Announcing Quixer – Quantinuum’s State-of-the-Art Quantum Transformer, Making Quantum AI a Little More Realistic
The marriage of AI and quantum computing holds big promise: the computational power of quantum computers could lead to huge breakthroughs in this next-gen tech. A team led by Stephen Clark, our Head of AI, has just helped us move towards unlocking this incredible potential.
A key ingredient in contemporary classical AI is the “transformer”, which is so important it is actually the “T” in ChatGPT. Transformers are machine learning models that do things like predict the next word in a sentence, or determine if a movie review is positive or negative. Transformers are incredibly well-suited to classical computers, taking advantage of the massive parallelism afforded by GPUs. These advantages are not necessarily present on quantum computers in the same way, so successfully implementing a transformer on quantum hardware is no easy task.
Until recently, most attempts to implement transformers on quantum computers took a sort of “copy-paste” approach – taking the math from a classical implementation and directly implementing it on quantum circuits. This “copy-paste” approach fails to account for the considerable differences between quantum and classical architectures, leading to inefficiencies. In fact, they are not really taking advantage of the ‘quantum’ paradigm at all.
This has now changed. In a new paper on the arXiv, our team introduces an explicitly quantum transformer, which they call “Quixer” (short for quantum mixer). Using quantum algorithmic primitives, the team created a transformer implementation that is specially tailored for quantum circuits, making it qubit efficient and providing the potential to offer speedups over classical implementations.
Critically, the team then applied it to a practical language modelling task (by simulating the process on a classical computer), obtaining results that are competitive with an equivalent classical baseline. This is an incredible milestone achievement in and of itself.
This paper also marks the first quantum machine learning model applied to language on a realistic rather than toy dataset. This is a truly exciting advance for anyone interested in the union of quantum computing and artificial intelligence. About a week ago when we announced that our System Model H2 has bested the quantum supremacy experiments first benchmarked by Google, we promised a summer of important advances in quantum computing. Stay tuned for more disclosures!
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 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.
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.
By Bob Coecke and Dimitri Kartsaklis
Introduction
Today we announce the next generation of λambeq , Quantinuum’s quantum natural language processing (QNLP) package.
Incorporating recent developments in both quantum NLP and quantum hardware, λambeq Gen II allows users not only to model the semantics of natural language (in terms of vectors and tensors), but to convert linguistic structures and meaning directly into quantum circuits for real quantum hardware.
Five years ago, our team reported the first realization of Quantum Natural Language Processing (QNLP). In their work, the team realized that there is a direct correspondence between the meanings of words and quantum states, and between grammatical structures and quantum entanglement. As that article put it: “Language is effectively quantum native”.
Our team realized an NLP task on quantum hardware and provided the data and code via a GitHub repository, attracting the interest of a then-nascent quantum NLP community, which has since grown around successive releases of λambeq. We released it 18 months later, supported by a research paper on the arXiv.
Λambeq: an open-source python library that turns sentences into quantum circuits, and then feeds these to quantum computers subject to VQC methodologies. Initial release in October 2021 arXiv:2110.04236
From that moment onwards, anyone could play around with QNLP on the then freely available quantum hardware. Our λambeq software has been downloaded over 50,000 times, and the user community is supported by an active Discord page, where practitioners can interact with each other and with our development team.
The QNLP Back-Story
In order to demonstrate that QNLP was possible, even on the hardware available in 2021, we focused exclusively on small noisy quantum computers. Our motivation was to produce some exploratory findings, looking for a potential quantum advantage for natural language processing using quantum hardware. We published our original scientific work in 2016, detailing a quadratic speedup over classical computers (in certain circumstances). We are strongly convinced that there is a lot more potential than indicated in that paper.
That first realization of QNLP marked a shift away from brute-force machine learning, which has now taken the world by storm in the shape of large language models (LLMs) running on algorithms called “transformers”.
Instead of the transformer approach, we decoded linguistic structure using a compositional theory of meaning. With deep roots in computational linguistics, our approach was inspired by research into compositional linguistic algorithms, and their resemblance to other quantum primitives such as quantum teleportation. As we continued our work, it became clear that our approach reduced training requirements by relying on a natural relationship between linguistic structure and quantum structure, offering near-term QNLP in practice.
Embedding recent progress in λambeq Gen II
We haven’t sat still, and neither have the teams working in the field of quantum hardware. Quantinuum’s stack now performs at a level we only dreamed of in 2020. While we look forward to continued progress on the hardware front, we are getting ahead of these future developments by shifting the focus in our algorithms and software packages, to ensure we and λambeq’s users are ready to chase far more ambitious goals!
We moved away from the compositional theory of meaning that was the focus of our early experiments, called DisCoCat, to a new mathematical foundation called DisCoCirc. This enabled us to explore the relationship between text generation and text circuits, concluding that “text circuits are generative for text”.
Formally speaking, DisCoCirc embraces substantially more compositional structure present in language than DisCoCat does, and that pays off in many ways:
- Firstly, the new theoretical backbone enables one to compose the structure of sentences into text structure, so we can now deal with large texts.
- Secondly, the compositional structure of language is represented in a compressed manner, that, in fact, makes the formalism language-neutral, as reported in this blog post.
- Thirdly, the augmented compositional linguistic structure, together with the requirement of learnability, makes a quantum model now canonical, and we now have solid theoretical evidence for genuine enhanced performance on quantum hardware, as shown in this arXiv paper.
- Fourthly, the problems associated with trainability of quantum machine learning models vanish, thanks to compositional generalization, which was the subject of this paper.
- Lastly, and surely not least, we reported on the achievement of compositional interpretability and explored the myriad ways that it supports explainable AI (XAI), which we also discussed extensively in this blog post.
Today, our users can benefit from these recent developments with the release λambeq Gen II. Our open-source tools have always benefited from the attention and feedback we receive from our users. Please give it a try, and we look forward to hearing your feedback on λambeq Gen II.
Enjoy!
We're announcing the world’s first scalable, error-corrected, end-to-end computational chemistry workflow. With this, we are entering the future of computational chemistry.
Quantum computers are uniquely equipped to perform the complex computations that describe chemical reactions – computations that are so complex they are impossible even with the world’s most powerful supercomputers.
However, realizing this potential is a herculean task: one must first build a large-scale, universal, fully fault-tolerant quantum computer – something nobody in our industry has done yet. We are the farthest along that path, as our roadmap, and our robust body of research, proves. At the moment, we have the world’s most powerful quantum processors, and are moving quickly towards universal fault tolerance. Our commitment to building the best quantum computers is proven again and again in our world-leading results.
While we do the work to build the world’s best quantum computers, we aren’t waiting to develop their applications. We have teams working right now on making sure that we hit the ground running with each new hardware generation. In fact, our team has just taken a huge leap forward for computational chemistry using our System Model H2.
In our latest paper, we have announced the first-ever demonstration of a scalable, end-to-end workflow for simulating chemical systems with quantum error correction (QEC). This milestone shows that quantum computing will play an essential role, in tandem with HPC and AI, in unlocking new frontiers in scientific discovery.
In the paper, we showcase the first practical combination of quantum phase estimation (QPE) with logical qubits for molecular energy calculations – an essential step toward fault-tolerant quantum simulations. It builds on our previous work implementing quantum error detection with QPE and marks a critical step toward achieving quantum advantage in chemistry.
By demonstrating this end-to-end workflow on our H2 quantum computer using our state-of-the-art chemistry platform InQuanto™, we are proving that quantum error-corrected chemistry simulations are not only feasible, but also scalable and —crucially—implementable in our quantum computing stack.
This work sets key benchmarks on the path to fully fault-tolerant quantum simulations. Building such capabilities into an industrial workflow will be a milestone for quantum computing, and the demonstration reported here represents a new high-water mark as we continue to lead the global industry in pushing towards universal fault-tolerant computers capable of widespread scientific and commercial advantage.
As we look ahead, this workflow will serve as the foundation for future quantum-HPC integration, enabling chemistry simulations that are impossible today.
Showcasing Quantinuum’s Full-Stack Advantage
Today’s achievement wouldn’t be possible without the Quantinuum’s full stack approach. Our vertical integration - from hardware to software to applications - ensures that each layer works together seamlessly.
Our H2 quantum computer, based on the scalable QCCD architecture with its unique combination of high-fidelity operations, all-to-all connectivity, mid-circuit measurements and conditional logic, enabled us to run more complex quantum computing simulations than previously possible. The work also leverages Quantinuum’s real-time QEC decoding capability and benefitted from the quantum error correction advantages also provided by QCCD.
We will make this workflow available to customers via InQuanto, our quantum chemistry platform, allowing users to easily replicate and build upon this work. The integration of high-quality quantum computing hardware with sophisticated software creates a robust environment for iterating and accelerating breakthroughs in fields like chemistry and materials science.
A Collaborative Future: The Role of AI and Supercomputing
Achieving quantum advantage in chemistry will require more than just quantum hardware; it will require a synergistic approach that combines such quantum computing workflows demonstrated here with classical supercomputing and AI. Our strategic partnerships with leading supercomputing providers – with Quantinuum being selected as a founding collaborator for NVIDIA’s Accelerated Quantum Research Center – as well as our commitment to exploring generative quantum AI, place us in a unique position to maximize the benefit of quantum computing, and supercharge quantum advantage with the integration of classical supercomputing and AI.
Conclusion
Quantum computing holds immense potential for transforming industries across the globe. Our work today experimentally demonstrates the first complete and scalable quantum chemistry simulation, showing that the long-awaited quantum advantage in simulating chemical systems is not only possible, but within reach. With the development of new error correction techniques and the continued advancement of our quantum hardware and software we are paving the way for a future where quantum simulations can address challenges that are impossible today. Quantinuum’s ongoing collaborations with HPC providers and its exploration of AI-driven quantum techniques position our company to capitalize on this trifecta of computing power and achieve meaningful breakthroughs in quantum chemistry and beyond.
We encourage you to explore this breakthrough further by reading our latest research on arXiv and try out the Python code for yourself.