Robust Majorana magic gates via measurements
Abstract
π/8 phase gates (magic gates or T gates) are crucial to augment topological systems based on Majorana zero modes to full quantum universality. We present a scheme based on a combination of projective measurements and nonadiabatic evolution that effectively cancels smooth control errors when implementing phase gates in Majorana-based systems. Previous schemes based on adiabatic evolution are susceptible to problems arising from small but finite dynamical phases that are generically present in topologically unprotected gates. A measurement-only approach eliminates dynamical phases. For nonprotected gates, however, forced-measurement schemes are no longer effective, which leads to low success probabilities of obtaining the right succession of measurement outcomes in a measurement-only implementation. We show how to obtain a viable measurement-based scheme which dramatically increases the success probabilities by evolving the system nonadiabatically with respect to the degenerate subspace in between measurements. We outline practical applications of our scheme in recently proposed quantum computing designs based on Majorana tetrons and hexons.
Additional Information
© 2019 American Physical Society. (Received 12 February 2019; revised manuscript received 4 April 2019; published 24 April 2019) We acknowledge useful discussions with Christina Knapp and Parsa Bonderson. We are grateful for the hospitality of the Aspen Center for Physics, where part of this work was performed. GR is grateful for support from the Institute of Quantum Information and Matter, an NSF frontier center. YO acknowledges the European Research Council under the European Union's Seventh Framework Program (FP7/2007-2013)/ERC Project MUNATOP, the DFG (CRC/Transregio 183, EI 519/7-1), and the Israel Science Foundation and the United States - Israel Binational Science Foundation.Attached Files
Published - PhysRevB.99.144521.pdf
Accepted Version - 1812.10498.pdf
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Additional details
- Eprint ID
- 94942
- Resolver ID
- CaltechAUTHORS:20190424-142039996
- Institute for Quantum Information and Matter (IQIM)
- NSF
- European Research Council (ERC)
- MUNATOP
- Deutsche Forschungsgemeinschaft (DFG)
- EI 519/7-1
- Israel Science Foundation
- Binational Science Foundation (USA-Israel)
- Created
-
2019-04-24Created from EPrint's datestamp field
- Updated
-
2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Walter Burke Institute for Theoretical Physics, Institute for Quantum Information and Matter