Fault-tolerant quantum computing (FTQC) has the potential to reliably execute complex calculations by overcoming the problems raised from the errors and noise inherent in quantum systems. This paper builds upon a 2025 report issued by the National Academy of Technologies of France. After recalling the principles that underly the so-called "quantum advantage," the use of error-correcting codes in the design of fault-tolerant quantum computers is discussed. Also explored are the five most advanced physical technologies that can be used to build such computers and the challenges of scaling up to a sufficient size to run useful applications. After highlighting the limits of monolithic qubit integration, the focus turns to increasing the number of available physical qubits by interconnecting several quantum processing modules. The paper concludes with a discussion of technical and economic environments, their performance benchmarks, and their future coexistence with other computing technologies and with supercomputers.
Fault-tolerant quantum computing (FTQC) has the potential to reliably execute complex calculations by overcoming the problems raised from the errors and noise inherent in quantum systems. This paper builds upon a 2025 report issued by the National Academy of Technologies of France. After recalling the principles that underly the so-called "quantum advantage," the use of error-correcting codes in the design of fault-tolerant quantum computers is discussed. Also explored are the five most advanced physical technologies that can be used to build such computers and the challenges of scaling up to a sufficient size to run useful applications. After highlighting the limits of monolithic qubit integration, the focus turns to increasing the number of available physical qubits by interconnecting several quantum processing modules. The paper concludes with a discussion of technical and economic environments, their performance benchmarks, and their future coexistence with other computing technologies and with supercomputers.
Quantum error correction (QEC) has transitioned from a theoretical promise to an experimental reality, with recent demonstrations of below-threshold logical qubits marking a turning point in the quest for fault-tolerant quantum computing. Over the past five years, breakthroughs in surface code implementations, low-latency decoders, and improved physical qubit fidelities have brought us to the brink of scalable logical qubit systems. Yet the road to practical quantum advantage remains steep: correlated noise, cryogenic control complexity, and the resource overhead of magic state distillation still pose major barriers. Here, we synthesize recent progress across superconductng, trapped-ion, and neutral-atom platforms, assess the state-of the-art in topological and LDPC codes, and highlight engineering challenges that must be overcome to achieve systems with thousands of logical qubits. We argue that the 2025-2035 decade will be decisive for quantum computing, with success hinging on co-design of hardware, software, and algorithms. This perspective outlines a roadmap for the next generation of fault tolerant systems and discusses the societal and economic implications of entering the era of practical quantum advantage.
The limited qubit resources of current quantum processing units (QPUs), together with their susceptibility to operational imperfections, environmental noise, and error propagation, not only degrade computational fidelity but also constrain the scalability required for utility-scale quantum computing. Consequently, the transition from monolithic architectures to distributed quantum computing (DQC), supported by distributed quantum error-correcting codes (QECCs), is emerging as a promising paradigm for large-scale fault-tolerant quantum computing (FTQC). This transition represents a full-stack challenge that requires coordinated advances in quantum architecture, fault-tolerant gate operations, and classical–quantum co-processing and control. In this paper, we review the theoretical foundations and practical realization of large-scale FTQC. We first explore major families of QECCs, including topological, qLDPC, subsystem, and dynamical codes, with emphasis on code construction, syndrome extraction, and decoding. We then review the implementation of fault-tolerant universal gate sets at the physical and logical levels, followed by entanglement generation, distribution, and purification for distributed architectures. Finally, we outline open challenges and future research directions in theory, architecture, and implementation, highlighting the role of distributed fault-tolerant designs in next-generation utility-scale quantum computing.
To run a practical size of quantum program, computer architects have been making tremendous efforts to realize fault-tolerant quantum computing (FTQC) which constructs a fault-tolerant logical qubit by correcting many erroneous physical qubits during runtime. However, it is extremely challenging to build a full-stack FTQC system consisting of heterogeneous stacks, where each stack incurs unique challenges regarding the fault tolerance and the interplay of the challenges incurs very complicated overall design choice problem. Therefore, computer architects must fully understand stack-specific optimizations and their system-level trade-offs, and resolve all the challenges together. In this article, we first introduce critical design challenges in architecting an FTQC system built on the superconducting technology, and then present our research outcomes to resolve the challenges to build an FTQC system realizing thousands of logical qubits. We also outline near-future directions to resolve the remaining challenges and provide insights toward realizing more scalable future FTQC systems.
Recent progress in quantum information has led to the start of several large national and industrial efforts to build a quantum computer. Researchers are now working to overcome many scientific and technological challenges. The program's biggest obstacle, a potential showstopper for the entire effort, is the need for high-fidelity qubit operations in a scalable architecture. This challenge arises from the fundamental fragility of quantum information, which can only be overcome with quantum error correction. 1 In a fault-tolerant quantum computer the qubits and their logic interactions must have errors below a threshold: scaling up with more and more qubits then brings the net error probability down to appropriate levels needed for running complex algorithms. Reducing error requires solving problems in physics, control, materials and fabrication, which differ for every implementation. I explain here the common key driver for continued improvement - the metrology of qubit errors.
Quantum computing has showcased potentials to address classically unsolvable problems and attracted research investigation all around the world. However, quantum devices are inherently noisy and create hurdles from true quantum supremacy. Despite researchers have strived to demonstrate quantum advantages at small scales in the noisy intermediate-scale quantum (NISQ) era, we are now at the turning point to craft fault tolerant quantum computers (FTQC) for large scale quantum computing. In this paper, we review the current status of available error control techniques, discuss the missing pieces of each technique for their practical adaptation, and envision the necessity to synergize them across vast design stacks, to enable fault tolerance in quantum computing.
The transition from classical to quantum computation marks a shift from deterministic binary logic to a probabilistic, entanglement‑driven framework able to address problems beyond classical reach. Today’s Noisy Intermediate ‑ Scale Quantum era features devices that lack full error correction yet already point toward larger, modular systems designed for fault‑tolerant operation. This paper examines the evolving paradigm shift from classical and NISQ ‑ era machines toward practical fault‑tolerant quantum computing, focusing on how advances in physical qubit technologies, control architectures, and error‑correction strategies are converging to bridge noisy prototypes and scalable, useful machines. We synthesize insights from historical semiconductor scaling trends, contemporary roadmaps from leading institutions and industry, and emerging modular designs with real‑time error decoding. Our analysis shows that while challenges around decoherence, connectivity, and classical co‑processing remain, coordinated progress in hardware, control, and software is laying a coherent foundation for future quantum platforms. The work concludes that quantum computing is maturing into a strategically significant paradigm, poised to redefine the limits of computation in simulation, optimization, and secure communication.