Fast universal control of a flux qubit via exponentially tunable
wave-function overlap
- URL: http://arxiv.org/abs/2303.01102v2
- Date: Tue, 28 Nov 2023 11:07:36 GMT
- Title: Fast universal control of a flux qubit via exponentially tunable
wave-function overlap
- Authors: Svend Kr{\o}jer, Anders Enevold Dahl, Kasper Sangild Christensen,
Morten Kjaergaard and Karsten Flensberg
- Abstract summary: We propose a flux qubit variation which enjoys a tunable level of protection against relaxation to resolve this outstanding issue.
Our qubit design, the double-shunted flux qubit (DSFQ), realizes a generic double-well potential through its three junction ring geometry.
- Score: 0.0
- License: http://creativecommons.org/licenses/by/4.0/
- Abstract: Fast, high fidelity control and readout of protected superconducting qubits
are fundamentally challenging due to their inherent insensitivity. We propose a
flux qubit variation which enjoys a tunable level of protection against
relaxation to resolve this outstanding issue. Our qubit design, the
double-shunted flux qubit (DSFQ), realizes a generic double-well potential
through its three junction ring geometry. One of the junctions is tunable,
making it possible to control the barrier height and thus the level of
protection. We analyze single- and two-qubit gate operations that rely on
lowering the barrier. We show that this is a viable method that results in high
fidelity gates as the non-computational states are not occupied during
operations. Further, we show how the effective coupling to a readout resonator
can be controlled by adjusting the externally applied flux while the DSFQ is
protected from decaying into the readout resonator. Finally, we also study a
double-loop gradiometric version of the DSFQ which is exponentially insensitive
to variations in the global magnetic field, even when the loop areas are
non-identical.
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