Abstract
Conditional-phase (cz) gates in transmons can be realized by flux pulsing computational states towards resonance with noncomputational ones. We present a 40 ns cz gate based on a bipolar flux pulse suppressing leakage (0.1%) by interference and approaching the speed limit set by exchange coupling. This pulse harnesses a built-in echo to enhance fidelity (99.1%) and is robust to long-timescale distortion in the flux-control line, ensuring repeatability. Numerical simulations matching experiment show that fidelity is limited by high-frequency dephasing and leakage by short-timescale distortion.
Original language | English |
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Article number | 120502 |
Number of pages | 6 |
Journal | Physical Review Letters |
Volume | 123 |
Issue number | 12 |
DOIs | |
Publication status | Published - 2019 |
Keywords
- quantum benchmarking
- quantum control
- quantum gates
- superconducting qubits