Quantum Simulation of Many-body Systems with Superconducting Qubits

Abstract

The study of interacting many-body quantum systems is central to the understanding of wide a range of physical phenomena in condensed-matter systems, quantum gravity, and quantum circuits. However, quantum systems are often hard to study analytically, and the classical computing resources required for simulating them scale exponentially with the size of the system. In this thesis, we discuss utilizing superconducting quantum circuits as a wellcontrolled quantum platform for probing the out-of-equilibrium dynamics and the properties of many-body quantum systems. We use a 3×3 array of superconducting transmon qubits to study the dynamics of a particle under the tight-binding model, and probe quantum information propagation by measuring out-of-time-ordered correlators (OTOCs). Using a 4×4 qubit array, we probe entanglement across the energy spectrum of a hard-core Bose-Hubbard lattice by extracting correlation lengths and entanglement entropy of superposition states generated in particular regions of the spectrum, from the band center to its edge. The results presented in this thesis are in close quantitative agreement with numerical simulations. The demonstrated level of experimental control and accuracy in extracting the system observables of interest is extensible to larger superconducting quantum simulators and will enable the exploration of larger, non-integrable systems where numerical simulations become intractable.