New Control Method Cuts Errors In Rydberg Qubit Entanglement

Researchers at DEVCOM Army Research Laboratory and Stevens Institute of Technology propose a new method for creating entanglement in quantum systems using modulated zero-pulse-area fields. This control protocol dynamically suppresses Rydberg excitation while maintaining the Rydberg-Rydberg interactions needed for entanglement. The work enables single-step, entangling phase gates for arbitrary blockade strengths, eliminating errors that arise when the Rabi frequency approaches or exceeds the interaction energy. The approach offers a promising route toward scalable, high-fidelity quantum computation and simulation.

Dynamic Population Suppression Enables Fast Entangling Gates

A new approach to controlling neutral-atom qubits utilizes modulated zero-pulse-area fields to achieve entanglement while dynamically suppressing unwanted Rydberg excitation. This method circumvents limitations inherent in existing protocols by dynamically managing population transfer, rather than relying on adiabatic processes or complete blockade, and proposes a versatile control protocol that retains Rydberg-Rydberg interactions as an entangling phase resource.

The core of this innovation lies in the application of two overlapping, orthogonal fields, each individually coupling to the Rydberg state, but modulated with oscillatory envelopes and a specific phase offset. This differs from traditional methods where suppressing excitation often eliminated the desired interactions, and allows for operation under resonant conditions, reducing the optical power needed and improving robustness against variations in Rydberg interaction strength.