A Fast 7Li-based Quantum Simulator

Abstract

The work presented in this thesis is the design and characterization of a new apparatus for quantum simulation using bosonic Lithium in optical lattices, along with proposals for simulations of the spin-1 Heisenberg model and the results of initial exploratory experiments. The topic itself falls under the general category of adiabatic analog quantum computing with neutral atoms: a physical instantiation of a simple quantum mechanical Hamiltonian is built out of 7Li atoms near zero temperature and results are measured directly from the model system. While the techniques employed in this work are inspired by progress and discoveries in atomic physics, its applications are to the study of condensed matter systems, and similar approaches may one day be used to address a wider range of computational problems. The strategy of adiabatic analog quantum computing comprises evolving the system through a chain of different ground states until the desired state is reached, and the structure of this thesis reflects that progression. Chapter 1 situates this work in the context of the larger effort to build computational devices, and introduces the approach followed in this work. Chapter 2 documents the design and construction of the apparatus for cooling 7Li to quantum degeneracy, with emphasis on the apparatus’ unique features, including fast evaporative cooling and tunable magnetic bias fields with low curvature. Chapter 3 discusses the role and implementation of the optical lattice, as well as continuing efforts to characterize and mitigate decoherence mechanisms. Finally, Chapter 4 reports the results of a new lattice-based spectroscopic method for determining the strength of atomic contact interactions and further suggests how these results can be used to perform a simulation of the spin-1 Heisenberg model.