Carrier transition is one of the major factors hindering the high-speed implementation of the Mølmer-Sørensen gates in trapped-ion quantum processors. We present an approach to design laser pulse shapes for the Mølmer-Sørensen gate in ion chains, which accounts for the effect of carrier transition on qubit-phonon dynamics. We show that the fast-oscillating carrier term effectively modifies the spin-dependent forces acting on ions, and this can be compensated by a simple nonlinear transformation of a laser pulse. Using numerical simulations for short ion chains and perturbation theory for longer chains up to 20 ions, we demonstrate that our approach allows suppression of the infidelity contribution from off-resonant carrier excitation from ${10}^{-3}$–${10}^{-2}$ to values below ${10}^{-4}$, whereas the gate duration remains of the order of tens of microseconds.

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• Light-matter interaction
• Nonlinear optics
• Pulse shaping
• Quantum computation
• Quantum gates
• Quantum information with trapped ions
• Trapped ions
• Laser techniques