Quantum Chemistry Progresses Meaningfully Towards a Fault Tolerant Regime Using Logical Qubits

In a major scientific first, quantum chemistry experts at Quantinuum have used a partially fault tolerant algorithm run on logical qubits to simulate the hydrogen molecule (H2)

July 12, 2023

Tokyo, Japan, Cambridge, UK, and Broomfield, Colorado, July 12th, 2023 — Quantinuum, the world’s largest quantum computing company, has become the first to simulate a chemical molecule by implementing a partially fault tolerant algorithm on a quantum processor using logical qubits. 

This essential step towards using quantum computers to speed up molecular discovery, with better modeling of chemical systems, reduces the time to generate commercial and economic value.

Quantinuum scientists, led from Japan, used three logical qubits on Quantinuum’s H1 quantum computer to calculate the ground state energy of the hydrogen molecule (H2) using an algorithm for early fault tolerant devices called stochastic quantum phase estimation.

It is already known that many algorithms that can be used on today’s “NISQ” era quantum computers will not scale to larger problems. The phase estimation technique used in this experiment with logical qubits has better potential to scale but is challenging to implement on today’s quantum computers because it requires very complex circuits, which are prone to failing due to noise. 

Dr. Raj Hazra, CEO of Quantinuum, said: “Today’s announcement turns a page for quantum chemistry on quantum computers, moving us towards the era of early fault tolerance. This achievement is testament to the dedication of the hardware and software teams at Quantinuum, who consistently demonstrate their ability to achieve world-class results. It was made possible thanks to the H1 quantum computer which brings together high-fidelity gate operations, all-to-all connectivity and conditional logic, with the truly world-leading algorithms, methods and error handling techniques offered by our InQuanto chemistry platform.”

In a scientific preprint paper, “Demonstrating Bayesian Quantum Phase Estimation with Quantum Error Detection”, the team of scientists led by Dr. Kentaro Yamamoto report they have overcome this challenge by creating and using logical qubits achieved with a newly developed error detection code designed for the H-series quantum hardware*. The code saved quantum resources by immediately discarding a calculation if it detected qubits that had produced errors during the computation process.

When combined with the low noise of the H-Series hardware and the capabilities of the Quantinuum Software InQuanto™, researchers were able to run these complex circuits for the first time, producing more accurate simulation results than those achieved without the error detection code. Creating and using logical qubits with error detection is a prerequisite for the more advanced error correction, which provides real-time protection for a quantum computer against various forms of “noise”.

Dr. Kentaro Yamamoto, Senior Researcher at Quantinuum, said: “Simulating the hydrogen molecule and getting such good results with logical qubits is an excellent experimental result and reminds us how fast we continue to progress. This result may reflect the start of a new chapter for quantum computing professionals, where we can begin to adopt partially fault tolerant algorithms on near-term devices, using all the techniques that will ultimately be required for future large-scale quantum computing.”

For scientific researchers and industrial enterprises in sectors such as healthcare, energy, automotive and manufacturing, who invest heavily in researching future molecules and materials, this demonstration implies that the time to useful quantum computing continues to get nearer.

This demonstration, which was run on Quantinuum’s System Model H1 quantum computer, Powered by Honeywell, will be integrated into future versions of its industry-leading quantum computational chemistry platform, InQuanto, allowing industrial companies and academic researchers to explore the use of partially fault-tolerant algorithms run on quantum computers for material and molecular modeling.

* For more information about the error detection code, see “Protecting Expressive Circuits with a Quantum Error Detection Code”

About Quantinuum

Quantinuum is the world’s largest 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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