Bulletin of the American Physical Society
Optical lattice-based addressing and control of long-lived neutral-atom qubits
Nathan E. Lundblad, Trey Porto, Ian B. Spielman, Radu Chicireanu, William D. Phillips
Abstract
The design of many proposed quantum computational platforms is driven by competing needs: isolating the quantum system from the environment to prevent decoherence, and easily and accurately controlling the system with external fields. Neutral-atom optical-lattice architectures provide environmental isolation through the use of states that are robust against fluctuating external fields, yet external fields are nevertheless essential for qubit addressing. Here we demonstrate the selection of individual qubits with external fields, despite the fact that the qubits are in field-insensitive superpositions. We use a spatially inhomogeneous external field to map selected qubits to a different field-insensitive superposition, minimally perturbing unselected qubits, despite the fact that the addressing field is not spatially localized. We show robust single-qubit rotations on neutral-atom qubits located at sites within a double-well configuration with minimal dephasing of neighboring qubits. This precise coherent control is an important step forward for lattice-based neutral-atom quantum computation, and is quite generally applicable to state transfer and qubit isolation in other architectures using field-insensitive qubits. Additionally this double-well proof-of-principle work should be quite applicable in the single-site addressability regime currently being explored by several groups. Additionally we present work demonstrating the near-elimination of the differential light shift for various qubit transitions, using a novel scheme balancing differential shifts with residual vector light shifts of nominally field-insensitive transitions. For details see references [1–6]