Experimental Demonstration of Lindblad Tomography on a Superconducting Quantum Device

Information loss in experimental quantum devices is traditionally characterized using metrics such as T₁ and T₂, which are readily accessible from standard time-domain measurement. While T₁ and T₂ times provide rough heuristics for interaction between single qubits and their lossy environments, these numbers stand in as mere proxies for the full multi-qubit loss channel of interest, which can be described more fully with a Lindbladian operator in the master equation formalism. In this thesis, I outline and present the results of the first experimental demonstration of Lindblad Tomography, a novel technique for tomographically reconstructing the Hamiltonian and Lindbladian operators of an arbitrary quantum channel from an ensemble of time-domain measurements. Starting from a theoretically minimal set of assumptions, I show that this method is resilient to state-preparation and measurement (SPAM) errors and places strong bounds on the degree of non-Markovianity in the channel of interest. Comparing the results for single- and two-qubit tomography of a superconducting quantum processor, I demonstrate how Lindblad Tomography can be used to identify sources of crosstalk on large quantum processors, particularly in the presence of always-on qubit-qubit interactions.

Name thesis:degree_name

Master

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2021

Author dc:creator

• Samach, Gabriel Orr

Advisor dc:contributor.advisor

• Oliver, WIlliam D.

Statement dc:rights

• In Copyright - Educational Use Permitted
• Copyright MIT

Licence dc:rights.uri

• http://rightsstatements.org/page/InC-EDU/1.0/

Handle dc:identifier.uri

https://hdl.handle.net/1721.1/139283

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/139283