Dynamically Generated Decoherence-Free Subspaces and Subsystems in Superconducting Qubits

RQS Career Connections

Gregory D. Quiroz (Johns Hopkins University)
Friday, February 2, 2024 - 11:00am
ATL 3100A and Virtual Via Zoom

11am - 11:30 am: Research Talk

11:30 am - 12:30 pm: Career Talk

Decoherence-free subspaces (DFS) are error-avoiding quantum codes that preserve quantum information by encoding it into symmetry-protected states unaffected by decoherence. An inherent DFS of a given experimental system may not exist; however, through the use of dynamical decoupling (DD), one can induce symmetries that generate effective DFSs. Here, we provide the first demonstration of DD-generated DFS logical qubits. Utilizing the IBM superconducting qubits Quantum Platform, we investigate two and three-qubit DFS codes on up to six and seven logical qubits, respectively. Through a combination of DD and error detection, we show that DFS logical qubits can achieve up to a 23% improvement in qubit fidelity over physical qubits subject to DD alone. This constitutes a beyond-breakeven fidelity improvement for DFS-encoded qubits. Our results showcase the potential utility of DFS codes as a pathway towards enhanced computational accuracy via logical encoding on quantum processors.

Bio: Dr. Gregory Quiroz is a senior scientist at the Johns Hopkins University Applied Physics Laboratory. In addition, he holds an adjunct professor position in the Physics and Astronomy Department at Johns Hopkins University. Dr. Quiroz received his PhD from the University of Southern California in 2013, where he studied quantum control and adiabatic quantum computation. Thereafter, he transitioned to a role as a staff scientist at the Aerospace Corporation in Los Angeles, CA. His research focused on quantum communication and quantum algorithm development for National Security Space applications. Since 2016, he has been a senior scientist at the Johns Hopkins University Applied Physics Laboratory, where he now also holds the role of supervisor for the Quantum Exploitation section within the R&D sector of the lab. His current research interests include quantum characterization and control, applications of quantum control to quantum algorithm design, and quantum sensing.

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