Quantinuum’s H1 quantum computer successfully executes a fully fault-tolerant algorithm with three logically-encoded qubits

A multidisciplinary team from Quantinuum, QuTech (Delft University of Technology) and the University of Stuttgart used the H1 quantum computer to demonstrate a noteworthy advance in fault-tolerant operations

September 28, 2023

Cambridge, UK and Broomfield, Colorado, September 28th, 2023 Fault-tolerant quantum computers that offer radical new solutions to some of the world’s most pressing problems in medicine, finance and the environment, as well as facilitating a truly widespread use of AI, are driving global interest in quantum technologies. Yet the various timetables that have been established for achieving this paradigm require major breakthroughs and innovations to remain achievable, and none is more pressing than the move from merely physical qubits to those that are fault-tolerant.

In one of the first meaningful steps along this path, scientists from Quantinuum, the world’s largest integrated quantum computing company, along with collaborators, have demonstrated the first fault-tolerant method using three logically-encoded qubits on the Quantinuum H1 quantum computer, Powered by Honeywell, to perform a mathematical procedure.

Fault-tolerant quantum computing methods are expected to open the way for practical solutions to real-world problems across domains such as molecular simulation, artificial intelligence, optimization, and cybersecurity. Following a succession of important breakthroughs in recent years in hardware, software and error correction, today's results announced by Quantinuum in a new paper on the arXiv, "Fault-Tolerant One-Bit Addition with the Smallest Interesting Colour Code" are a natural step forward, and reflect the growing pace of progress.

Many companies and research groups are focused on achieving fault-tolerance by handling the noise that naturally arises when a quantum computer performs its operations. Quantinuum is a proven pioneer, achieving previous firsts such as demonstrating entangling gates between two logical qubits in a fully fault-tolerant manner using real-time error correction, and simulating the hydrogen molecule with two logically-encoded qubits

By performing one-bit addition using the smallest-known fault-tolerant circuit, the team achieved an error rate almost an order of magnitude lower, at ~1.1x10-3 compared to ~9.5x10-3 for the unencoded circuit. The error suppression observed was made possible by the physical error rates of the quantum charge-coupled device (QCCD) architecture used in Quantinuum’s H-Series quantum computers, which are lower than in any other systems known to date. These error rates fall within the range at which fault-tolerant algorithms become feasible.

Ilyas Khan, Chief Product Officer and Founder at Quantinuum, said: “In addition to continuing to provide the quantum ecosystem with evidence of what is possible in these early days of quantum computing, the current demonstration is noteworthy for its ingenuity. The ion trap architecture of our H-Series offers the lowest physical error rates and the flexibility derived from qubit transport, which allows users of our hardware to implement a much wider choice of error-correcting codes, and that is what made this possible. Watch out for further important computational advances in the coming period as we link up the quality of our hardware with tasks that are meaningful in the real world.”

Low-overhead logical Clifford gates, in combination with the transversal CCZ gate of the three-dimensional color code, enabled the team to reduce the number of two-qubit gates and measurements required for one-bit addition, from over 1000, to 36.

Ben Criger, Senior Research Scientist at Quantinuum, and principal investigator on the paper, said: “The CCZ gate, which we’ve demonstrated here, is a key ingredient in Shor’s algorithm, quantum Monte Carlo, topological data analysis, and a host of other quantum algorithms. This result proves that real hardware is now capable of running all the essentials of fault-tolerant quantum computing – state preparation, Clifford gates, non-Clifford gates and logical measurement – together.”

About Quantinuum 

Quantinuum is the world’s largest integrated standalone quantum computing company, formed by the combination of Honeywell Quantum Solutions’ world-leading hardware and Cambridge Quantum’s class-leading middleware and applications. Science-led and enterprise-driven, Quantinuum accelerates quantum computing and the development of applications across chemistry, cybersecurity, finance and optimization. Its focus is to create scalable and commercial quantum solutions to solve the world’s most pressing problems in fields such as energy, logistics, climate change, and health. The company employs over 480 individuals, including 350+ scientists and engineers, at eight sites across the United States, Europe, and Japan. For more information, please visit https://www.quantinuum.com

The Honeywell trademark is used under license from Honeywell International Inc. Honeywell makes no representations or warranties with respect to this service.

About Quantinuum

Quantinuum, the world’s largest integrated quantum company, pioneers powerful quantum computers and advanced software solutions. Quantinuum’s technology drives breakthroughs in materials discovery, cybersecurity, and next-gen quantum AI. With over 500 employees, including 370+ scientists and engineers, Quantinuum leads the quantum computing revolution across continents. 

April 3, 2025
Quantinuum Selected by DARPA to Advance to First Stage of Quantum Benchmarking Initiative

Broomfield, CO, April 3rd, 2025 — Quantinuum, the industry leader in quantum computing with the world’s most powerful quantum computer, has been selected by the Defense Advanced Research Projects Agency (DARPA), a research and development agency of the United States Department of Defense, to participate in the first stage of the agency’s Quantum Benchmarking Initiative (QBI).

QBI aims to assess the feasibility of building an industrially useful quantum computer by 2033. Successful QBI performers will advance through stages A, B, and C; Stage A requires performers to describe their utility-scale quantum computer with a path to near-term realization, where utility-scale means the computational value exceeds costs.

As validated in a recent independent benchmarking study by a group of institutions at the forefront of quantum computing research, Quantinuum’s quantum systems are the highest performing in the industry. Last year, Quantinuum published its development roadmap, outlining a path to a universal, fully-fault tolerant quantum computer by 2029. Beyond this public roadmap, Quantinuum plans to scale to even larger machines in the early part of the 2030s, aligning with the objectives of QBI.

“We are honored to collaborate with DARPA and look forward to working closely with their test and evaluation team as they assess our roadmap and technological approach,” said Dr. Rajeeb Hazra, President and CEO of Quantinuum. “With our roadmap firmly on track, we are confident in our ability to deliver on DARPA’s objectives for QBI.”

Microsoft and NVIDIA will take part in Quantinuum’s Stage A effort, building on their long-standing collaborations with Quantinuum in advancing commercially scalable quantum computing.

About Quantinuum

Quantinuum is the world leader in quantum computing. The company’s quantum systems deliver the highest performance across all industry benchmarks. Quantinuum’s over 550 employees, including 370+ scientists and engineers, across the US, UK, Germany, and Japan, are driving the quantum computing revolution.  

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April 2, 2025
Quantinuum’s ‘Quantum Origin’ Becomes First Software Quantum Random Number Generator to Achieve NIST Validation

Broomfield, CO, April 2nd, 2025 — Quantinuum, the industry leader in quantum computing with the world’s highest performing quantum computer, today announced that  Quantum Origin, the company’s software Quantum Random Number Generator (QRNG), has received National Institute of Standards and Technology (NIST) validation. Quantum Origin is the first software QRNG to achieve this validation, establishing it as a crucial tool for federal agencies and agency partners in their mandated migration to post-quantum cryptography (PQC) under National Security Memorandum 10. This achievement will help strengthen cybersecurity in the age of PQC.

Quantum Origin generates mathematically proven randomness — a capability unmatched by hardware-based QRNGs or traditional pseudo-random number generators. Unlike hardware solutions that require specialized equipment and can be affected by environmental factors, Quantum Origin delivers consistent, proven randomness through flexible software deployment. Proven quantum randomness is an essential foundation for comprehensive quantum security strategy alongside PQC.

"The evolving threat landscape demands a new era of cybersecurity solutions for governments, enterprises, and critical infrastructure," said Dr. Rajeeb Hazra, President and CEO of Quantinuum. "Quantinuum is at the forefront of this transformation, driving innovation in quantum cybersecurity. Our recent certified randomness demonstration with JPMorganChase, and our NIST-validated Quantum Origin platform are just two examples of how we are deepening our portfolio to meet this critical need."

Quantum Origin is delivered entirely as self-contained software, making it adaptable to diverse environments from cloud solutions to highly sensitive systems. It can be deployed with zero network connectivity, enabling protection for air-gapped networks and confidential environments where traditional hardware-based QRNGs cannot operate effectively. It provides quantum-enhanced security without impacting the size, weight, and power (SWaP) requirements of existing systems, a critical consideration for resource-constrained deployments.

U.S. Made using Quantinuum's quantum computers based in Colorado, Quantum Origin helps mitigate supply chain risks associated with foreign-sourced hardware components. It is designed to integrate seamlessly with existing NIST-approved cryptographic systems without requiring recertification. With this NIST validation, organizations can now accelerate their adoption of quantum-enhanced security within existing compliance frameworks.

Visit https://www.quantinuum.com/quantum-origin to learn how Quantum Origin can strengthen federal and enterprise cryptographic systems today.

About Quantinuum

Quantinuum is the world leader in quantum computing. The company’s quantum systems deliver the highest performance across all industry benchmarks. Quantinuum’s over 550 employees, including 370+ scientists and engineers, across the US, UK, Germany, and Japan, are driving the quantum computing revolution.

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March 26, 2025
JPMorganChase, Quantinuum, Argonne National Laboratory, Oak Ridge National Laboratory and University of Texas at Austin advance the application of quantum computing to potential real-world use cases beyond the capabilities of classical computing
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