title: High-Fidelity Single-Shot Toffoli Gate via Quantum Control.
abstract: A single-shot Toffoli, or controlled-controlled-not, gate is desirable for classical and quantum information processing. The Toffoli gate alone is universal for reversible computing and, accompanied by the Hadamard gate, forms a universal gate set for quantum computing. The Toffoli gate is also a key ingredient for (nontopological) quantum error correction. Currently Toffoli gates are achieved by decomposing into sequentially implemented single- and two-qubit gates, which require much longer times and yields lower overall fidelities compared to a single-shot implementation. We develop a quantum-control procedure to construct a single-shot Toffoli gate for three nearest-neighbor-coupled superconducting transmon systems such that the fidelity is 99.9% and is as fast as an entangling two-qubit gate under the same realistic conditions. The gate is achieved by a nongreedy quantum control procedure using our enhanced version of the differential evolution algorithm.
authors.affiliation: Institute for Quantum Science and Technology, University of Calgary, Alberta, Canada T2N 1N4.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Zahedinejad
authors.affiliation: Institute for Quantum Science and Technology, University of Calgary, Alberta, Canada T2N 1N4.
authors.forename: Joydip
authors.initials: J
authors.lastname: Ghosh
authors.affiliation: Institute for Quantum Science and Technology, University of Calgary, Alberta, Canada T2N 1N4.|Program in Quantum Information Science, Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada.|Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Anhui 230026, China.|Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China.
authors.forename: Barry C
authors.initials: BC
authors.lastname: Sanders