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Non-Integrable Dynamics in a Trapped-Ion Quantum Simulator

June 25, 2021 - 3:00pm
Patrick Becker

Dissertation Committee Chair: Prof. Christopher Monroe


Prof. Alexey Gorshkov

Prof. Zohreh Davoudi

Prof. Chris Jarzynski

Prof. Qudsia Quraishi

Abstract:  Analog quantum simulators, specialized quantum computers limited to applying unitary evolutions instead of digitized gates, are at the forefront of controllable quantum system sizes. In place of digital algorithms, analog quantum simulators excel at studying many-body physics and modeling certain materials and transport phenomena. Here I discuss an analog quantum simulator based on trapped Yb-171 ions as well as its use for studying dynamics and thermalizing properties of the non-integrable long-range Ising model with system sizes near the limit of classical tractability.

In addition to some technical properties of the trapped-ion simulator, I present three experiments run on the machine during my PhD. The first is an observation of a phenomenon in non-equilibrium physics, a dynamical phase transition (DPT). While equilibrium phase transitions follow robust universal principles, DPTs are challenging to describe with conventional thermodynamics. We present an experimental observation and characterization of a DPT with up to 53 qubits.

We also explore the trapped-ion simulator’s ability to simulate physics beyond its own by implementing a quasiparticle confinement Hamiltonian.  Here we see that the natural long-range interactions present in the simulator induce an effective confining potential on pairs of domain-wall quasiparticles, which behave similarly to quarks bound into mesons. We measure post-quench dynamics to identify how quasiparticle confinement introduces low-energy bound states and inhibits thermalization in the system.

Lastly, we use the individual-addressing capabilities of our simulator to implement Stark many-body localization (MBL) with a linear potential gradient. Stark MBL provides a novel, disorder-free method for localizing a quantum system that would otherwise thermalize under evolution. We explore how the localized phase depends on the gradient strength and uncover the presence of correlations using interferometric double electron-electron resonance (DEER) measurements.