Dynamical Decoupling and Dephasing in Interacting Two-Level Systems

We implement dynamical decoupling techniques to mitigate noise and enhance the lifetime of an entangled state that is formed in a superconducting flux qubit coupled to a microscopic two-level system. By rapidly changing the qubit’s transition frequency relative to the two-level system, we realize a...

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Bibliographic Details
Main Authors: Bylander, Jonas, Gustavsson, Simon, Oliver, William D., Orlando, Terry Philip, Yan, Fei, Nakamura, Yasunobu, Yoshihara, Fumiki
Other Authors: Lincoln Laboratory
Format: Article
Language:en_US
Published: American Physical Society 2012
Online Access:http://hdl.handle.net/1721.1/72208
https://orcid.org/0000-0002-7069-1025
https://orcid.org/0000-0002-4674-2806
https://orcid.org/0000-0002-4436-6886
Description
Summary:We implement dynamical decoupling techniques to mitigate noise and enhance the lifetime of an entangled state that is formed in a superconducting flux qubit coupled to a microscopic two-level system. By rapidly changing the qubit’s transition frequency relative to the two-level system, we realize a refocusing pulse that reduces dephasing due to fluctuations in the transition frequencies, thereby improving the coherence time of the entangled state. The coupling coherence is further enhanced when applying multiple refocusing pulses, in agreement with our 1/f noise model. The results are applicable to any two-qubit system with transverse coupling and they highlight the potential of decoupling techniques for improving two-qubit gate fidelities, an essential prerequisite for implementing fault-tolerant quantum computing.