Quantum Milestone: We Can Now Detect and Correct Quantum Errors in Real Time

Researchers at Honeywell Quantum Solutions applied multiple rounds of quantum error correction to a single logical qubit, an industry first

November 27, 2021

Cambridge Researchers at Honeywell Quantum Solutions have taken a significant step toward demonstrating the viability of large-scale quantum computing on its trapped-ion quantum computing technology. 

The Honeywell team can now perform quantum error correction (QEC), which are protocols necessary to detect and correct errors in real time on a quantum computer. They demonstrated the ability to “protect” quantum information (prevent a quantum computation from being quickly corrupted by imperfections and noise) on the System Model H1. This is an important first in the quantum computing industry. Currently, most demonstrations of quantum error correction involve correcting errors or “noise” after the procedure has finished running, a technique known as post-processing.

In a paper published this week on arXiv, researchers detailed how they created a single logical qubit (a series of entangled physical qubits) and applied multiple rounds of quantum error correction. This logical qubit is protected from two main types of errors that occur in a quantum computer: bit flips and phase flips.

Previously, groups have looked at codes that only are capable of correcting a single type of error (bit or phase but not both) {Google, IBM/Raytheon, IBM/Basel}. Others have looked at quantum error detecting codes, which can detect both types of errors but not correct them {ETH, Google, Delft}. Further still, groups have demonstrated pieces of the quantum error correcting process {Blatt, Monroe}. 

“All of today’s quantum technologies are at an early stage where they must combat errors that accumulate during computations,” said Tony Uttley, president of Honeywell Quantum Solutions. “What the Honeywell team accomplished is groundbreaking. It proves what was once only theoretical, that quantum computers will be able to correct errors in real time, paving the way for precise quantum computations.”

Though the achievement represents progress toward large-scale quantum computing, Honeywell researchers are still working to cross the break-even point at which the logical error rate is less than the physical error rate. 

The need for logical qubits

To appreciate this achievement, it is important to understand how difficult it is to detect and then correct a quantum error.

Quantum bits, or qubits, are fragile and finicky. They pick up interference or “noise” from their environment. This noise causes errors to accumulate and corrupts information stored in and between physical qubits. Scientists call this decoherence.

Attempts to directly detect and correct errors on a physical qubit also corrupts its “quantumness.” And cloning this data, a method used in classical computing that involves making multiple exact copies of the information, does not work in quantum (as prohibited by “The No Cloning Theorem”.)

To overcome these concerns, several scientists, most notably Peter Shor, Robert Calberbank, and Andrew Steane, found a way around this, at least in theory, after studying how quickly qubits experience decoherence.

They demonstrated that by storing information in a collection of entangled qubits, it was possible to detect and correct errors without disrupting quantum information. They called this assortment of entangled qubits a logical qubit. 

Scientists have spent years developing codes and methods that could be applied to logical qubits to protect quantum information from errors.

What’s next

The next step is to break even, crossing the point at which the logical qubit error rate is lower than the error rate for physical qubits. (Creating logical qubits and applying quantum error correction codes also can inject noise into a system).

The Honeywell team is closing in on that mark. To definitively demonstrate passing the break-even point, the error rate per QEC cycle needs to be lower than the largest physical error rate associated with the QEC protocol. 

“In the technical paper, we point to key improvements we need to make to reach the break-even point,” said Dr. Ciaran Ryan-Anderson, an advanced physicist and lead author of the paper. “We believe these improvements are feasible and are pushing to accomplish this next step.”

From there, the goal is to create multiple logical qubits, which depending on the quantum technology, requires better fidelities, more physical qubits, better connectivity between qubits, and other factors.

An increase in logical qubits will usher in a new era of fault-tolerant quantum computers that can continue to function even when some operations fail. (Fault tolerance is a design principle that prevents errors from cascading throughout a system and corrupting circuits.)

“The big, enterprise-level problems we want to solve with quantum computers require precision and we need error-corrected logical qubits to scale successfully,” Uttley said.

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. 

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June 10, 2025
Our Hardware is Now Running Quantum Transformers!

If we are to create ‘next-gen’ AI that takes full advantage of the power of quantum computers, we need to start with quantum native transformers. Today we announce yet again that Quantinuum continues to lead by demonstrating concrete progress — advancing from theoretical models to real quantum deployment.

The future of AI won't be built on yesterday’s tech. If we're serious about creating next-generation AI that unlocks the full promise of quantum computing, then we must build quantum-native models—designed for quantum, from the ground up.

Around this time last year, we introduced Quixer, a state-of-the-art quantum-native transformer. Today, we’re thrilled to announce a major milestone: one year on, Quixer is now running natively on quantum hardware.

Why this matters: Quantum AI, born native

This marks a turning point for the industry: realizing quantum-native AI opens a world of possibilities.

Classical transformers revolutionized AI. They power everything from ChatGPT to real-time translation, computer vision, drug discovery, and algorithmic trading. Now, Quixer sets the stage for a similar leap — but for quantum-native computation. Because quantum computers differ fundamentally from classical computers, we expect a whole new host of valuable applications to emerge.  

Achieving that future requires models that are efficient, scalable, and actually run on today’s quantum hardware.

That’s what we’ve built.

What makes Quixer different?

Until Quixer, quantum transformers were the result of a brute force “copy-paste” approach: taking the math from a classical model and putting it onto a quantum circuit. However, this approach does not account for the considerable differences between quantum and classical architectures, leading to substantial resource requirements.

Quixer is different: it’s not a translation – it's an innovation.

With Quixer, our team introduced an explicitly quantum transformer, built from the ground up using quantum algorithmic primitives. Because Quixer is tailored for quantum circuits, it's more resource efficient than most competing approaches.

As quantum computing advances toward fault tolerance, Quixer is built to scale with it.

What’s next for Quixer?

We’ve already deployed Quixer on real-world data: genomic sequence analysis, a high-impact classification task in biotech. We're happy to report that its performance is already approaching that of classical models, even in this first implementation.

This is just the beginning.

Looking ahead, we’ll explore using Quixer anywhere classical transformers have proven to be useful; such as language modeling, image classification, quantum chemistry, and beyond. More excitingly, we expect use cases to emerge that are quantum-specific, impossible on classical hardware.

This milestone isn’t just about one model. It’s a signal that the quantum AI era has begun, and that Quantinuum is leading the charge with real results, not empty hype.

Stay tuned. The revolution is only getting started.

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June 9, 2025
Join us at ISC25

Our team is participating in ISC High Performance 2025 (ISC 2025) from June 10-13 in Hamburg, Germany!

As quantum computing accelerates, so does the urgency to integrate its capabilities into today’s high-performance computing (HPC) and AI environments. At ISC 2025, meet the Quantinuum team to learn how the highest performing quantum systems on the market, combined with advanced software and powerful collaborations, are helping organizations take the next step in their compute strategy.

Quantinuum is leading the industry across every major vector: performance, hybrid integration, scientific innovation, global collaboration and ease of access.

  • Our industry-leading quantum computer holds the record for performance with a Quantum Volume of 2²³ = 8,388,608 and the highest fidelity on a commercially available QPU available to our users every time they access our systems.
  • Our systems have been validated by a #1 ranking against competitors in a recent benchmarking study by Jülich Research Centre.
  • We’ve laid out a clear roadmap to reach universal, fully fault-tolerant quantum computing by the end of the decade and will launch our next-generation system, Helios, later this year.
  • We are advancing real-world hybrid compute with partners such as RIKEN, NVIDIA, SoftBank, STFC Hartree Center and are pioneering applications such as our own GenQAI framework.
Exhibit Hall

From June 10–13, in Hamburg, Germany, visit us at Booth B40 in the Exhibition Hall or attend one of our technical talks to explore how our quantum technologies are pushing the boundaries of what’s possible across HPC.

Presentations & Demos

Throughout ISC, our team will present on the most important topics in HPC and quantum computing integration—from near-term hybrid use cases to hardware innovations and future roadmaps.

Multicore World Networking Event

  • Monday, June 9 | 7:00pm – 9:00 PM at Hofbräu Wirtshaus Esplanade
    In partnership with Multicore World, join us for a Quantinuum-sponsored Happy Hour to explore the present and future of quantum computing with Quantinuum CCO, Dr. Nash Palaniswamy, and network with our team.
    Register here

H1 x CUDA-Q Demonstration

  • All Week at Booth B40
    We’re showcasing a live demonstration of NVIDIA’s CUDA-Q platform running on Quantinuum’s industry-leading quantum hardware. This new integration paves the way for hybrid compute solutions in optimization, AI, and chemistry.
    Register for a demo

HPC Solutions Forum

  • Wednesday, June 11 | 2:20 – 2:40 PM
    “Enabling Scientific Discovery with Generative Quantum AI” – Presented by Maud Einhorn, Technical Account Executive at Quantinuum, discover how hybrid quantum-classical workflows are powering novel use cases in scientific discovery.
See You There!

Whether you're exploring hybrid solutions today or planning for large-scale quantum deployment tomorrow, ISC 2025 is the place to begin the conversation.

We look forward to seeing you in Hamburg!

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May 27, 2025
Teleporting to new heights

Quantinuum has once again raised the bar—setting a record in teleportation, and advancing our leadership in the race toward universal fault-tolerant quantum computing.

Last year, we published a paper in Science demonstrating the first-ever fault-tolerant teleportation of a logical qubit. At the time, we outlined how crucial teleportation is to realize large-scale fault tolerant quantum computers. Given the high degree of system performance and capabilities required to run the protocol (e.g., multiple qubits, high-fidelity state-preparation, entangling operations, mid-circuit measurement, etc.), teleportation is recognized as an excellent measure of system maturity.

Today we’re building on last year’s breakthrough, having recently achieved a record logical teleportation fidelity of 99.82% – up from 97.5% in last year’s result. What’s more, our logical qubit teleportation fidelity now exceeds our physical qubit teleportation fidelity, passing the break-even point that establishes our H2 system as the gold standard for complex quantum operations.

Figure 1: Fidelity of two-bit state teleportation for physical qubit experiments and logical qubit experiments using the d=3 color code (Steane code). The same QASM programs that were ran during March 2024 on the Quantinuum's H2-1 device were reran on the same device on April to March 2025. Thanks to the improvements made to H2-1 from 2024 to 2025, physical error rates have been reduced leading to increased fidelity for both the physical and logical level teleportation experiments. The results imply a logical error rate that is 2.3 times smaller than the physical error rate while being statistically well separated, thus indicating the logical fidelities are below break-even for teleportation.

This progress reflects the strength and flexibility of our Quantum Charge Coupled Device (QCCD) architecture. The native high fidelity of our QCCD architecture enables us to perform highly complex demonstrations like this that nobody else has yet to match. Further, our ability to perform conditional logic and real-time decoding was crucial for implementing the Steane error correction code used in this work, and our all-to-all connectivity was essential for performing the high-fidelity transversal gates that drove the protocol.

Teleportation schemes like this allow us to “trade space for time,” meaning that we can do quantum error correction more quickly, reducing our time to solution. Additionally, teleportation enables long-range communication during logical computation, which translates to higher connectivity in logical algorithms, improving computational power.

This demonstration underscores our ongoing commitment to reducing logical error rates, which is critical for realizing the promise of quantum computing. Quantinuum continues to lead in quantum hardware performance, algorithms, and error correction—and we’ll extend our leadership come the launch of our next generation system, Helios, in just a matter of months.

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