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IQIM Postdoctoral and Graduate Student Seminar

Friday, March 24, 2023
12:00pm to 1:00pm
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East Bridge 114
Erasure qubits: Overcoming the T1 limit in superconducting circuits
Arbel Haim, AWS Center for Quantum Computing,

Abstract: The amplitude damping time, T_1, has long stood as the major factor limiting quantum fidelity in superconducting circuits, prompting concerted efforts in the material science and design of qubits aimed at increasing T_1. In contrast, the dephasing time, T_\phi, can usually be extended above T_1 (via, e.g., dynamical decoupling), to the point where it does not limit fidelity. In this article we propose a scheme for overcoming the conventional T_1 limit on fidelity by designing qubits in a way that amplitude damping errors can be detected and converted into erasure errors. Compared to standard qubit implementations our scheme improves the performance of fault-tolerant protocols, as numerically demonstrated by the circuit-noise simulations of the surface code. We describe two simple qubit implementations with superconducting circuits and discuss procedures for detecting amplitude damping errors, performing entangling gates, and extending T_\phi. Our results suggest that engineering efforts should focus on improving T_\phi and the quality of quantum coherent control, as they effectively become the limiting factor on the performance of fault-tolerant protocols.


Lunch will be provided, following the talk, on the lawn north of the Bridge Arcade

Attendees joining in person must demonstrate that they comply with Caltech's vaccination requirements (present Caltech ID or AWS ID or vaccination and booster confirmation).

For more information, please contact Marcia Brown by phone at 626-395-4013 or by email at [email protected].