Built for All: Introducing Our New Software Stack
Our next-generation quantum computer, Helios, will come online this year as more than a new chip. It will arrive as a full-stack platform that sets a new standard for the industry.
With our current and previous generation systems, H2 and H1, we have set industry records for the highest fidelities, pioneered the teleportation of logical qubits, and introduced the world’s first commercial application for quantum computers. Much of this success stems from the deep integration between our software and hardware.
Today, we are excited to share the details of our new software stack. Its features and benefits, outlined below, enable a lower barrier to entry, faster time-to-solution, industry-standard access, and the best possible user experience on Helios.
Most importantly, this stack is designed with the future in mind as Quantinuum advances toward universal, fully fault-tolerant quantum computing.
Watch the technical webinar on our new software stack
Our Next-Generation Software Stack: What’s New
Our Current Generation Software Stack
Currently, the solutions our customers explore on our quantum hardware, which span cybersecurity, quantum chemistry, and quantum AI, plus third-party programs, are all powered by two middleware technologies:
- TKET, an open-source tool kit used by developers to build quantum software programs; and
- Nexus, a cloud-based SaaS platform, is the pathway to access our hardware, as well as third-party hardware. Nexus is our all-in-one computing platform, the entry point to everything quantum.
Our Next Generation Software Stack
The launch of Helios will come with an upgraded software stack with new features. We’re introducing two key additions to the stack, specifically:
- Guppy, a new, open-source programming language based on Python, one of the most popular general-use programming languages for classical computing; and
- Selene, a platform that partially emulates Helios, is used to perform program analysis and verification. Selene can be seen almost as a “digital sister” for Helios.
Moving forward, users will now leverage Guppy to run software applications on Helios and our future systems. TKET will be used solely as a compiler tool chain and for the optimization of Guppy programs.
Nexus, which remains as the default pathway to access our hardware, and third-party hardware, has been upgraded to support Guppy and provide access to Selene. Nexus also supports Quantum Intermediate Representation (QIR), an industry standard, which enables developers to program with languages like NVIDIA CUDA-Q, ensuring our stack stays accessible to the whole ecosystem.
With this new stack running on our next generation Helios system, several benefits will be delivered to the end user, including, but not limited to, improved time-to-solution and reduced memory error for programs critical to quantum error correction and utility-scale algorithms.
Below, we dive deeper into these upgrades and what they mean for our customers.
Introducing Guppy: A Purpose-Built Language for Quantum Programming
Designed for the Next Era of Quantum Computing
Guppy is a new programming language hosted in Python, providing developers with a familiar, accessible entry point into the next era of quantum computing.
As Quantinuum leads the transition from the noisy intermediate scale quantum (NISQ) era to fault-tolerant quantum computing, Guppy represents a fundamental departure from legacy circuit-building tools. Instead of forcing developers to construct programs gate-by-gate, a tedious and error-prone process, Guppy treats quantum programs as structured, dynamic software.
With native support for real-time feedback and common programming constructs like ‘if’ statements and ‘for’loops, Guppy enables developers to write complex, readable programs that adapt as the quantum system evolves. This approach unlocks unprecedented power and clarity, far surpassing traditional tools.
Designed with fault-tolerance in mind, Guppy also optimizes qubit resource management automatically, improving efficiency and reducing developer overhead.
All Guppy programs can be seamlessly submitted and managed through Nexus, our all-in-one quantum computing platform.
Find out more at guppylang.org
The Most Flexible Approach to Quantum Error Correction
When it comes to quantum error correction (QEC), flexibility is everything. That is why we designed Guppy to reduce barriers to entry to access necessary features for QEC.
Unlike platforms locked into rigid, hardware-specific codes, Quantinuum’s QCCD architecture gives developers the freedom to implement any QEC code. In a rapidly evolving field, this adaptability is critical: the ability to test and deploy the latest techniques can mean the difference between achieving quantum advantage and falling behind.
With Guppy, developers can implement advanced protocols such as magic state distillation and injection, quantum teleportation, and other measurement-based routines, all executed dynamically through our real-time control system. This creates an environment where researchers can push the limits of fault-tolerance now—not years from now.
In addition, users can employ NVIDIA’s CUDA-QX for out-of-the-box QEC, without needing to worry about writing their own decoders, simplifying the development of novel QEC codes.
By enabling a modular, programmable approach to QEC, our stack accelerates the path to fault-tolerance and positions us to scale quickly as more efficient codes emerge from the research frontier.
Real-Time Control for True Quantum Computing
Integrated seamlessly with Guppy is a next-generation control system powered by a new real-time engine, a key breakthrough for large-scale quantum computing.
This control layer makes our software stack the first commercial system to deliver full measurement-dependent control with undefined sequence length. In practical terms, that means operations can now be guided dynamically by quantum measurements as they occur—a critical step toward truly adaptive, fault-tolerant algorithms.
At the hardware level, features like real-time transport enable dynamic software capabilities, such as conditionals, loops, and recursion, which are all foundational for scaling from thousands to millions of qubits.
These advances deliver tangible performance gains, including faster time-to-solution, reduced memory error, and greater algorithmic efficiency, providing the foundational support required to convert algorithmic advances into useful real-world applications.
Meet Selene: A “Digital Sister” for Helios and Beyond
Quantum hardware access is limited, but development shouldn't be. Selene is our new open-source emulator, built to model realistic, entangled quantum behavior with exceptional detail and speed.
Unlike generic simulators, Selene captures advanced runtime behavior unique to Helios, including measurement-dependent control flow and hybrid quantum-classical logic. It runs Guppy programs out of the box, allowing developers to start building and testing immediately without waiting for machine time.
Selene supports multiple simulation backends, giving users state-of-the-art options for their specific needs, including backends optimized for matrix product state and tensor network simulations using NVIDIA GPUs and cuQuantum. This ensures maximum performance both on the quantum processor and in simulation.
Nexus: Bringing It All Together
These new features, and more, are available through Nexus, our all-in-one quantum computing platform.
Nexus serves as the middle layer that connects every part of the stack, providing a cloud-native SaaS environment for full-stack workflows, including server-side Selene instances. Users can manage Guppy programs, analyze results, and collaborate with others, all within a single, streamlined platform.
Further, Selene users who submit quantum state-vector simulations—the most complete and powerful method to simulate a general quantum circuit on a classical computer—through Nexus will be leveraging the NVIDIA cuQuantum library for efficient GPU-powered simulation.
Bringing Us All Together
Our entire stack, including Nexus and Selene, supports the industry-standard Quantum Intermediate Representation (QIR) as input, allowing users to program in their preferred programming language. QIR provides a common format for accessing a range of quantum computing backends, and Quantinuum Helios will support the full Adaptive Profile QIR This means developers can generate programs for Helios using tools like NVIDIA CUDA-Q, Microsoft Q#, and ORNL XACC.
Always Looking Forward
Our customers choose Quantinuum as their top quantum computing partner because no one else matches our team or our results. We remain the leaders in quantum computing and the only provider of integrated quantum resources that will address our society’s most complex problems.
That future is already taking shape. With Helios and our new software stack, we are building the foundation for scalable, programmable, real-time quantum computing.
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 is focusing on redefining what’s possible in hybrid quantum–classical computing by integrating Quantinuum’s best-in-class systems with high-performance NVIDIA accelerated computing to create powerful new architectures that can solve the world’s most pressing challenges.
The launch of Helios, Powered by Honeywell, the world’s most accurate quantum computer, marks a major milestone in quantum computing. Helios is now available to all customers through the cloud or on-premise deployment, launched with a go-to-market offering that seamlessly pairs Helios with the NVIDIA Grace Blackwell platform, targeting specific end markets such as drug discovery, finance, materials science, and advanced AI research.
We are also working with NVIDIA to adopt NVIDIA NVQLink, an open system architecture, as a standard for advancing hybrid quantum-classical supercomputing. Using this technology with Quantinuum Guppy and the NVIDIA CUDA-Q platform, Quantinuum has implemented NVIDIA accelerated computing across Helios and future systems to perform real-time decoding for quantum error correction.
In an industry-first demonstration, an NVIDIA GPU-based decoder integrated in the Helios control engine improved the logical fidelity of quantum operations by more than 3% — a notable gain given Helios’ already exceptionally low error rate. These results demonstrate how integration with NVIDIA accelerated computing through NVQLink can directly enhance the accuracy and scalability of quantum computation.
This unique collaboration spans the full Quantinuum technology stack. Quantinuum’s next-generation software development environment allows users to interleave quantum and GPU-accelerated classical computations in a single workflow. Developers can build hybrid applications using tools such as NVIDIA CUDA-Q, NVIDIA CUDA-QX, and Quantinuum’s Guppy, to make advanced quantum programming accessible to a broad community of innovators.
The collaboration also reaches into applied research through the NVIDIA Accelerated Quantum Computing Research Center (NVAQC), where an NVIDIA GB200 NVL72 supercomputer can be paired with Quantinuum’s Helios to further drive hybrid quantum-GPU research, including the development of breakthrough quantum-enhanced AI applications.
A recent achievement illustrates this potential: The ADAPT-GQE framework, a transformer-based Generative Quantum AI (GenQAI) approach, uses a Generative AI model to efficiently synthesize circuits to prepare the ground state of a chemical system on a quantum computer. Developed by Quantinuum, NVIDIA, and a pharmaceutical industry leader—and leveraging NVIDIA CUDA-Q with GPU-accelerated methods—ADAPT-GQE achieved a 234x speed-up in generating training data for complex molecules. The team used the framework to explore imipramine, a molecule crucial to pharmaceutical development. The transformer was trained on imipramine conformers to synthesize ground state circuits at orders of magnitude faster than ADAPT-VQE, and the circuit produced by the transformer was run on Helios to prepare the ground state using InQuanto, Quantinuum's computational chemistry platform.
From collaborating on hardware and software integrations to GenQAI applications, the collaboration between Quantinuum and NVIDIA is building the bridge between classical and quantum computing and creating a future where AI becomes more expansive through quantum computing, and quantum computing becomes more powerful through AI.
By Dr. Noah Berthusen
The earliest works on quantum error correction showed that by combining many noisy physical qubits into a complex entangled state called a "logical qubit," this state could survive for arbitrarily long times. QEC researchers devote much effort to hunt for codes that function well as "quantum memories," as they are called. Many promising code families have been found, but this is only half of the story.
Being able to keep a qubit around for a long time is one thing, but to realize the theoretical advantages of quantum computing we need to run quantum circuits. And to make sure noise doesn't ruin our computation, these circuits need to be run on the logical qubits of our code. This is often much more challenging than performing gates on the physical qubits of our device, as these "logical gates" often require many physical operations in their implementation. What's more, it often is not immediately obvious which logical gates a code has, and so converting a physical circuit into a logical circuit can be rather difficult.
Some codes, like the famous surface code, are good quantum memories and also have easy logical gates. The drawback is that the ratio of physical qubits to logical qubits (the "encoding rate") is low, and so many physical qubits are required to implement large logical algorithms. High-rate codes that are good quantum memories have also been found, but computing on them is much more difficult. The holy grail of QEC, so to speak, would be a high-rate code that is a good quantum memory and also has easy logical gates. Here, we make progress on that front by developing a new code with those properties.
Building on prior error correcting codes
A recent work from Quantinuum QEC researchers introduced genon codes. The underlying construction method for these codes, called the "symplectic double cover," also provided a way to obtain logical gates that are well suited for Quantinuum's QCCD architecture. Namely, these "SWAP-transversal" gates are performed by applying single qubit operations and relabeling the physical qubits of the device. Thanks to the all-to-all connectivity facilitated through qubit movement on the QCCD architecture, this relabeling can be done in software essentially for free. Combined with extremely high fidelity (~1.2 x10-5) single-qubit operations, the resulting logical gates are similarly high fidelity.
Given the promise of these codes, we take them a step further in our new paper. We combine the symplectic double codes with the [[4,2,2]] Iceberg code using a procedure called "code concatenation". A concatenated code is a bit like nesting dolls, with an outer code containing codes within it---with these too potentially containing codes. More technically, in a concatenated code the logical qubits of one code act as the physical qubits of another code.
The new codes, which we call "concatenated symplectic double codes", were designed in such a way that they have many of these easily-implementable SWAP-transversal gates. Central to its construction, we show how the concatenation method allows us to "upgrade" logical gates in terms of their ease of implementation; this procedure may provide insights for constructing other codes with convenient logical gates. Notably, the SWAP-transversal gate set on this code is so powerful that only two additional operations (logical T and S) are necessary for universal computation. Furthermore, these codes have many logical qubits, and we also present numerical evidence to suggest that they are good quantum memories.
Concatenated symplectic double codes have one of the easiest logical computation schemes, and we didn’t have to sacrifice rate to achieve it. Looking forward in our roadmap, we are targeting hundreds of logical qubits at ~ 1x 10-8 logical error rate by 2029. These codes put us in a prime position to leverage the best characteristics of our hardware and create a device that can achieve real commercial advantage.
Every year, the International Conference for High Performance Computing, Networking, Storage, and Analysis (SC) brings together the global supercomputing community to explore the technologies driving the future of computing.
Join Quantinuum at this year’s conference, taking place November 16th – 21st in St. Louis, Missouri, where we will showcase how our quantum hardware, software, and partnerships are helping define the next era of high-performance and quantum computing.
Visit Quantinuum in the Expo Hall
The Quantinuum team will be on-site at booth #4432 to showcase how we’re building the bridge between HPC and quantum.
- Live demo unit of our quantum hardware
- Our new Helios replica, providing an up-close look at the design behind our next-generation system
- The Helios chip, highlighting the innovation driving the world’s most advanced trapped-ion quantum computers
On Tuesday and Wednesday, our quantum computing experts will host daily tutorials at our booth on Helios, our next-generation hardware platform, Nexus, our all-in-one quantum computing platform, and Hybrid Workflows, featuring the integration of NVIDIA CUDA-Q with Quantinuum Systems.
Speaking Sessions at SC25
Join our team as they share insights on the opportunities and challenges of quantum integration within the HPC ecosystem:
Panel Session: The Quantum Era of HPC: Roadmaps, Challenges and Opportunities in Navigating the Integration Frontier
November 19th | 10:30 – 12:00pm CST
During this panel session, Kentaro Yamamoto from Quantinuum, will join experts from Lawrence Berkeley National Laboratory, IBM, QuEra, RIKEN, and Pawsey Supercomputing Research Centre to explore how quantum and classical systems are being brought together to accelerate scientific discovery and industrial innovation.
BoF Session: Bridging the Gap: Making Quantum-Classical Hybridization Work in HPC
November 19th | 5:15 – 6:45pm CST
Quantum-classical hybrid computing is moving from theory to reality, yet no clear roadmap exists for how best to integrate quantum processing units (QPUs) into established HPC environments. In this Birds of a Feather discussion, co-led by Quantinuum’s Grahame Vittorini and representatives from BCS, DOE, EPCC, Inria, ORNL NVIDIA, and RIKEN we hope to bring together a global community of HPC practitioners, system architects, quantum computing specialists and workflow researchers, including participants in the Workflow Community Initiative, to assess the state of hybrid integration and identify practical steps toward scalable, impactful deployment.