Logical qubits start outperforming physical qubits
Quantinuum closes in on breakeven point in quantum error correction
Broomfield, Colorado, August 4th, 2022 — Quantinuum researchers have hit a significant milestone by entangling logical qubits in a fault-tolerant circuit using real-time quantum error correction. The research, published in a new scientific paper that was released on August 3rd, is the first experimental comparison study of different quantum error correction codes in similar environments and presents a collection of several different experiments. These experiments include:
- The first demonstration of entangling gates between two logical qubits done in a fully fault-tolerant manner using real-time error correction
- The first demonstration of a logical entangling circuit that has higher fidelity than the corresponding physical circuit.
This milestone achievement is important because it marks the first time that logical qubits have been shown to outperform physical qubits — a critical step towards fault-tolerant quantum computers.
“Quantinuum’s trapped-ion quantum computing roadmap is designed around continuous upgrades, enabled our flexible architecture and our precision control capabilities. This combination provides for outstanding, first-of-its-kind achievements that help accelerate the entire industry,” said Tony Uttley, President and COO of Quantinuum.
David Hayes, a Theory and Architecture Technical Manager at Quantinuum and co-author of the new research paper, said the research moves quantum computing closer to the point where encoded circuits outperform more primitive operations.
“People have worked with error corrected qubits before, but they haven't reached this sort of special point where the encoded operation is working better than the primitive operation,” Hayes said. “The other thing that's new here is that in other experiments we're doing the error correction while we're doing the operations. An important next step for us is to get the error rate induced by the error correction itself down further."
The findings are described in the new research paper, “Implementing Fault-tolerant Entangling Gates on the Five-Qubit code and the Color Code”. The paper was recently published on the arXiv. Scientists used both the H1-1 and the H1-2 quantum computers, Powered by Honeywell, to compare the Five-Qubit error code and the Distance Three Color Code in these tests.
Quantum researchers are in the early days of experimental quantum error correction with a multitude of codes to test. Quantinuum researchers can explore a wider range of quantum error codes, compared to other quantum hardware designs, due to the architecture of the machine.
The System Model H1 uses a trapped-ion design and a quantum charged coupled device architecture (QCCD). Along with the inherent flexibility of this design, another strength is all-to-all connectivity. All the qubits are connected to each other which makes it easy to move information through chains of ions without creating multiple errors along the way.
“Instead of having to build a new machine every time we want to try a new code, we can just program the machine to run a different code, make the measurements and weigh the different pros and cons,” Hayes said.
Advancing quantum error correction
All forms of technology need error correction including servers in data centers and space probes sending transmissions back to Earth. For Quantinuum and other companies in the quantum computing sector, quantum error correction is one of the most important pillars of progress. Errors prevent quantum computers from producing reliable results before they are overwhelmed. Quantinuum’s researchers are working toward the milestone of fault tolerance, meaning the errors can be suppressed to arbitrarily low levels.
Natalie Brown, another co-author of the paper and an Advanced Physicist at Quantinuum, said that most classical error correction principles fail with quantum computers because of the basic nature of quantum mechanics.
“It becomes very difficult to suppress noise to very small levels, and that becomes a problem in quantum computing,” she said. “The most promising candidate was this quantum error correction, where we take the physical qubits, make a logical qubit.”
Logical qubits are groups of physical qubits working together to perform a computation. For each physical qubit used in a computation, other ancillary qubits perform a range of tasks such as spotting and correcting errors as they occur.
Ciaran Ryan-Anderson, a Senior Advanced Physicist at Quantinuum and also a co-author of the new paper, said the newest research paper builds on research performed in 2021 and published in Physical Review X. That work explained how researchers at Honeywell Quantum Solutions applied multiple rounds of quantum error correction to a single logical qubit.
“One of the first really important things to demonstrate was these repeated rounds of quantum error correction cycles,” he said.
That is one of several milestones on Ryan-Anderson’s quantum error correction checklist:
- Conduct repeated rounds of fault tolerant quantum error correction
- Feed forward and conditionally apply syndrome extraction
- Enable real-time determination of correction for a quantum error correction code
- Demonstrate general algorithmic real-time decoding
- Scale up quantum error correction with two logical qubits
- Hit the breakeven point when logical quantum computing starts to outperform physical quantum computing
“Quantinuum has achieved some of the milestones required to accomplish this now,” Ryan-Anderson said.
Five-Qubit Code vs. Color Code
Building upon the 2021 research involving one logical qubit, the newest research illustrates the Quantinuum team’s progress with quantum error correction and two logical qubits. The team tested two error codes familiar to quantum experts: the Five-Qubit Code and the Color Code. The Five-Qubit Code does not allow for a fault tolerant transversal gate using only two logical qubits. Researchers used “pieceable” fault tolerance to decompose an initially non-fault tolerant logical gate operation into pieces that are individually fault-tolerant. The Color Code, however, does allow the use of a transversal CNOT gate which is naturally fault-tolerant.
How the experiment worked
H1-2 can use up to 12 qubits and H1-1 can use up to 20. The Five-Qubit Code tested on H1-2 while the Color Code tested on H1-1. Both computers use the same surface electrode ion trap to control ytterbium ions as qubits. Ion transport to isolated gate zones with focused laser beams provides low crosstalk gate and mid-circuit measurement operations.
The researchers ran five experiments with different combinations of circuit elements to test the Five-Qubit Code and to understand the impact of fault tolerant design and circuit depth. The team found that the extra circuitry designed to increase fault tolerance had a negative impact on the overall fidelity of the logical operation, due to the large number of CNOT operations required.
The Color Code showed much better results due in part to the ability to use a transversal CNOT gate. The team ran seven experiments to investigate the fault tolerant potential of these codes. With the Color Code, the researchers found that the State Preparation and Measurement circuits benefitted from the addition of fault tolerant circuitry with a significant reduction of error rates: 99.94% for the logical qubits compared to 99.68% for the physical qubits. This was the only additional circuitry required to make the circuit fault tolerant from end-to-end, since the logical CNOT is transversal and naturally fault tolerant.
The researchers concluded that the “relatively economical fault tolerant circuitry of the Color Code will provide a better platform for computation than the qubit efficient five-qubit code.” Also, the researchers found that the Five-Qubit Code would be useful only in systems with far lower physical error rates than quantum computers have at this point in time.
Hayes said the team’s next step will be to surpass the breakeven point and provide proof of the work. “We are getting evidence that we're really darn close to that point, but there's a lot of work that needs to be done to actually prove it,” he said. “Just getting right there is not good enough, you have to actually get past it.”
A new classical+quantum connection
Another advance from this experiment is a new classical processor with enhanced capabilities which will be essential to scalable algorithmic decoders. The data from the classical functions were used to dictate the control flow and operations executed in the quantum program.
The decoders used in these experiments were partially written in Rust and compiled to WebAssembly (Wasm). The choice of Wasm provides an efficient, safe, and portable classical language to have functions that are callable from quantum programs.
The decoder implemented in Rust uses many high-level program constructs. The support for these features means that various scalable algorithmic decoders can be ergonomically implemented in various high-level languages that compile to Wasm (such as Rust, C, and C++) and called from quantum programs.
“It was pretty enabling for this particular experiment, and it'll be even more important for future experiments as these things get more and more complicated,” Hayes said.
Another advantage of the trapped ion architecture is the ability to do real-time decision making during the execution of the quantum circuit thanks to long coherence times and the ability to do mid-circuit measurement and reset qubits as needed.
“Our systems have very long coherence times which is super advantageous when integrating in the classical compute real-time decision making,” Hayes said.
The Honeywell Trademark is used under license from Honeywell International Inc. Honeywell International Inc. makes no representations or warranties with respect to this product. This product is produced by Quantinuum.
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.
Broomfield, CO, June 5th, 2026 — Quantinuum Inc. (Nasdaq: QNT) (“Quantinuum”) today announced the closing of its upsized initial public offering of 28,000,000 shares of its Class A common stock at an initial public offering price of $60.00 per share. All of the shares were offered by Quantinuum. The aggregate gross proceeds from the offering, before deducting underwriting discounts and commissions and other offering expenses were $1.68 billion. Quantinuum’s Class A common stock is listed on the Nasdaq Global Market under the ticker symbol “QNT.”
J.P. Morgan and Morgan Stanley (in alphabetical order) acted as joint lead active book-running managers for the offering; Jefferies and Evercore ISI also acted as active book-running managers; BofA Securities, UBS Investment Bank, Cantor, Mizuho, Needham & Company, Societe Generale and TD Cowen acted as joint-book running managers; and Craig-Hallum and Rosenblatt acted as co-managers for the offering.
A registration statement relating to this offering was declared effective by the Securities and Exchange Commission (the “SEC”) on June 3, 2026. A prospectus relating to and describing the terms of the offering has been filed with the SEC and is available on the SEC’s website at www.sec.gov. The offering is being made available only by means of a prospectus. Copies of the prospectus may be obtained from: J.P. Morgan Securities LLC, c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, New York 11717 or by email at prospectus-eq_fi@jpmchase.com and postsalemanualrequests@broadridge.com; Morgan Stanley & Co. LLC, 180 Varick Street, 2nd Floor, New York, New York 10014, Attention: Prospectus Department or by email at prospectus@morganstanley.com; Jefferies LLC, Attn: Equity Syndicate Prospectus Department, 520 Madison Avenue, New York, New York 10022, by telephone at (877) 821-7388 or by email at Prospectus_Department@Jefferies.com; or Evercore Group L.L.C., Attention: Equity Capital Markets, 55 East 52nd Street, 35th Floor, New York, New York 10055, by telephone at 888-474-0200 or by email at ecm.prospectus@evercore.com.
This press release does not constitute an offer to sell or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.
About Quantinuum
Quantinuum is a leading quantum computing company offering a full-stack platform designed to make quantum computing deployable in real-world environments. The company has commercially deployed multiple generations of quantum systems built on the well-established QCCD architecture, which it has implemented with novel designs and capabilities to achieve the industry’s highest accuracy levels based on average two-qubit gate fidelity as of December 31, 2025. Quantinuum has active engagements with market leaders across pharmaceuticals, material science, financial services, and government and industrial markets. Quantinuum’s headquarters is in Broomfield, Colorado, with additional facilities across the United States, United Kingdom, Germany, Japan, Qatar and Singapore.
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Broomfield, CO, June 3rd, 2026 – Quantinuum Inc. (“Quantinuum”) today announced the pricing of the upsized initial public offering of 28,000,000 shares of its Class A common stock at a price to the public of $60.00 per share. Quantinuum has granted the underwriters a 30-day option to purchase up to an additional 4,200,000 shares of its Class A common stock to cover over-allotments at the initial public offering price, less underwriting discounts and commissions.
The shares of Class A common stock are expected to begin trading on the Nasdaq Global Market on June 4, 2026 under the ticker symbol “QNT.” The offering is expected to close on June 5, 2026, subject to customary closing conditions.
J.P. Morgan and Morgan Stanley (in alphabetical order) are acting as joint lead active book-running managers for the offering; Jefferies and Evercore ISI are also acting as active book-running managers; BofA Securities, UBS Investment Bank, Cantor, Mizuho, Needham & Company, Societe Generale and TD Cowen are acting as joint-book running managers; and Craig-Hallum and Rosenblatt are acting as co-managers for the offering.
A registration statement relating to this offering was declared effective by the Securities and Exchange Commission on June 3, 2026. The offering is being made available only by means of a prospectus. Copies of the prospectus, when available, may be obtained from: J.P. Morgan Securities LLC, c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, New York 11717 or by email at prospectus-eq_fi@jpmchase.com and postsalemanualrequests@broadridge.com; Morgan Stanley & Co. LLC, 180 Varick Street, 2nd Floor, New York, New York 10014, Attention: Prospectus Department or by email at prospectus@morganstanley.com; Jefferies LLC, Attn: Equity Syndicate Prospectus Department, 520 Madison Avenue, New York, New York 10022, by telephone at (877) 821-7388 or by email at Prospectus_Department@Jefferies.com; or Evercore Group L.L.C., Attention: Equity Capital Markets, 55 East 52nd Street, 35th Floor, New York, New York 10055, by telephone at 888-474-0200 or by email at ecm.prospectus@evercore.com.
This press release does not constitute an offer to sell or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.
About Quantinuum
Quantinuum is a leading quantum computing company offering a full-stack platform designed to make quantum computing deployable in real-world environments. The company has commercially deployed multiple generations of quantum systems built on the well-established QCCD architecture, which it has implemented with novel designs and capabilities to achieve the industry’s highest accuracy levels based on average two-qubit gate fidelity as of December 31, 2025. Quantinuum has active engagements with market leaders across pharmaceuticals, material science, financial services, and government and industrial markets. Quantinuum’s headquarters is in Broomfield, Colorado, with additional facilities across the United States, United Kingdom, Germany, Japan, Qatar and Singapore.
Quantinuum:
Quantinuum Investor Relations
investors@quantinuum.com
(855) 888-7686
June 2nd, 2026, Tokyo, Japan — Quantinuum, a leading quantum computing company, announced today that it has signed a non-binding Memorandum of Understanding (MOU) with Mitsubishi Electric Corporation, a recognized global leader in the manufacturing, marketing, and sale of electrical and electronic equipment and systems, to establish a framework for a strategic partnership aiming at accelerating the development of quantum computing applications for advanced industrial engineering and design.
The agreement creates a foundation for the companies to jointly identify high-impact industrial use cases and explore quantum and hybrid quantum-classical approaches for next-generation engineering workflows. Expected initial areas of focus include computer-aided engineering (CAE), such as computational fluid dynamics (CFD), and broader simulation and design applications utilizing logical qubit operations on Quantinuum’s quantum platform.
“We are pleased to begin this collaboration with Mitsubishi Electric as we work toward meaningful quantum utility to industrial engineering,” said Dr. Rajeeb Hazra, President and CEO of Quantinuum. “By combining Quantinuum’s leading quantum computing capabilities with Mitsubishi Electric’s deep engineering expertise, we aim to address some of the world’s most complex design and simulation challenges.”
Under the envisaged partnership, Quantinuum would provide Mitsubishi Electric with access to its high-fidelity trapped-ion quantum systems and expert consultation on quantum algorithm development. Mitsubishi Electric would contribute domain expertise in electromagnetic field analysis, structural analysis, and thermal fluid simulation across a wide range of industrial applications such as factory automation, energy and public utilities, air conditioning, and building systems.
“We are delighted to initiate discussions with Quantinuum to advance a strategic quantum computing partnership under this MOU,” said Mikio Takabayashi, Senior General Manager, Information Technology R&D Center of Mitsubishi Electric. “By integrating manufacturing expertise with digital insights, we aim to evaluate the feasibility and potential applications of quantum technologies in industrial engineering, while generating new ideas and exploring use cases that have the potential to contribute to society and the environment.”
The MOU reflects a shared recognition that near-term engagement with quantum computing may create long-term strategic advantages as the technology continues its advance toward commercial adoption. The companies believe that organizations that act early will be better positioned to help shape use cases, build proprietary expertise and secure intellectual property rights, and help secure access to emerging quantum infrastructure and amid growing demand.
Through the MOU, the companies will evaluate opportunities for future collaboration that have the potential to accelerate technological innovation and create sustained value for global industry.
About Quantinuum
Quantinuum is a leading quantum computing company offering a full-stack platform designed to make quantum computing deployable in real-world environments. The company has commercially deployed multiple generations of quantum systems built on the well-established QCCD architecture, which it has implemented with novel designs and capabilities to achieve the industry’s highest accuracy levels based on average two-qubit gate fidelity.[1] Quantinuum has active engagements with market leaders across pharmaceuticals, material science, financial services, and government and industrial markets.
The company has a global workforce of approximately 700 employees, including top scientists and researchers. Over 70% of its technology team hold PhDs or Master’s degrees. Quantinuum’s headquarters is in Broomfield, Colorado, with additional facilities across the United States, United Kingdom, Germany, Japan, Qatar, and Singapore.
For more information, please visit www.quantinuum.com.
About Mitsubishi Electric Corporation
Guided by its corporate philosophy, Mitsubishi Electric Corporation (TOKYO: 6503) places sustainability at the core of its operations and values stakeholder trust—encompassing society, customers, shareholders and employees. In pursuing profitability, capital efficiency and growth, Mitsubishi Electric works closely alongside customers to develop value-added solutions that address today’s complex challenges while enhancing the company’s sustainable corporate value. Founded in 1921, Mitsubishi Electric has over a century of experience in delivering reliable, high-quality products and solutions. With over 200 group companies and approximately 150,000 employees worldwide, the company is a recognized global leader in manufacturing, marketing and selling electrical and electronic equipment and systems across a broad range of sectors, including public utility systems, energy systems, defense and space systems, factory automation systems, automotive equipment, building systems, air conditioning systems & home products, digital innovations, and semiconductor & devices. Mitsubishi Electric recorded consolidated revenue of 5,894.7 billion yen (U.S.$ 36.8 billion*) in the fiscal year that ended on March 31, 2026. For more information, please visit www.MitsubishiElectric.com
*JPY 160=USD 1, the approximate rate on the Tokyo Foreign Exchange Market on March 31, 2026
Cautionary Statement Concerning Forward-Looking Statements
This press release contains certain statements that may be deemed “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include all statements that are not historical facts. The words “anticipate,” “assume,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “future,” “will,” “seek,” “foreseeable,” the negative version of these words, or similar terms and phrases are intended to identify forward-looking statements. Such statements are based on certain assumptions and assessments made by our management in light of their experience and their perception of historical trends, current economic and industry conditions, expected future developments and other factors they believe to be appropriate. The forward-looking statements included in this release are also subject to a number of material risks and uncertainties, including but not limited to economic, competitive, governmental, and technological factors affecting our operations, markets, products, services and prices. New factors emerge from time to time, and it is not possible for Quantinuum to predict all such factors. Any forward-looking statement speaks only as of the date on which it is made, and, except as required by law, Quantinuum does not undertake any obligation to update or revise any forward-looking statement, whether as a result of new information, future events or otherwise.
[1] As of December 31, 2025.