Fault-tolerant quantum computing with photonics

Mercedes Gimeno-Segovia, Hugo V. Cable

Maike Ostmann, Joshua Nunn, Alex E. Jones

We propose a novel architecture for fault-tolerant quantum computing that incorporates strong single-photon nonlinearities into a photonic GHZ-measurement-based architecture. The nonlinearities substantially reduce resource overheads compared to conventional linear-optics-based architectures, which require significant redundancy to accommodate probabilistic photon generation and probabilistic entangling operations. By removing linear-optical failure modes, our nonlinear architecture can also tolerate much higher optical losses than linear approaches, with a baseline loss tolerance of $\sim$12\% using a 32-photon resource state and a foliated surface code. Nonlinear photonic architectures provide a route to dramatically improving practical implementations of fault-tolerant quantum computing.

Jonathan Lavoie, Blair Morrison

M. AbuGhanem

Abstract In the pursuit of scalable and fault-tolerant quantum computing architectures, photonic-based systems have emerged as a leading frontier. This comprehensive review examines recent advances across key industry and academic players—including iPronics, Jiuzhang (USTC), ORCA Computing, Photonic Inc., PsiQuantum, Quandela, Quix Quantum, TundraSystems, TuringQ, and Xanadu—analyzing their photonic quantum processors, current performance benchmarks, architectural designs, quantum software ecosystems, and strategies toward developing large-scale fault-tolerant photonic quantum computers. The article highlights groundbreaking experiments that leverage the unique advantages of photonic technologies and underscoring their transformative potential in the NISQ and early fault‑tolerant regimes. With the global photonics market projected to reach USD 837.8 billion by 2025, this work captures photonic quantum computing’s pivotal moment in the early fault-tolerant era, offering forward‑looking insights into how photonic quantum computers may reshape the future of quantum technologies.

Rui Asaoka, Yuuki Tokunaga, Rina Kanamoto +2 more

We analyze the requirements for fault-tolerant quantum computation with atom-atom gates based on cavity quantum electrodynamics (cQED) mediated by a photon with a finite pulse length. For short photon pulses, the distorted shape of the reflected pulses from the cQED system is a serious error source. In the previous study by Goto and Ichimura [Phys. Rev. A 82, 032311 (2010)], only the photon loss is minimized without considering the shape distortion to optimize the system parameters. Here we show an improved optimization method to minimize the infidelity due to the shape distortion and the photon losses in a well-balanced manner for the fault-tolerant scheme using probabilistic gates [Phys. Rev. A 80, 040303(R) (2009)]. Under this optimization, we discuss the fault-tolerant quantum computing requirement for short pulses. Finally, we show that reducing the cavity length is an effective way to reduce the errors of this type of gate in the case of short photon pulses.

I. S. Osborne