Simulating quantum spin models using Rydberg-excited atomic ensembles in magnetic microtrap arrays

In collaboration with Prof. Peter Hannaford (Swinburne, Australia) and Dr. Alexander Glaetzle (IQOQI, Innsbruck, Austria, and Oxford, UK), we proposed a scheme to simulate lattice spin models based on strong, long-range interacting Rydberg atoms stored in a large-spacing array of magnetic microtraps.

Periodic arrays of quantum spins coupled through magnetic interactions represent an archetypal model system in quantum many-body physics, non-equilibrium physics, statistical physics and condensed matter physics, with potential implications ranging from quantum magnetism to quantum information science, spintronics and high-temperature superconductivity. Apart from a few special cases, such models are generally computationally intractable due to extreme complexity arising from quantum entanglement between the spins. Furthermore, experimental studies on solid-state spin systems are often restricted by uncontrolled disorder and random couplings to the environment as well as limited control over system parameters. In our proposal, each spin is encoded in a collective spin state involving a single nS or (n+1)S Rydberg atom excited from an ensemble of ground-state alkali atoms prepared via Rydberg blockade. After the excitation laser is switched off, the Rydberg spin states on neighbouring lattice sites interact via general XXZ spin–spin interactions. To read out the collective spin states we propose a single Rydberg atom triggered avalanche scheme in which the presence of a single Rydberg atom conditionally transfers a large number of ground-state atoms in the trap to an untrapped state which can be readily detected by site-resolved absorption imaging. Such a quantum simulator should allow the study of quantum spin systems in almost arbitrary one-dimensional and two-dimensional configurations. This paves the way towards engineering exotic spin models, such as spin models based on triangular-symmetry lattices which can give rise to frustrated-spin magnetism.

Journal of Physics B: Atomic, Molecular and Optical Physics 50, 074001