[Paper Review] Quantum computing at the quantum advantage threshold: a down-to-business review

Aleksey K. Fedorov, N. Gisin+2 more|arXiv (Cornell University)|Mar 31, 2022

Quantum Computing Algorithms and Architecture35 citations

TL;DR

A broad, accessible survey of quantum computing as it sits at the threshold of quantum advantage, covering models, platforms, applications, software, and market outlook.

ABSTRACT

It is expected that quantum computers would enable solving various problems that are beyond the capabilities of the most powerful current supercomputers, which are based on classical technologies. In the last three decades, advances in quantum computing stimulated significant interest in this field from industry, investors, media, executives, and general public. However, the understanding of this technology, its current capabilities and its potential impact in these communities is still lacking. Closing this gap requires a complete picture of how to assess quantum computing devices' performance and estimate their potential, a task made harder by the variety of quantum computing models and physical platforms. Here we review the state of the art in quantum computing, promising computational models and the most developed physical platforms. We also discuss potential applications, the requirements posed by these applications and technological pathways towards addressing these requirements. Finally, we summarize and analyze the arguments for the quantum computing market's further exponential growth. The review is written in a simple language without equations, and should be accessible to readers with no advanced background in mathematics and physics.

Motivation & Objective

• Explain the current state of quantum computing across models, platforms, and applications.
• Clarify how to assess quantum devices and their readiness for real-world tasks.
• Identify challenges, benchmarks, and pathways toward fault tolerance and error correction.
• Discuss the potential market dynamics and national programs accelerating quantum technology.

Proposed method

• Survey and synthesize the landscape of quantum computing models (gate-based, one-way, adiabatic, variational) and non-universal simulators.
• Review physical platforms (solid-state, atoms/ions, optics) and their architectural options.
• Discuss error mechanisms, NISQ devices, and fault-tolerant approaches including topological protection.
• Outline applications spanning basic science, optimization, chemistry, cryptanalysis, and machine learning.
• Propose a framework combining technical benchmarks and user-oriented criteria for assessing readiness and potential.
• Provide a market and policy context with national programs and industry milestones.

Experimental results

Research questions

• RQ1 What are the main quantum computing models and platforms currently advancing toward practical advantage?
• RQ2 How can quantum devices be benchmarked and compared given their diverse architectures and error modes?
• RQ3 What are the most promising practical applications that could demonstrate quantum advantage, and what are the required technological milestones?
• RQ4 How do national programs and market dynamics influence the trajectory toward a quantum computing industry?
• RQ5 What software, validation, and ecosystem developments are needed to reach fault-tolerant quantum computing?

Key findings

• NISQ devices exist with dozens of qubits and limited gate depths, showing limited practical advantage but not yet solving real-world problems.
• Quantum advantage is framed as tasks where quantum devices outperform classical ones, particularly in sampling and distribution problems; scalable, fault-tolerant implementations remain essential.
• Multiple quantum models (gate-based, one-way, adiabatic, variational) and platforms (solid-state, atoms/ions, optics) offer complementary pathways toward scalability.
• Validation and benchmarking challenges persist due to the diversity of hardware and algorithms, necessitating a two-pronged assessment: technical readiness and user-oriented criteria (cost, speed, task range).
• The market outlook is positive with growing national programs and industry interest, yet wide-scale quantum advantage in practical applications awaits future developments.
• Error correction, noise resilience, and topological protection are central to progressing from NISQ to fault-tolerant quantum computing.