Quantum-enhanced reconfigurable in-memory stochastic computing.

In-memory computing, which enables computation directly within memory, represents an efficient approach to processing massively parallel computation tasks that are intractable for conventional computers. However, implementations of in-memory computing have been primarily limited to the classical regime, with its nonclassical counterpart yet to be fully explored. Quantum memory, with its unique capability to generate, preserve, and nontrivially operate on quantum states, offers spectacular quantum-enhanced advantages and is thus a promising candidate for in-memory computing. Here, leveraging a room-temperature quantum memory, we demonstrate a quantum-enhanced and reconfigurable in-memory stochastic computing system, where correlated photons, randomly produced in the quantum memory, serve as the computing resources. We show that addition and multiplication operations can be straightforwardly achieved by accumulating photon counts, and multiple computing tasks can be accelerated by mapping them into parallel accumulations of photon counts. Furthermore, the calculation results are obtained through stochastic processes, ensuring security in remote computation since no efficient information can be distinguished by eavesdropping on a small portion of the computation data. This in-memory computing system is enhanced by nonclassical correlations, which accelerate computing process and may stimulate future research and applications in the emerging field of quantum-enhanced computing architectures.