Sensitivity to Imperfections of Analog Quantum Simulation on Atomic Qudits

As uncorrected quantum processors grow in sophistication, many are being used for analog quantum simulation (AQS) of novel physics beyond the capabilities of classical devices. However, without the guarantee of bounded errors achieved by digitizing the computation, we do not know when and how much to trust an AQS result in the presence of inevitable imperfections. Here, we present the results of using our exper- iment as a testbed for studying the impact of errors on AQS. We have developed a small but highly-accurate processor over a 16-dimensional Hilbert space comprising the combined electron-nuclear spin of a single 133Cs atom in the electronic ground state. Advances in Eigenvalue-Only (EVO) optimal control enable us to repeatedly (>100) perform arbitrary unitary transformations in this space while maintaining accuracy on the device. We use this capability to simulate model systems known to exhibit features of interest, such as chaos and hypersensitivity (quantum kicked top) and quantum phase transitions (the transverse Ising and Lipkin-Meshkov-Glick mod- els). Experimental simulations show high fidelity of the quantum state and dynamical features in the presence of native imperfections. We discuss these results in the con- text of a new framework for quantifying the average sensitivity of simulator outcomes to errors. These theoretical and experimental results support the idea that AQS of ‘macroscopic’ observables (e.g., total magnetization) can be robust in the presence of errors, while observables tied to a specific quantum state (e.g., the fidelity) are not.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Graduate College

Grantor dc:publisher

The University of Arizona.

Year dc:date.issued

2020

Author dc:creator

• Lysne, Nathan Kenneth

Advisor dc:contributor.advisor

• Jessen, Poul S.

Committee members dc:contributor.committeemember

• Visscher, Koen
• Anderson, Brian P.
• Sandhu, Arvinder
• Wilson, Dalziel

• analog quantum simulation
• optimal control

Statement dc:rights

• Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction, presentation (such as public display or performance) of protected items is prohibited except with permission of the author.

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10150/648644

OAI identifier oai:identifier

oai:repository.arizona.edu:10150/648644