- Letter
Quantum gate dynamics beyond the rotating wave approximation using multitimescale quantum averaging theory
Phys. Rev. A 113, L030403 – Published 13 March, 2026
DOI: https://doi.org/10.1103/nlvz-zrq5
Abstract
We present a quantum averaging theory (QAT) for analytically modeling unitary gate dynamics in driven quantum systems beyond the rotating wave approximation. QAT addresses the simultaneous presence of distinct timescales by generating a rotating frame with a dynamical phase operator that toggles with the high-frequency dynamics and yields an effective Hamiltonian for the slow degree of freedom. By accounting for the fast-varying effects, we demonstrate that high-fidelity two-qubit gates in strongly driven systems are achievable by going beyond the validity of first-order approximations. The QAT results rapidly converge with numerical calculations of a fast-entangling Mølmer-Sørensen trapped-ion-qubit gate in the strong-coupling regime, illustrating QAT's ability to simultaneously provide both an intuitive, effective Hamiltonian model and high accuracy.
Physics Subject Headings (PhySH)
- Coherent control
- Light-matter interaction
- Quantum computation
- Quantum control
- Quantum description of light-matter interaction
- Quantum formalism
- Quantum protocols
- Quantum simulation
- Quantum state transfer
- Spin-phonon coupling
- Stark effect
- 1-dimensional spin chains
- Ions
- Qubits
- Adiabatic approximation
- Dicke model
- Dipole approximation
- Jaynes-Cummings model
- Perturbative methods
- Rabi model
- Rotating wave approximation
- Schroedinger equation
- Two-level models
