Mitigating Optical Crosstalk for In-Situ Mid-Circuit Measurement and Reset in a Trapped-Ion Quantum Simulator
Shilpa Mahato
Trapped-ion qubits have emerged as a leading architecture for building both digital and analog quantum computers. Their long coherence times, simple state preparation and measurement procedures, and laser-based qubit manipulation make them a promising platform for quantum information processing. An important feature that can make these systems more fault-tolerant and expand their capabilities to perform different classes of simulation is high-fidelity Mid-circuit Measurement and Reset (MCMR).
Several techniques have been proposed for implementing MCMR in trapped-ion systems. Our group has taken a bold approach by relying on sophisticated optical engineering to generate a low-crosstalk individual addressing beam for performing MCMR. A Digital Micromirror Device (DMD), which is a 2D array of micro mirrors, is used to engineer an incoming wavefront to generate individual addressing beams at the ions using Fourier holography. The technique has been optimized with in-situ aberration compensation and the use of Iterative Fourier Transform Algorithm (IFTA) for hologram generation, forming the current state-of-the-art individual addressing system.
Despite these advancements, binarization effects inherent to DMD-based systems currently limit the optical intensity crosstalk to the $10^{-4}$ level, both at the nearest-neighbor qubit locations and in the asymptotic regime. To address this, we propose two optical engineering improvements to the existing holographic technique: (1) multiplexing multiple gratings, and (2) using the DMD as an intermediate optical filter to further suppress residual optical crosstalk. These enhancements to the addressing beam may contribute to higher mid-circuit measurement and reset fidelities, thereby advancing the development of a fault-tolerant quantum computing architecture.
Location
QNC 1201