Simple pulses for elimination of leakage in weakly nonlinear qubits.

By F. Motzoi, Jay M. Gambetta, Patrick Rebentrost, Frank K. Wilhelm. Physical Review Letters, 2009

731 citations recorded by the source corpus.

In realizations of quantum computing, a two-level system (qubit) is often singled out from the many levels of an anharmonic oscillator. In these cases, simple qubit control fails on short time scales because of coupling to leakage levels. We provide an easy to implement analytic formula that inhibits this leakage from any single-control analog or pixelated pulse. It is based on adding a second control that is proportional to the time derivative of the first. For realistic parameters of superconducting qubits, this strategy reduces the error by an order of magnitude relative to the state of the art, all based on smooth and feasible pulse shapes. These results show that even weak anharmonicity is sufficient and in general not a limiting factor for implementing quantum gates.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/ff61e1e29973e751d2c5760b9bbd9faa5add2705

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Citations in the corpus

High fidelity two-qubit gates on fluxoniums using a tunable coupler (2022, methodology): “[29] F Motzoi, J M Gambetta, P Rebentrost, and F K Wilhelm.”
Implementation of a Toffoli gate with superconducting circuits (2011, methodology): “We use 8-ns-long, Gaussian-shaped DRAG-pulses [24, 25] to prevent population of the third level and phase errors during the single-qubit operations.”
High-Fidelity, Frequency-Flexible Two-Qubit Fluxonium Gates with a Transmon Coupler (2023, background): “However, we also note that attempts to mitigate the effects of this undesired transition using more established pulse shaping techniques did not improve the gate fidelity [47].”
Rapid High-fidelity Multiplexed Readout of Superconducting Qubits (2018, methodology): “For all single qubit gates we used DRAG [49] shaped π-pulses with the length of 2.”
Rapid High-Fidelity Single-Shot Dispersive Readout of Superconducting Qubits (2017, methodology): “Before preparing the qubit in either the ground or excited state by applying a 18 ns R x DRAG pulse [29, 30], which ends at t = 0, we wait for about 100 ns ≈ 25/κeff for the resonator to decay back to its vacuum state after preselection.”
Training Schrödinger’s cat: quantum optimal control (2015, background): “In quantum processor candidates based on superconducting circuits, leakage to non-computational states in the most common type of qubit, the transmon [78, 260, 284], was avoided and frequency crowding was accomodated [372, 430] thanks to optimal control results.”
Quantum computing with atomic qubits and Rydberg interactions: progress and challenges (2016, methodology): “Derivative removal by adiabatic gate (DRAG) has been highly successful at solving this problem for superconducting qubits [160] and recent work has resulted in design of a Rydberg-DRAG gate with > F 0.”
Quantum Electrodynamics in a Topological Waveguide (2020, methodology): “[44] F.”
Probabilistic error cancellation with sparse Pauli–Lindblad models on noisy quantum processors (2022, methodology): “√ The single-qubit gates X and X were implemented using the standard circuit quantum electrodynamics (cQED) all-microwave-control setup, using Gaussian pulses with calibrated DRAG decoupling [43, 44], each with a total gate time of 35.5 ns (4 σ Gaussian pulses).”
Realizing repeated quantum error correction in a distance-three surface code (2021, methodology): “We realize single-qubit gates with 40-ns-duration microwave DRAG pulses [62] with a Gaussian envelope which has a standard deviation of σ = 10 ns and is truncated at ±2σ.”