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

July 12, 2023

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)

TOKYO, JAPAN, CAMBRIDGE, UK, and BROOMFIELD, CO, 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.



Kaniah Konkoly-Thege

Kaniah is Chief Legal Counsel and SVP of Government Relations for Quantinuum. In her previous role, she served as General Counsel, Honeywell Quantum Solutions. Prior to Honeywell, she was General Counsel, Honeywell Federal Manufacturing and Technologies, LLC, and Senior Attorney, U.S. Department of Energy. She was Lead Counsel before the Civilian Board of Contract Appeals, the Merit Systems Protection Board, and the Equal Employment Opportunity Commission. Kaniah holds a J.D. from American University, Washington College of Law and B.A., International Relations and Spanish from the College of William and Mary.

Jeff Miller

Jeff Miller is Chief Information Officer for Quantinuum. In his previous role, he served as CIO for Honeywell Quantum Solutions and led a cross-functional team responsible for Information Technology, Cybersecurity, and Physical Security. For Honeywell, Jeff has held numerous management and executive roles in Information Technology, Security, Integrated Supply Chain and Program Management. Jeff holds a B.S., Computer Science, University of Arizona. He is a veteran of the U.S. Navy, attaining the rank of Commander.

Matthew Bohne

Matthew Bohne is the Vice President & Chief Product Security Officer for Honeywell Corporation. He is a passionate cybersecurity leader and executive with a proven track record of building and leading cybersecurity organizations securing energy, industrial, buildings, nuclear, pharmaceutical, and consumer sectors. He is a sought-after expert with deep experience in DevSecOps, critical infrastructure, software engineering, secure SDLC, supply chain security, privacy, and risk management.

Todd Moore

Todd Moore is the Global Vice President of Data Encryption Products at Thales. He is responsible for setting the business line and go to market strategies for an industry leading cybersecurity business. He routinely helps enterprises build solutions for a wide range of complex data security problems and use cases. Todd holds several management and technical degrees from the University of Virginia, Rochester Institute of Technology, Cornell University and Ithaca College. He is active in his community, loves to travel and spends much of his free time supporting his family in pursuing their various passions.

John Davis

Retired U.S. Army Major General John Davis is the Vice President, Public Sector for Palo Alto Networks, where he is responsible for expanding cybersecurity initiatives and global policy for the international public sector and assisting governments around the world to prevent successful cyber breaches. Prior to joining Palo Alto Networks, John served as the Senior Military Advisor for Cyber to the Under Secretary of Defense for Policy and served as the Acting Deputy Assistant Secretary of Defense for Cyber Policy.  Prior to this assignment, he served in multiple leadership positions in special operations, cyber, and information operations.