Quantinuum and Microsoft achieve breakthrough that unlocks a new era of reliable quantum computing
Quantinuum’s System Model H2 enabled Microsoft’s qubit-virtualization system to generate the most reliable logical qubits ever recorded, a breakthrough with wide ranging implications for everyone in quantum computing, accelerating progress and challenging current assumptions about the timeline toward large scale reliable quantum computing.
By Ilyas Khan, Chief Product Officer and Jenni Strabley, Senior Director Offering Management
Quantinuum and Microsoft have announced a vital breakthrough in quantum computing that Microsoft described as “a major achievement for the entire quantum ecosystem.”
By combining Microsoft’s innovative qubit-virtualization system with the unique architectural features and fidelity of Quantinuum’s System Model H2 quantum computer, our teams have demonstrated the most reliable logical qubits on record with logical circuit error rates 800 times lower than the corresponding physical circuit error rates.
This achievement is not just monumental for Quantinuum and Microsoft, but it is a major advancement for the entire quantum ecosystem. It is a crucial milestone on the path to building a hybrid supercomputing system that can truly transform research and innovation across many industries for decades to come. It also further bolsters H2’s title as the highest performing quantum computer in the world.
Entering a new era of quantum computing
Historically, there have been widely held assumptions about the physical qubits needed for large scale fault-tolerant quantum computing and the timeline to quantum computers delivering real-world value. It was previously thought that an achievement like this one was still years away from realization – but together, Quantinuum and Microsoft proved that fault-tolerant quantum computing is in fact a reality.
In enabling today’s announcement, Quantinuum’s System Model H2 becomes the first quantum computer to advance to Microsoft’s Level 2 – Resilient phase of quantum computing – an incredible milestone. Until now, no other computer had been capable of producing reliable logical qubits.
Using Microsoft’s qubit-virtualization system, our teams used reliable logical qubits to perform 14,000 individual instances of a quantum circuit with no errors, an overall result that is unprecedented. Microsoft also demonstrated multiple rounds of active syndrome extraction – an essential error correction capability for measuring and detecting the occurrence of errors without destroying the quantum information encoded in the logical qubit.
As we prepare to bring today’s logical quantum computing breakthrough to commercial users, there is palpable anticipation about what this new era means for our partners, customers, and the global quantum computing ecosystem that has grown up around our hardware, middleware, and software.
Collaborating to reach a new era
To understand this achievement, it is helpful to shed some light on the joint work that went into it. Our breakthrough would not have been possible without the close collaboration of the two exceptional teams at Quantinuum and Microsoft over many years.
Building on a relationship that stretches back five years, we collaborated with Microsoft Azure Quantum at a very deep level to best execute their innovative qubit-virtualization system, including error diagnostics and correction. The Microsoft team was able to optimize their error correction innovation, reducing an original estimate of 300 required physical qubits 10-fold, to create four logical qubits with only 30 physical qubits, bringing it into scope for the 32-qubit H2 quantum computer.
This massive compression of the code and efficient virtualization challenges a consensus view about the resources needed to do fault-tolerant quantum computing, where it has been routinely stated that a logical qubit will require hundreds, even thousands of physical qubits. Through our collaboration, Microsoft’s far more efficient encoding was made possible by architectural features unique to the System Model H2, including our market-leading 99.8% two-qubit gate fidelity, 32 fully-connected qubits, and compatibility with Quantum Intermediate Representation (QIR).
Thanks to this powerful combination of collaboration, engineering excellence, and resource efficiency, quantum computing has taken a major step into a new era, introducing reliable logical qubits which will soon be available to industrial and research users.
Understanding today’s error correction breakthrough
It is widely recognized that for a quantum computer to be useful, it must be able to compute correctly even when errors (or faults) occur – this is what scientists and engineers describe as fault-tolerance.
In classical computing, fault-tolerance is well-understood and we have come to take it for granted. We always assume that our computers will be reliable and fault-free. Multiple advances over the course of decades have led to this state of affairs, including hardware that is incredibly robust and error rates that are very low, and classical error correction schemes that are based on the ability to copy information across multiple bits, to create redundancy.
Getting to the same point in quantum computing is more challenging, although the solution to this problem has been known for some time. Qubits are incredibly delicate since one must control the precise quantum states of single atoms, which are prone to errors. Additionally, we must abide by a fundamental law of quantum physics known as the no cloning theorem, which says that you can’t just copy qubits – meaning some of the techniques used in classical error correction are unavailable in quantum machines.
The solution involves entangling groups of physical qubits (thereby creating a logical qubit), storing the relevant quantum information in the entangled state, and, via some complex functions, performing computations with error correction. This process is all done with the sole purpose of creating logical qubit errors lower than the errors at the physical level.
However, implementing quantum error correction requires a significant number of qubit operations. Unless the underlying physical fidelity is good enough, implementing a quantum error correcting code will add more noise to your circuit than it takes away. No matter how clever you are in implementing a code, if your physical fidelity is poor, the error correcting code will only introduce more noise. But, once your physical fidelity is good enough (aka when the physical error rate is “below threshold”), then you will see the error correcting code start to actually help: producing logical errors below the physical errors.
Quantinuum’s fault-tolerance roadmap
Today’s results are an exciting marker on the path to fault-tolerant quantum computing. The focus must and will now shift from quantum computing companies simply stating the number of qubits they have to explaining their connectivity, the underlying quality of the qubits with reference to gate fidelities, and their approach to fault-tolerance.
Our H-Series hardware roadmap has not only focused on scaling qubits, but also developing useable quantum computers that are part of a vertically integrated stack. Our work across the full stack includes major advances at every level, for instance just last month we proved that our qubits could scale when we announced solutions to the wiring problem and the sorting problem. By maintaining higher qubit counts and world class fidelity, our customers and partners are able to advance further and faster in fields such as material science, drug discovery, AI and finance.
In 2025, we will introduce a new H-Series quantum computer, Helios, that takes the very best the H-Series has to offer, improving both physical qubit count and physical fidelity. This will take us and our users below threshold for a wider set of error correcting codes and make that device capable of supporting at least 10 highly reliable logical qubits.
A path to real-world impact
As we build upon today’s milestone and lead the field on the path to fault-tolerance, we are committed to continuing to make significant strides in the research that enables the rapid advance of our technologies. We were the first to demonstrate real-time quantum error correction (meaning a fully-fault tolerant QEC protocol), a result that meant we were the first to show: repeated real-time error correction, the ability to perform quantum "loops" (repeat-until-success protocols), and real-time decoding to determine the corrections during the computation. We were the first to create non-Abelian topological quantum matter and braid its anyons, leading to topological qubits.
The native flexibility of our QCCD architecture has allowed us to efficiently investigate a large variety of fault-tolerant methods, and our best-in-class fidelity means we expect to lead the way in achieving reduced error rates with additional error correcting codes – and supporting our partners to do the same. We are already working on making reliable quantum computing a commercial reality so that our customers and partners can unlock the enormous real-world economic value that is waiting to be unleashed by the development of these systems.
In the short term – with a hybrid supercomputer powered by a hundred reliable logical qubits, we believe that organizations will be able to start to see scientific advantages and will be able to accelerate valuable progress toward some of the most important problems that mankind faces such as modelling the materials used in batteries and hydrogen fuel cells or accelerating the development of meaning-aware AI language models. Over the long-term, if we are able to scale closer to ~1,000 reliable logical qubits, we will be able to unlock the commercial advantages that can ultimately transform the commercial world.
Quantinuum customers have always been able to operate the most cutting-edge quantum computing, and we look forward to seeing how they, and our own world-leading teams, drive ahead developing new solutions based on the state-of-the-art tools we continue to put into their hands. We were the early leaders in quantum computing and now we are thrilled to be positioned at the forefront of fault-tolerant quantum computing. We are excited to see what today’s milestone unlocks for our customers in the days ahead.
For more information
- Please register for Microsoft’s upcoming Quantum Innovator Series with Quantinuum
- Visit Quantinuum InQuanto to explore this state-of-the-art chemistry platform that will soon offer reliable logical qubits
- Read Microsoft’s announcement
- See System Model H1 and H2 integrated on Azure Quantum
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.
Quantinuum and NVIDIA, world leaders in their respective sectors, are combining forces to fast-track commercially scalable quantum supercomputers, further bolstering the announcement Quantinuum made earlier this year about the exciting new potential in Generative Quantum AI.
Make no mistake about it, the global quantum race is on. With over $2 billion raised by companies in 2024 alone, and over 150 new startups in the past five years, quantum computing is no longer restricted to ‘the lab’.
The United Nations proclaimed 2025 as the International Year of Quantum Science and Technology (IYQ), and as we march toward the end of the first quarter, the old maxim that quantum computing is still a decade (or two, or three) away is no longer relevant in today’s world. Governments, commercial enterprises and scientific organizations all stand to benefit from quantum computers, led by those built by Quantinuum.
That is because, amid the flurry of headlines and social media chatter filled with aspirational statements of future ambitions shared by those in the heat of this race, we at Quantinuum continue to lead by example. We demonstrate what that future looks like today, rather than relying solely on slide deck presentations.
Our quantum computers are the most powerful systems in the world. Our H2 system, the only quantum computer that cannot be classically simulated, is years ahead of any other system being developed today. In the coming months, we’ll introduce our customers to Helios, a trillion times more powerful than H2, further extending our lead beyond where the competition is still only planning to be.
At Quantinuum, we have been convinced for years that the impact of quantum computers on the real world will happen earlier than anticipated. However, we have known that impact will be when powerful quantum computers and powerful classical systems work together.
This sort of hybrid ‘supercomputer’ has been referenced a few times in the past few months, and there is, rightly, a sense of excitement about what such an accelerated quantum supercomputer could achieve.
The Power of Hybrid Quantum and Classical Compute
In a revolutionary move on March 18th, 2025, at the GTC AI conference, NVIDIA announced the opening of a world-class accelerated quantum research center with Quantinuum selected as a key founding collaborator to work on projects with NVIDIA at the center.
With details shared in an accompanying press statement and blog post, the NVIDIA Accelerated Quantum Research Center (NVAQC) being built in Boston, Massachusetts, will integrate quantum computers with AI supercomputers to ultimately explore how to build accelerated quantum supercomputers capable of solving some of the world’s most challenging problems. The center will begin operations later this year.
As shared in Quantinuum’s accompanying statement, the center will draw on the NVIDIA CUDA-Q platform, alongside a NVIDIA GB200 NVL72 system containing 576 NVIDIA Blackwell GPUs dedicated to quantum research.
The Role of CUDA-Q in Quantum-Classical Integration
Integrating quantum and classical hardware relies on a platform that can allow researchers and developers to quickly shift context between these two disparate computing paradigms within a single application. NVIDIA CUDA-Q platform will be the entry-point for researchers to exploit the NVAQC quantum-classical integration.
In 2022, Quantinuum became the first company to bring CUDA-Q to its quantum systems, establishing a pioneering collaboration that continues to today. Users of CUDA-Q are currently offered access to Quantinuum’s System H1 QPU and emulator for 90 days.
Quantinuum’s future systems will continue to support the CUDA-Q platform. Furthermore, Quantinuum and NVIDIA are committed to evolving and improving tools for quantum classical integration to take advantage of the latest hardware features, for example, on our upcoming Helios generation.
The Gen-Q-AI Moment
A few weeks ago, we disclosed high level details about an AI system that we refer to as Generative Quantum AI, or GenQAI. We highlighted a timeline between now and the end of this year when the first commercial systems that can accelerate both existing AI and quantum computers.
At a high level, an AI system such as GenQAI will be enhanced by access to information that has not previously been accessible. Information that is generated from a quantum computer that cannot be simulated. This information and its effect can be likened to a powerful microscope that brings accuracy and detail to already powerful LLM’s, bridging the gap from today’s impressive accomplishments towards truly impactful outcomes in areas such as biology and healthcare, material discovery and optimization.
Through the integration of the most powerful in quantum and classical systems, and by enabling tighter integration of AI with quantum computing, the NVAQC will be an enabler for the realization of the accelerated quantum supercomputer needed for GenQAI products and their rapid deployment and exploitation.
Innovating our Roadmap
The NVAQC will foster the tools and innovations needed for fully fault-tolerant quantum computing and will be enabler to the roadmap Quantinuum released last year.
With each new generation of our quantum computing hardware and accompanying stack, we continue to scale compute capabilities through more powerful hardware and advanced features, accelerating the timeline for practical applications. To achieve these advances, we integrate the best CPU and GPU technologies alongside our quantum innovations. Our long-standing collaboration with NVIDIA drives these advancements forward and will be further enriched by the NVAQC.
Here are a couple of examples:
In quantum error correction, error syndromes detected by measuring "ancilla" qubits are sent to a "decoder." The decoder analyzes this information to determine if any corrections are needed. These complex algorithms must be processed quickly and with low latency, requiring advanced CPU and GPU power to calculate and apply corrections keeping logical qubits error-free. Quantinuum has been collaborating with NVIDIA on the development of customized GPU-based decoders which can be coupled with our upcoming Helios system.
In our application space, we recently announced the integration of InQuanto v4.0, the latest version of Quantinuum’s cutting edge computational chemistry platform, with NVIDIA cuQuantum SDK to enable previously inaccessible tensor-network-based methods for large-scale and high-precision quantum chemistry simulations.
Our work with NVIDIA underscores the partnership between quantum computers and classical processors to maximize the speed toward scaled quantum computers. These systems offer error-corrected qubits for operations that accelerate scientific discovery across a wide range of fields, including drug discovery and delivery, financial market applications, and essential condensed matter physics, such as high-temperature superconductivity.
We look forward to sharing details with our partners and bringing meaningful scientific discovery to generate economic growth and sustainable development for all of humankind.
In the rapidly advancing world of quantum computing, to be a leader means not just keeping pace with innovation but driving it forward. It means setting new standards that shape the future of quantum computing performance. A recent independent study comparing 19 quantum processing units (QPUs) on the market today has validated what we’ve long known to be true: Quantinuum’s systems are the undisputed leaders in performance.
The Benchmarking Study
A comprehensive study conducted by a joint team from the Jülich Supercomputing Centre, AIDAS, RWTH Aachen University, and Purdue University compared QPUs from leading companies like IBM, Rigetti, and IonQ, evaluating how well each executed the Quantum Approximate Optimization Algorithm (QAOA), a widely used algorithm that provides a system level measure of performance. After thorough examination, the study concluded that:
“...the performance of quantinuum H1-1 and H2-1 is superior to that of the other QPUs.”
Quantinuum emerged as the clear leader, particularly in full connectivity, the most critical category for solving real-world optimization problems. Full connectivity is a huge comparative advantage, offering more computational power and more flexibility in both error correction and algorithmic design. Our dominance in full connectivity—unattainable for platforms with natively limited connectivity—underscores why we are the partner of choice in quantum computing.
Leading Across the Board
We take benchmarking seriously at Quantinuum. We lead in nearly every industry benchmark, from best-in-class gate fidelities to a 4000x lead in quantum volume, delivering top performance to our customers.
Our Quantum Charged-coupled Device (QCCD) architecture has been the foundation of our success, delivering consistent performance gains year-over-year. Unlike other architectures, QCCD offers all-to-all connectivity, world-record fidelities, and advanced features like real-time decoding. Altogether, it’s clear we have superior performance metrics across the board.
While many claim to be the best, we have the data to prove it. This table breaks down industry benchmarks, using the leading commercial spec for each quantum computing architecture.
These metrics are the key to our success. They demonstrate why Quantinuum is the only company delivering meaningful results to customers at a scale beyond classical simulation limits.
Our progress builds upon a series of Quantinuum’s technology breakthroughs, including the creation of the most reliable and highest-quality logical qubits, as well as solving the key scalability challenge associated with ion-trap quantum computers — culminating in a commercial system with greater than 99.9% two-qubit gate fidelity.
From our groundbreaking progress with System Model H2 to advances in quantum teleportation and solving the wiring problem, we’re taking major steps to tackle the challenges our whole industry faces, like execution speed and circuit depth. Advancements in parallel gate execution, faster ion transport, and high-rate quantum error correction (QEC) are just a few ways we’re maintaining our lead far ahead of the competition.
This commitment to excellence ensures that we not only meet but exceed expectations, setting the bar for reliability, innovation, and transformative quantum solutions.
Onward and Upward
To bring it back to the opening message: to be a leader means not just keeping pace with innovation but driving it forward. It means setting new standards that shape the future of quantum computing performance.
We are just months away from launching Quantinuum’s next generation system, Helios, which will be one trillion times more powerful than H2. By 2027, Quantinuum will launch the industry’s first 100-logical-qubit system, featuring best-in-class error rates, and we are on track to deliver fault-tolerant computation on hundreds of logical qubits by the end of the decade.
The evidence speaks for itself: Quantinuum is setting the standard in quantum computing. Our unrivaled specs, proven performance, and commitment to innovation make us the partner of choice for those serious about unlocking value with quantum computing. Quantinuum is committed to doing the hard work required to continue setting the standard and delivering on our promises. This is Quantinuum. This is leadership.
Dr. Chris Langer is a Fellow, a key inventor and architect for the Quantinuum hardware, and serves as an advisor to the CEO.
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Citations from Benchmarking Table
1 Quantinuum. System Model H2. Quantinuum, https://www.quantinuum.com/products-solutions/quantinuum-systems/system-model-h2
2 IBM. Quantum Services & Resources. IBM Quantum, https://quantum.ibm.com/services/resources
3 Quantinuum. System Model H1. Quantinuum, https://www.quantinuum.com/products-solutions/quantinuum-systems/system-model-h1
4 Google Quantum AI. Willow Spec Sheet. Google, https://quantumai.google/static/site-assets/downloads/willow-spec-sheet.pdf
5 Sales Rodriguez, P., et al. "Experimental demonstration of logical magic state distillation." arXiv, 19 Dec 2024, https://arxiv.org/pdf/2412.15165
6 Quantinuum. H1 Product Data Sheet. Quantinuum, https://docs.quantinuum.com/systems/data_sheets/Quantinuum%20H1%20Product%20Data%20Sheet.pdf
7 Google Quantum AI. Willow Spec Sheet. Google, https://quantumai.google/static/site-assets/downloads/willow-spec-sheet.pdf
8 Sales Rodriguez, P., et al. "Experimental demonstration of logical magic state distillation." arXiv, 19 Dec 2024, https://arxiv.org/pdf/2412.15165
9 Quantinuum. H2 Product Data Sheet. Quantinuum, https://docs.quantinuum.com/systems/data_sQuantinuum. H2 Product Data Sheet. Quantinuum,heets/Quantinuum%20H2%20Product%20Data%20Sheet.pdf
10 Google Quantum AI. Willow Spec Sheet. Google, https://quantumai.google/static/site-assets/downloads/willow-spec-sheet.pdf
11 Sales Rodriguez, P., et al. "Experimental demonstration of logical magic state distillation." arXiv, 19 Dec 2024, https://arxiv.org/pdf/2412.15165
12 Moses, S. A., et al. "A Race-Track Trapped-Ion Quantum Processor." Physical Review X, vol. 13, no. 4, 2023, https://journals.aps.org/prx/pdf/10.1103/PhysRevX.13.041052
13 Google Quantum AI and Collaborators. "Quantum Error Correction Below the Surface Code Threshold." Nature, vol. 638, 2024, https://www.nature.com/articles/s41586-024-08449-y
14 Bluvstein, Dolev, et al. "Logical Quantum Processor Based on Reconfigurable Atom Arrays." Nature, vol. 626, 2023, https://www.nature.com/articles/s41586-023-06927-3
15 DeCross, Matthew, et al. "The Computational Power of Random Quantum Circuits in Arbitrary Geometries." arXiv, Published on 21 June 2024, hhttps://arxiv.org/pdf/2406.02501
16 Montanez-Barrera, J. A., et al. "Evaluating the Performance of Quantum Process Units at Large Width and Depth." arXiv, 10 Feb. 2025, https://arxiv.org/pdf/2502.06471
17 Evered, Simon J., et al. "High-Fidelity Parallel Entangling Gates on a Neutral-Atom Quantum Computer." Nature, vol. 622, 2023, https://www.nature.com/articles/s41586-023-06481-y
18 Ryan-Anderson, C., et al. "Realization of Real-Time Fault-Tolerant Quantum Error Correction." Physical Review X, vol. 11, no. 4, 2021, https://journals.aps.org/prx/abstract/10.1103/PhysRevX.11.041058
19 Carrera Vazquez, Almudena, et al. "Scaling Quantum Computing with Dynamic Circuits." arXiv, 27 Feb. 2024, https://arxiv.org/html/2402.17833v1
20 Moses, S.A.,, et al. "A Race Track Trapped-Ion Quantum Processor." arXiv, 16 May 2023, https://arxiv.org/pdf/2305.03828
21 Garcia Almeida, D., Ferris, K., Knanazawa, N., Johnson, B., Davis, R. "New fractional gates reduce circuit depth for utility-scale workloads." IBM Quantum Blog, IBM, 18 Nov. 2020, https://www.ibm.com/quantum/blog/fractional-gates
22 Ryan-Anderson, C., et al. "Realization of Real-Time Fault-Tolerant Quantum Error Correction." arXiv, 15 July 2021, https://arxiv.org/pdf/2107.07505
23 Google Quantum AI and Collaborators. “Quantum error correction below the surface code threshold.” arXiv, 24 Aug. 2024, https://arxiv.org/pdf/2408.13687v1
The 2025 Joint March Meeting and April Meeting — referred to as the APS Global Physics Summit — is the largest physics research conference in the world, uniting 14,000 scientific community members across all disciplines of physics.
The Quantinuum team is looking forward to participating in this year’s conference to showcase our latest advancements in quantum technology. Find us throughout the week at the below sessions and visit us at Booth 1001.
Join these sessions to discover how Quantinuum is advancing quantum computing
T11: Quantum Error Correction
Speaker: Natalie Brown
Date: Sunday, March 16th
Time: 8:00 – 8:12am
Location: Anaheim Convention Center, 261B (Level 2)
The computational power of random quantum circuits in arbitrary geometries
Session MAR-F34: Near-Term Quantum Resource Reduction and Random Circuits
Speaker: Matthew DeCross
Date: Tuesday, March 18th
Time: 8:00 – 8:12am
Location: Anaheim Convention Center, 256A (Level 2)
Topological Order from Measurements and Feed-Forward on a Trapped Ion Quantum Computer
Session MAR-F14: Realizing Topological States on Quantum Hardware
Speaker: Henrik Dreyer
Date: Tuesday, March 18th
Time: 9:12 – 9:48am
Location: Anaheim Convention Center, 158 (Level 1)
Trotter error time scaling separation via commutant decomposition
Session MAR-F34: Near-Term Quantum Resource Reduction and Random Circuits
Speaker: Yi-Hsiang Chen (Quantinuum)
Date: Tuesday, March 18th
Time: 10:00 – 10:12am
Location: Anaheim Convention Center, 256A (Level 2)
Squared overlap calculations with linear combination of unitaries
Session MAR-J35: Circuit Optimization and Compilation
Speaker: Michelle Wynne Sze
Date: Tuesday, March 18th
Time: 4:36 – 4:48pm
Location: Anaheim Convention Center, 256B (Level 2)
High-precision quantum phase estimation on a trapped-ion quantum computer
Session MAR-L16: Quantum Simulation for Quantum Chemistry
Speaker: Andrew Tranter
Date: Wednesday, March 19th
Time: 9:48 – 10:00am
Location: Anaheim Convention Center, 160 (Level 1)
Robustness of near-thermal dynamics on digital quantum computers
Session MAR-L16: Quantum Simulation for Quantum Chemistry
Speaker: Eli Chertkov
Date: Wednesday, March 19th
Time: 10:12 – 10:24am
Location: Anaheim Convention Center, 160 (Level 1)
Floquet prethermalization on a digital quantum computer
Session MAR-Q09: Quantum Simulation of Condensed Matter Physics
Speaker: Reza Haghshenas
Date: Thursday, March 20th
Time: 10:00 – 10:12am
Location: Anaheim Convention Center, 204C (Level 2)
Teleportation of a Logical Qubit on a Trapped-ion Quantum Computer
Session MAR-S11: Advances in QEC Experiments
Speaker: Ciaran Ryan-Anderson
Date: Thursday, March 20th
Time: 11:30 – 12:06pm
Location: Anaheim Convention Center, 155 (Level 1)
*All times in Pacific Standard Time