Analytical blueprint for 99.999% fidelity X-gates on present superconducting hardware under strong driving

arXiv (Cornell University)

Abstract

Achieving very fast gates that undercut the natural limits set by decoherence requires going into the strong driving limit. Realizing single-qubit control predicted beyond semi-classical, time-dependent modeling has yet to be experimentally realized on superconducting and most other computing platforms. In this regime, the common model of dynamics within a three-level manifold breaks down, and instead, we see new quantum error channels growing abruptly with decreasing time. To identify these error processes we systematically calculate the effect of multi-photon transitions that occur out of the computational space. We then derive analytical formulas to suppress these effects, as well as amplitude and phase errors on the qubit space; we term these R1D for suppressing the $|0\rangle-|2\rangle$ transition and R2D when also suppressing $|1\rangle-|3\rangle$ leakage. We also answer long-standing questions about the optimal values of the DRAG prefactor as well as constant detuning, when accounting for time-ordering, and also show how to calibrate other prefactors for further performance improvement. Upon correcting these varied sources of error, we numerically demonstrate gate infidelities below $10^{-5}$ for a 7ns $π$-rotation when incorporating existing decoherence rates.

Authors 6

1. José Diogo Da Costa Jesus
2. Boxi Li

   Forschungszentrum Jülich

   Affiliation as printed

   Institute for Quantum Control (PGI-8) , Forschungszentrum Jülich , 52425 Jülich , Germany

3. Yuan Gao Aachen Department of Physics

   RWTH Aachen University · Forschungszentrum Jülich

   Affiliation as printed

   Department of Physics , RWTH Aachen University , 52074 Aachen , Germany

   Institute for Functional Quantum System (PGI-13) , Forschungszentrum Jülich , 52425 Jülich , Germany

4. Rami Barends Aachen Department of Physics

   RWTH Aachen University · Forschungszentrum Jülich

   Affiliation as printed

   Department of Physics , RWTH Aachen University , 52074 Aachen , Germany

   Institute for Functional Quantum System (PGI-13) , Forschungszentrum Jülich , 52425 Jülich , Germany

5. F. A. Cárdenas-López

   Forschungszentrum Jülich

   Affiliation as printed

   Institute for Quantum Control (PGI-8) , Forschungszentrum Jülich , 52425 Jülich , Germany

6. Felix Motzoi

   Forschungszentrum Jülich · University of Cologne

   Affiliation as printed

   Institute for Quantum Control (PGI-8) , Forschungszentrum Jülich , 52425 Jülich , Germany

   Institute for Theoretical Physics , University of Cologne , 50937 Cologne , Germany