Analytic leakage suppression with a single control field: fast two-qubit gates with tunable couplers
Abstract
Simple analytic pulse-shaping techniques are of great practical utility in quantum control, with prime examples being the DRAG method for suppressing leakage in superconducting microwave gates and the transitionless-driving approach to shortcuts-to-adiabaticity. Standard versions of these methods require two orthogonal control channels, with the second channel effectively breaking time-reversal symmetry. This appears to rule out their use in settings with only a single real-valued control field, such as the kind of baseband flux control that is common in many superconducting circuit architectures. We show here that a simple analytic pulse-shaping technique derived via a Magnus expansion is effective even with just a single baseband control channel. We demonstrate its efficacy by simulating a two-qubit gate between transmons realized with a tunable coupler and baseband flux pulses. Our corrections dramatically reduce non-adiabatic leakage caused by ramping the coupler: for realistic device parameters, leakage in a fast iSWAP gate is suppressed by up to three orders of magnitude. Our approach is general, goes beyond simply suppressing unwanted spectral weight at leakage transitions, and can be applied to a variety of platforms.
Related
- Geodesic-based optimal control for leakage suppression in superconducting qubits
- Fast CZ gate in hybrid fluxonium-transmon systems with tunable couplers
- A Novel q-Derivative Framework with Applications to q-Deformed Thermodynamics and Leakage Suppression in Superconducting Qubits
- Half-Integer Spectral Zeros for Leakage Suppression in Fast Transmon Pulses
- Higher-Order Magnus Corrections to Leakage Elimination Operator-Based Quantum Control Pulse Design in the Low-Frequency Regime
BibTeX
@misc{heunisch2026analytic,
title = {{Analytic leakage suppression with a single control field: fast two-qubit gates with tunable couplers}},
author = {Lukas Heunisch and Michael J. Hartmann and Aashish A. Clerk},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.20766},
eprint = {2609.20766},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.20766},
}
RIS
TY - UNPB
TI - Analytic leakage suppression with a single control field: fast two-qubit gates with tunable couplers
AU - Lukas Heunisch
AU - Michael J. Hartmann
AU - Aashish A. Clerk
PY - 2026
DA - 2026/09/17
PB - arXiv
DO - 10.48550/arxiv.2609.20766
UR - https://arxiv.org/abs/2609.20766
AB - Simple analytic pulse-shaping techniques are of great practical utility in quantum control, with prime examples being the DRAG method for suppressing leakage in superconducting microwave gates and the transitionless-driving approach to shortcuts-to-adiabaticity. Standard versions of these methods require two orthogonal control channels, with the second channel effectively breaking time-reversal symmetry. This appears to rule out their use in settings with only a single real-valued control field, such as the kind of baseband flux control that is common in many superconducting circuit architectures. We show here that a simple analytic pulse-shaping technique derived via a Magnus expansion is effective even with just a single baseband control channel. We demonstrate its efficacy by simulating a two-qubit gate between transmons realized with a tunable coupler and baseband flux pulses. Our corrections dramatically reduce non-adiabatic leakage caused by ramping the coupler: for realistic device parameters, leakage in a fast iSWAP gate is suppressed by up to three orders of magnitude. Our approach is general, goes beyond simply suppressing unwanted spectral weight at leakage transitions, and can be applied to a variety of platforms.
ER -