuum limit. Using the algorithm to study the quantum Ising model in 2D (both in its disordered phase and near criticality), we confirm the existence of an area law for the entanglement entropy and show that near criticality there is an additive piece scaling as c eff log(N)/6 with c eff ≈1. Studying the entanglement spectrum, we show that entanglement gap scaling can be used to detect the critical point of the 2D model. When short-range (area law) entanglement dominates we find (numerically and perturbatively) that this spectrum reflects the energy spectrum of a single quantum Ising chain.

Finite-temperature dynamical structure factor of alternating Heisenberg chains

We develop a low-temperature expansion for the finite temperature dynamical structure factor of the spin half Heisenberg chain with alternating nearest neighbour exchange in the limit of strong alternation of the exchange constants. We determine both the broadening of the low lying triplet lines and the contribution of the thermally activated intraband scattering.

Spin dynamics of the quasi-two-dimensional spin- 1 2 quantum magnet Cs 2 CuCl 4

We study dynamical properties of the anisotropic triangular quantum antiferromagnet

Auxiliary fermion approach to the resonant inelastic x-ray scattering response in an underdoped cuprate

{\mathrm{Cs}}_{2}{\mathrm{CuCl}}_{4}

Signatures of rare states and thermalization in a theory with confinement.

. Inelastic neutron scattering measurements have established that the dynamical spin correlations cannot be understood within a linear spin wave analysis. We go beyond linear spin wave theory by taking interactions between magnons into account in a

Combining integrability and MPS methods to study the two-dimensional Heisenberg model

1∕S

Time-Dependent Behavior in Arrays of Coupled Heisenberg Spin Chains

expansion. We determine the dynamical structure factor and carry out extensive comparisons with experimental data. We find that compared to linear spin wave theory, a significant fraction of the scattering intensity is shifted to higher energies and strong scattering continua are present. However, the

Quantum Quenches in Arrays of Coupled Luttinger Liquids

1∕S

Quantum quenches in 2D via arrays of coupled chains

expansion fails to account for the experimentally observed large quantum renormalization of the exchange energies.

Spin dynamics of the quasi-two-dimensional spin-12 quantum magnet Cs2CuCl4

Yifei Shi, Andrew J. A. James, Eugene Demler and Israel Klich 1 Department of Physics, University of Virginia, Charlottesville, VA 22904, USA 2 Department of Chemistry, McGill University, Montréal, Québec H3A 0B8, Canada 3 London Centre for Nanotechnology, University College London, Gordon Street, London WC1H 0AH, United Kingdom 4 Physics Department, Harvard University, Cambridge, Massachusetts 02138, USA