Origin of bulk two-level system loss in superconducting circuits on silicon: Part II Theory
ORAL
Abstract
Two-level systems (TLS) in amorphous materials are the dominant loss mechanism for superconducting quantum circuits. While the microscopic origin of amorphous TLSs is still unknown, recent efforts enabled reduction in interface TLS losses via reduced surface participation and improved surface treatment. With these improvements, experiments are now approaching a regime where bulk TLS losses may have a significant contribution to qubit loss. In this work, we present the first microscopic identification of a TLS bath for superconducting circuits based on defects in bulk silicon. We use low surface-participation microwave resonators to study the impact of common acceptors and donors on microwave losses. We show that spin-orbit acceptor systems lead to a large microwave loss tangent at the single-photon level. In this talk, we describe a microscopic model to explain the experimental observations. We discuss the impact of these observations for low-loss superconducting circuits on silicon, and the prospect of using acceptor spins for building hybrid quantum systems in silicon.
*This work is supported by AFOSR and DOE.
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Presenters
Kadircan Godeneli
University of California, Berkeley and Lawrence Berkeley National Laboratory, University of California, Berkeley
Authors
Kadircan Godeneli
University of California, Berkeley and Lawrence Berkeley National Laboratory, University of California, Berkeley
Zihuai Zhang
University of California, Berkeley and Lawrence Berkeley National Laboratory, Princeton University, University of California, Berkeley, University of California, Berkeley; Lawrence Berkeley National Laboratory
Srujan Meesala
Caltech
Alp Sipahigil
University of California, Berkeley and Lawrence Berkeley National Laboratory, University of California, Berkeley, University of California, Berkeley; Lawrence Berkeley National Laboratory
