Will Quantum Computers Scale Without Inter-Chip Comms? A Structured Design Exploration to the Monolithic vs Distributed Architectures Quest

Abstract

Being a very promising technology, with impressive advances in the recent years, it is still unclear how quantum computing will scale to satisfy the requirements of its most powerful applications. Although continued progress in the fabrication and control of qubits is required, quantum computing scalability will depend as well on a comprehensive architectural design considering a multi-core approach as an alternative to the traditional monolithic version, hence including a communications perspective. However, this goes beyond introducing mere interconnects. Rather, it implies consolidating the full communications stack in the quantum computer architecture. In this paper, we propose a double full-stack architecture encompassing quantum computation and quantum communications, which we use to address the monolithic versus multi-core question with a structured design methodology. For that, we revisit the different quantum computing layers to capture and model their essence by highlighting the open design variables and performance metrics. Using behavioral models and actual measurements from existing quantum computers, the results of simulations suggest that multicore architectures may effectively unleash the full quantum computer potential.

Scaling Superconducting Quantum Computers with Chiplet Architectures

“…The models presented here are extremely timely: modularity is gaining widespread acceptance as the best route to quantum scaling [8], [70]. In our study, we hope to guide the development of modular QCs, showing the feasibility of chiplet-based MCMs via yield, performance, and applicationbased analysis.…”

“…Studies are emerging that model linked quantum devices to better understand distributed QC performance in SC-based systems [42] and trapped-ion devices [54]. Finally, work exists that outlines architecture considerations for teleportation-based quantum multi-core systems [70] and explores latency and scaling trade-offs needed in a technology-agnostic manner for effective communication and computation in such systems [71], [72]. In this section, we describe how our contributions differ from prior art related to this study.…”

Interconnect Fabrics for Multi-Core Quantum Processors

“…Densely-packed monolithic quantum processors hosting a large number of qubits impose severe technical issues due to the effect of cross-talk, quantum state disturbance, and the increased complexity of the systems used to control the qubits [45], which deteriorates the computational results. Moreover, the interconnect between the host computer and the quantum processor (typically of extremely different form factors and placed in hugely different temperature levels) quickly becomes a bottleneck in such architectures [29,40].…”

Modeling Short-Range Microwave Networks to Scale Superconducting Quantum Computation

“…Distributed quantum architectures have been proposed in [24][25][26]. Related works present techniques for targeting a network of quantum chips for unified computing tasks [27,28].…”