Demonstration of quantum advantage by a joint detection receiver for optical communications using quantum belief propagation on a trapped-ion device

Abstract

Demonstrations of quantum advantage have largely focused on computational speedups and on quantum simulation of many-body physics, limited by fidelity and capability of current devices. Discriminating laser-pulse-modulated classical-communication codewords at the minimum allowable probability of error using universal-quantum processing presents a promising parallel direction, one that is of both fundamental importance in quantum state discrimination, as well as of technological relevance in deep-space laser communications. Here we present an experimental realization of a quantum joint detection receiver for binary phase shift keying modulated codewords of a 3-bit linear tree code using a recently-proposed quantum algorithm: belief propagation with quantum messages. The receiver, translated to a quantum circuit, was experimentally implemented on a trapped-ion device -- the recently released Honeywell LT-1.0 system using ${}^{171}Yb+$ ions, which possesses all-to-all connectivity and mid-circuit measurement capabilities that are essential to this demonstration. We conclusively realize a previously postulated but hitherto not-demonstrated joint quantum detection scheme, and provide an experimental framework that surpasses the quantum limit on the minimum average decoding error probability associated with pulse-by-pulse detection in the low mean photon number limit. The full joint-detection scheme bridges across photonic and trapped-ion based quantum information science, mapping the photonic coherent states of the modulation alphabet onto inner product-preserving states of single-ion qubits. Looking ahead, our work opens new avenues in hybrid realizations of quantum-enhanced receivers with applications in astronomy and emerging space-based platforms.

arXiv comment15 pages

References in corpus (25)

• An Open-System Quantum Simulator with Trapped Ions
• Multi-particle entanglement of hot trapped ions
• Advances in Quantum Teleportation
• Demonstration of a small programmable quantum computer with atomic qubits
• Large Scale Modular Quantum Computer Architecture with Atomic Memory and Photonic Interconnects
• Demonstration of the trapped-ion quantum-CCD computer architecture
• Benchmarking an 11-qubit quantum computer
• Realization of a scalable Shor algorithm
• Efficient long distance quantum communication
• Classical capacity of the lossy bosonic channel: the exact solution
• Modular Entanglement of Atomic Qubits using both Photons and Phonons
• Ultrafast and Fault-Tolerant Quantum Communication across Long Distances
• Ultimate communication capacity of quantum optical channels by solving the Gaussian minimum-entropy conjecture
• Structured optical receivers to attain superadditive capacity and the Holevo limit
• Polar codes for classical-quantum channels
• Optical codeword demodulation with error rates below standard quantum limit using a conditional nulling receiver
• PPM demodulation: On approaching fundamental limits of optical communications
• Capacity of optical communication in loss and noise with general Gaussian receivers
• Realizable receivers for discriminating arbitrary coherent-state waveforms and multi-copy quantum states near the quantum limit
• Achieving minimum-error discrimination of an arbitrary set of laser-light pulses
• On quantum limit of optical communications: concatenated codes and joint-detection receivers
• Belief Propagation with Quantum Messages for Quantum-Enhanced Classical Communications
• Near optimal discrimination of binary coherent signals via atom-light interaction
• Belief propagation decoding of quantum channels by passing quantum messages
• Superadditivity of Quantum Channel Coding Rate with Finite Blocklength Joint Measurements

Cited by in corpus (6)

• Discriminating mixed qubit states with collective measurements
• Superadditive Communication with the Green Machine: A Practical Demonstration of Nonlocality without Entanglement
• Quantum computer-enabled receivers for optical communication
• Transceiver designs to attain the entanglement assisted communications capacity
• Attainability of quantum state discrimination bounds with collective measurements on finite copies
• Quantum-Processing-Assisted Classical Communications