The current quantum software stack, while foundational, faces critical scaling challenges that threaten to bottleneck the future of quantum computing. Developed alongside the first generation of online quantum hardware platforms, these software stacks are defined by a common set of quantum software architectures and ideas: Python-based libraries, small loosely structured programs, shared but restrictive program representations (OpenQASM), online queues, wasteful execution models (e.g., unnecessary repetition, client-server latency), and a computational separation between classical and quantum instructions. A number of these components will not scale, bottlenecking the performance of quantum computing overall. To overcome these limitations and unlock the potential of large-scale quantum computing, a paradigm shift is needed: the development of Quantum Software 2.6.
Anticipating such limitations, a number of organizations have already been looking towards the next generation of ideas. We can expect a more complex and multi-faceted tech stack: deeper, wider, and more complex circuits, first versions of quantum error correction, just-in-time compilation, multi-level IRs, heterogeneous execution models including quantum-centric supercomputing, co-location, and the improved utilization of existing classical software tools.
In this workshop, we highlight a number of software barriers that will have to be overcome to unlock this next stage of development. We will hear from guest speakers, panelists, and attendees who have begun experimenting, prototyping, and releasing early versions of next-generation quantum software technologies. We hope to identify and form consensus about the most promising approaches to pursue in the future that could enable scaling for effective and robust heterogeneous infrastructure development, as well as foster interest in developing these technologies collectively under open models for the benefit of the quantum industry as a whole.
10:00 - 10:05: Introduction
Josh Izaac, Xanadu
10:05 - 10:25: Opening talk
Lee J. O'Riordan, Xanadu
10:25 - 11:10: Lightning talks
Olivia Di Matteo, The University of British Columbia
Yuan Liu, North Carolina State University
Nils Quetschlich, Amazon Braket
Jakob S. Kottmann, University of Augsburg
11:10 - 11:30: Panel discussion
Lee J. O'Riordan, Olivia Di Matteo, Yuan Liu, Ryan Shaffer, Jakob S. Kottman
13:00 - 13:20: Opening talk
Ross Duncan, Quantinuum
13:20 - 14:10: Lightning talks
Rafael Haenel, QuEra Computing Inc
Brad Chase, Unitary Foundation
Sebastian Feld, Delft University of Technology
Mathys Rennela, Unitary Foundation / Mozilla
14:10 - 14:30: Panel discussion
Ross Duncan, Xiuzhe (Roger) Luo, Brad Chase, Sebastian Feld, Mathys Rennela
15:00 - 15:20: Opening talk
Fred Chong, University of Chicago / Infleqtion
15:20-15:45: Lightning talks
Peter Groszkowski, Oak Ridge National Laboratory
Mateo Uldemolins, INRIA
15:45 - 16:05: Panel discussion
Fred Chong, Mateo Uldemolins, Edwin Tham, Priya J Nadkarni
16:05 - 16:30: General panel discussion and structured brainstorming
Robert Wille, Blake Johnson, Justin Gage Lietz, Laura Schulz
Talk: Programming of heterogeneous quantum workloads for low-latency FTQC R&D
Abstract
Moving to fault-tolerant quantum computing requires ultra-low latency without sacrificing developer experience. In PennyLane we have built Backline, a compiler and runtime framework that lowers Python directly to distributed FPGAs, CPUs, and GPUs with microsecond-scale data transfer.
Bio
Physicist, purveyor of angular momentum, GPUs, pointy guitars, and computational things. Working on building out the software stack for quantum stuff.
Projects: jeff and CircInspect
Talk: The Importance of Structured Quantum Programs for Compilation
Abstract
Today’s quantum software enables users to implement quantum algorithms with a combination of classical logic and quantum operations. This makes quantum programs easier to write and interpret, but adds structural elements such as loops and control flow that go beyond the quantum circuit model. This presents a challenge to quantum compilers that work by mapping circuits to other circuits: programs with structure must first be flattened into circuits, and that structure is lost. In this talk I will argue that the next generation of quantum compilers must be able to represent, preserve, and leverage this structure for scalable compilation. I will highlight advantages of frameworks where this is already possible, share ongoing collaborative efforts to define a set of structured quantum benchmark programs, and showcase CircInspect, our interactive visualizer and debugger for structured programs.
Bio
Olivia Di Matteo is an Assistant Professor in the Electrical and Computer Engineering department at UBC and the Tier 2 Canada Research Chair in Quantum Software and Algorithms. She obtained her PhD at the University of Waterloo and Institute for Quantum Computing in 2019 in Physics (Quantum Information). Following her PhD she worked as a Quantum Information ScienceAssociate at TRIUMF, and as a Quantum Computing Educator and Researcher at the Toronto-based quantum startup Xanadu. At UBC she leads the Quantum Software and Algorithms Research Lab, whose work focuses on designing and implementing open-source software for quantum compiler tools and physics applications.
Projects: hybridlane and Genesis CV-DV Compiler
Talk: Quantum softwares for hybrid continuous-discrete-variable quantum computing
Abstract
Emerging quantum hardware hybridizing continuous-variable (CV) and discrete-variable (DV) quantum systems offers a powerful computational paradigm that inherits the strengths of both DV and CV processors. However, quantum software ecosystems tailored for hybrid CV-DV quantum computing are much under developed. This talk will highlight and showcase a collection of recent progress on software tools for programming, compilation, and benchmarking hybrid CV-DV quantum algorithms and circuits.
Bio
Yuan Liu is an Assistant Professor of Electrical and Computer Engineering and Computer Science at North Carolina State University. He is also an affiliated faculty in Physics. He received his B.S. in physics (with honors) from Tsinghua University in Beijing. He received his M.S. in electrical engineering and a Ph.D. in chemical physics with the William R. Potter Prize from Brown University in Providence, Rhode Island. Prior to joining NC State faculty, he was a postdoctoral researcher in the Research Laboratory of Electronics and Department of Physics at the Massachusetts Institute of Technology in Boston.
Project: qiskit-braket-provider
Talk: Recent advances toward dynamic circuit support on Amazon Braket
Abstract
Dynamic circuits are essential to conduct (early) quantum error correction (QEC) experiments. This presentation will highlight our recent features and developments to make it easier for researchers to run these circuits on Amazon Braket. We will cover the qiskit-braket-provider as a client-side solution for control flow compilation and the updated mid-circuit measurement simulator for local prototyping. Additionally, we present program sets as a structured execution model for error mitigation workloads, which are expected to coexist with QEC at least in the early fault-tolerant regime. Beyond feature updates, we discuss the challenges of transitioning into the QEC era, including what changes, what breaks, and where uncertainty remains.
Bio
Nils Quetschlich is an applied scientist at Amazon Web Services working on Amazon Braket. There, he contributes to the software stack that validates and compiles quantum programs for Braket's supported hardware providers. He completed his PhD at the Technical University of Munich in 2025, where he focused on quantum computing software.
Project: Unitaria
Talk: Unitaria: Quantum Linear Algebra via Block Encodings
Abstract
Unitaria is a Python library that brings NumPy-like simplicity to quantum algorithms based on block encodings, the abstraction in which a matrix is embedded as a sub-block of a larger unitary. Its key feature is a matrix-arithmetic evaluation path that computes every operation directly on encoded objects.
Bio
Jakob S. Kottmann is Professor of Quantum Algorithmics in the Institute of Computer Science at the University of Augsburg, where he was appointed as part of the Bavarian High-Tech Agenda and is a member of the Centre for Advanced Analytics and Predictive Sciences (CAAPS).
Additional bios:
Ryan Shaffer (He/Him/His), Applied Science Manager, Amazon Braket
Ryan Shaffer is an Applied Science Manager at Amazon Braket, where he leads a team of scientists and engineers building tools for quantum programming and execution. He holds a PhD in Physics from UC Berkeley, where his work focused on efficient operation and verification of quantum computers. He has previously worked for Microsoft, Meta, and Sandia National Labs.
Speaker: Ross Duncan (He/Him/His), Senior Fellow, Quantinuum
Talk: Software for Leaving NISQ Behind
Abstract
The NISQ era was fun, but it is time to leave childish things behind. Two key problems future quantum software must address are programming in the large, and fault-tolerance. I will discuss some recent efforts at Quantinuum to fill these gaps.
Bio
Ross Duncan is a Senior Fellow at Quantinuum. He obtained his Doctorate from Oxford University in 2006 for his thesis “Types for Quantum Computation”. Since then he has held positions as an EPSRC Postdoctoral Research Fellow at the University of Oxford, Chargé de Recherche at the Université Libre de Bruxelles, and Lecturer of Computer Science at the University of Strathclyde. His academic work focussed on the foundations of quantum computing and in particular on the use of category theory and diagrammatic calculi to better understand the structure of quantum states and programs; he is the co-inventor (with Bob Coecke) of the ZX-calculus and has applied this to reason about quantum circuits, measurement-based quantum computation, and quantum error correcting codes. Since joining CQC (later Quantinuum) in 2018, he has worked on compilers, programming languages, and HPC integrations for quantum computers.
Project: Tsim
Talk: Tsim: Fast Universal Simulator for Quantum Error Correction
Abstract
We present Tsim, an open-source high-throughput simulator for universal noisy quantum circuits targeting quantum error correction. Tsim represents quantum circuits as ZX diagrams, where Pauli channels are modeled as parameterized vertices. Diagrams are simplified via parameterized ZX rules, and then compiled for vectorized sampling with GPU acceleration. After the one-time compilation, one can sample detector or measurement shots in linear time in the number of Clifford gates and exponentially only in the number of non-Clifford gates. Tsim implements the Stim API and fully supports the Stim circuit format, extending it with T and arbitrary single-qubit rotation instructions. For low-magic circuits, Tsim throughput can match the sampling performance of Stim.
Bio
Rafael Haenel is a Senior Scientific Software Developer at QuEra Computing, where he works at the intersection of quantum error correction, compiler infrastructure, and neutral-atom quantum computing architectures. His work focuses on scalable software systems for fault-tolerant quantum computing on neutral-atom hardware. Prior to joining QuEra, he worked at Photonic Inc. and completed his PhD at the University of British Columbia in condensed matter theory.
Project: Clifft
Talk: Compiling Quantum Circuits for Classical Simulation
Abstract
Quantum compilers are usually framed as tools for producing better quantum circuits. In QEC-era workloads, however, much of the scaling pressure appears on the classical side: simulation, sampling, decoding, postselection, control flow, and repeated execution. This talk uses Clifft, an exact near-Clifford simulator, as a case study in treating those classical costs as compiler targets.
Clifft compiles a circuit into a hybrid execution plan: deterministic Clifford structure is kept symbolic and moved out of the shot loop, while only the active non-Clifford subspace is materialized as dense classical memory. The resulting cost model is not just qubit count or gate count, but the peak number of active virtual qubits the runtime must remember. This provides a concrete example of a broader thesis: QEC-era quantum software workloads will benefit from applying compiler thinking beyond circuit optimization.
Bio
Brad joined the Unitary Foundation in 2025 as a Member of Technical Staff, where he researches and develops open-source quantum compilation and simulation software. He earned his Ph.D. from the University of New Mexico in 2009 with a focus on parameter estimation and model reduction in the context of continuous quantum measurement. In the intervening years, Brad served as an engineering leader within the blockchain and high-frequency trading industries.
Project: QGYM
Talk: Designing the Learning Problem: Lessons from Reinforcement-Learning Quantum Compilers
Abstract
Quantum compilation is increasingly being approached as a reinforcement-learning problem, but the success of these methods depends critically on how the problem is formulated. Using QGYM, an extensible framework for reinforcement-learning-based initial mapping, routing, and scheduling, we studied the effects of reward functions, action spaces, compiler-aware representations, and hardware information. The results show that minimizing conventional proxies such as SWAP count does not necessarily minimize execution time or maximize hardware fidelity; that action-space design and heuristic guidance can be more influential than richer observations; and that compiler semantics such as gate commutation provide valuable inductive bias. This talk argues that reinforcement learning is most useful not as a drop-in replacement for compiler heuristics, but as a systematic framework for designing and evaluating multi-objective, hardware-aware compilation strategies.
Bio
Sebastian Feld is an associate professor at Delft University of Technology, The Netherlands, where his research focuses on quantum computing architecture and applications. His group develops scalable quantum computing architectures while exploring ways to leverage these systems for real-world challenges. On the architecture side, he works to optimize quantum circuit design and multi-core systems for more efficient computation. On the application side, he investigates quantum algorithms to address complex problems like optimization and planning, effectively bridging the gap between advanced hardware development and practical quantum applications. Previously, he led the Quantum Applications and Research Laboratory (QAR-Lab) at LMU Munich, concentrating on quantum-assisted artificial intelligence and optimization problems. He earned his doctorate from LMU Munich with research in time series analysis.
Project: emlint
Talk: Catching Bugs in Detector Error Models (Before Your Decoder Fails)
Abstract
Fault-tolerant compilation pipelines produce Detector Error Models (DEMs) at every stage: after syndrome extraction, after temporal composition, after lattice-surgery gluing. These DEMs feed directly into decoders. DEM-level bugs (e.g. incorrect probability, index or target) silently inflate the logical error rate and may not surface until 10⁶ simulation shots, or at all.
We present emlint, a static analyzer for DEMs that catches structural bugs before they reach the decoder. emlint checks probability bounds, detector reachability, observable coverage, sensitivity, and performs qualitative assessments (like bounding distance).
The talk will demonstrate three scenarios: (1) a single-mechanism bug that a human reviewer missed, caught in 2ms; (2) a property violation (distance) across a composite DEM that silently degrades decoder performance; and (3) the exit-code contract driving a CI gate. We argue that static analysis for DEMs fills a QA gap in quantum compilation pipelines that no existing tool addresses.
Bio
Mathys Rennela is a quantum software researcher based in Paris, currently developing a static linter for quantum error correction.
Abstract
Fault-tolerant compilation pipelines produce Detector Error Models (DEMs) at every stage: after syndrome extraction, after temporal composition, after lattice-surgery gluing. These DEMs feed directly into decoders. DEM-level bugs (e.g. incorrect probability, index or target) silently inflate the logical error rate and may not surface until 10⁶ simulation shots, or at all.
We present emlint, a static analyzer for DEMs that catches structural bugs before they reach the decoder. emlint checks probability bounds, detector reachability, observable coverage, sensitivity, and performs qualitative assessments (like bounding distance).
The talk will demonstrate three scenarios: (1) a single-mechanism bug that a human reviewer missed, caught in 2ms; (2) a property violation (distance) across a composite DEM that silently degrades decoder performance; and (3) the exit-code contract driving a CI gate. We argue that static analysis for DEMs fills a QA gap in quantum compilation pipelines that no existing tool addresses.
Bio
Mathys Rennela is a quantum software researcher based in Paris, currently developing a static linter for quantum error correction.
Additional bios:
Xiuzhe (Roger) Luo (He/Him/His), Director of Scientific Software, QuEra Computing Inc.
Xiu-Zhe (Roger) Luo is the Director of Scientific Software at QuEra Computing, where he leads the development of quantum compiler infrastructure, numerical tools, and algorithms for neutral atom platforms. Roger did his PhD work at the University of Waterloo and the Perimeter Institute studying computational quantum many-body physics and machine learning methods. He is the recipient of the 2020 Wittek Quantum Prize for his outstanding contributions to open-source quantum software. He is the lead developer of Yao.jl, a high-performance and differentiable quantum circuit simulation framework, and the primary architect of QuEra's compiler pipeline for neutral atom systems. He has also contributed to a number of widely used open-source projects in the scientific computing ecosystem, including the Julia compiler and PyTorch.
Talk: Tailoring QEC Protocols to Algorithms and Hardware
Abstract
Recent progress in high-rate QEC codes have opened up a wide range of options when designing protocols for a machine. At the same time, a number of promising machine platforms offer differing models for computation and communication. I will discuss a few examples of tailoring codes to QEC protocols to specific machines. I will also discuss tailoring logical gatesets to applications.
Bio
Fred Chong is the Seymour Goodman Distinguished Service Professor in the Department of Computer Science at the University of Chicago and the Chief Scientist for Quantum Software at Infleqtion. He was the Lead Principal Investigator for the EPiQC Project (Enabling Practical-scale Quantum Computing), an NSF Expedition in Computing from 2018-2024. Chong was a member of the National Quantum Advisory Committee (NQIAC) from 2020-2025, which provided advice to the President on the National Quantum Initiative Program. In 2020, he co-founded Super.tech, a quantum software company, which was acquired by Infleqtion (formerly ColdQuanta) in 2022. Chong received his Ph.D. from MIT in 1996 and was a faculty member and Chancellor's fellow at UC Davis from 1997-2005. He was also a Professor of Computer Science, Director of Computer Engineering, and Director of the Greenscale Center for Energy-Efficient Computing at UCSB from 2005-2015. He is a fellow of the ACM and the IEEE, a recipient of the NSF CAREER award, the Intel Outstanding Researcher Award, and 17 best paper awards. He is also a recipient of the Quantrell Award, the oldest undergraduate teaching award in the United States, as well as the University of Chicago's Graduate Teaching and Mentoring Award.
Project: scqubits
Talk: Simulating superconducting circuits with scqubits
Abstract
In recent years, open source software development has played a crucial role in fueling technological advances across a broad range of disciplines, including ones related to quantum information science (QIS). One important area of QIS research involves building software tools that allow for accurate modeling and simulations of early quantum computing devices. In this talk I will discuss scqubits[1]: an open-source Python package for simulating and analyzing superconducting circuits - arguably one of the leading approaches to building early quantum computers. I will outline its core functionality, features, as well as limitations. I will also briefly present more recently added facilities for arbitrary circuits analysis (along with coherence time estimates), and talk about our ongoing efforts related to performance enhancements as well as building tooling required to take advantage of GPU-based computing.
[1] https://github.com/scqubits/scqubits
Bio
Peter Groszkowski is a Scientist at the National Center for Computational Sciences (NCCS). He is interested in various areas of physics, mainly related to quantum computing and information.
Project: Graphix
Talk: Graphix: A software framework for Measurement-Based Quantum Computation
Abstract
Measurement-Based Quantum Computing (MBQC) is an alternative model of quantum computation in which algorithms are executed through adaptive single-qubit measurements on a highly entangled resource state. Although MBQC is computationally universal and offers a powerful framework beyond the circuit model, its software ecosystem remains comparatively underdeveloped.
To address this gap, we develop Graphix, an open-source Python library for MBQC research. Graphix provides native abstractions for core MBQC concepts, including measurement patterns and open graphs, together with implementations of established algorithms for transpilation, optimisation, simulation, flow finding, and circuit extraction. The library is designed to be modular, extensible, and easy to use, providing a solid foundation for developing MBQC applications and compilation techniques.
In this lightning talk, we present the Graphix architecture, highlight its latest features, and demonstrate how to implement and execute a basic MBQC computation using the library.
Bio
Mateo Uldemolins is a research software engineer at the Quantum computing Architectures, Algorithms, Applications and their Theory research group at INRIA (France) where he works to support the group’s quantum software needs. For the past year, he’s been a maintainer of Graphix, an open-source project for measurement-based quantum computation. Previously, he did research on superconductivity and holds a Ph.D. in theoretical condensed matter physics.
Panelists: Fred Chong, Mateo Uldemolins, Edwin Tham, Priya J Nadkarni
Bios:
Edwin Tham (He/Him/His), IonQ Canada
Edwin is a physicist by training. He completed a PhD in Quantum Optics, Atomic and Molecular (QOAMO) Physics, at the University of Toronto. After graduate school, he co-founded Agnostiq, a Toronto-based startup focused on privacy protocols for delegated quantum computing. That startup was recently acquired by DataRobot Inc. He was also an early employee at a different Toronto-based startup — Entangled Networks Inc. — where he was responsible for research in circuit synthesis for distributed quantum circuits. After its acquisition by IonQ, he now works as a quantum error-correction (QEC) researcher, focused on fault-tolerant architectures.
Priya J Nadkarni (She/Her/Hers), Xanadu Quantum Technologies
Priya J. Nadkarni is a Lead Quantum Architecture Scientist at Xanadu, leading the design efforts for logical magic state factories in fault-tolerant, bosonic-based photonic quantum computers. She earned her Ph.D. and M.Sc. in Engineering from IISc Bengaluru, and a B.E. from BMS College of Engineering. Prior to her doctorate, she worked in RF R&D at National Instruments. Dr. Nadkarni’s research spans quantum error correction, fault-tolerant quantum computation, and quantum communication. Her work is widely published and presented at premier events, including various IEEE conferences, the 2024 QuIK Workshop, the QEC Conference, etc. She is an IEEE HKN member and has served as Chair of the IEEE-IISc ComSoc Student Chapter, Secretary of IEEE-IISc WISE, and Corresponding Secretary of the IEEE-IISc HKN Chapter. Her contributions have been recognized with the IEEE Bangalore Section's "Best Researcher Award – IISc" and the IEEE-IISc Outstanding Officer Award.
Panelists: Robert Wille, Blake Johnson, Justin Gage Lietz, Laura Schulz
Bios:
Robert Wille (He/Him/His), CEO & Professor, MQSC & Technical University of Munich
Robert Wille is a Full and Distinguished Professor at the Technical University of Munich, Co‑Founder and CEO of the Munich Quantum Software Company (MQSC), and Scientific Director at the Software Competence Center Hagenberg (a technology‑transfer organization with 100 employees). His passion for Computer Science took him into the lecture halls of various universities. In the research lab, he explores how future computers — particularly quantum technologies — can be designed and programmed. For more than 15 years, he has been advancing the field of quantum computing, developing foundational software and design‑automation concepts that help make this emerging technology practical and scalable.
Blake Johnson, Distinguished Engineer, QEC Infrastructure, IBM
Blake Johnson is a Distinguished Engineer at IBM. He is responsible for R&D teams delivering compilation, control, and decoding infrastructure for fault-tolerant quantum computers. Blake has previously worked across many elements of the quantum computing stack, including characterization protocols, quantum programming languages, device design, control systems, and system architecture. Prior to IBM, Blake was Chief Quantum Engineer at Rigetti and Senior Scientist at Raytheon BBN. He earned his PhD in physics from Yale.
Justin Gage Lietz (He/Him/His), Research Scientist, NVIDIA
Justin Gage Lietz is a research scientist and quantum computing architect at NVIDIA, focused on quantum error correction and integrating quantum computers with classical HPC systems. Prior to NVIDIA, Justin was on the research staff at the National Center for Computational Sciences at Oak Ridge National Laboratory, where he developed scientific applications for leadership-class supercomputers. Justin received his Ph.D. in computational nuclear physics in 2019 from Michigan State University, where his research applied high-performance computing to quantum many-body systems.
Laura Schulz (She/Her/Hers), Lead for Quantum Innovation, Argonne National Laboratory
Laura Schulz is Quantum Innovation Lead at the Argonne Leadership Computing Facility, where she leads the integration of quantum computing into HPC and AI infrastructure for scientific computing. Her work focuses on the systems, software, and operational foundations required to make quantum processors practical components of advanced computing environments, including heterogeneous system architecture, workflow orchestration, portable interfaces, and end-to-end HPC–AI–quantum workflows.
Before joining Argonne, she served as Head of the Quantum Computing and Technologies Department at the Leibniz Supercomputing Centre within the Munich Quantum Valley and as Principal Investigator for EuroHPC’s Euro-Q-Exa project. In these roles, she helped shape quantum–HPC integration across European research infrastructure, system procurement, software initiatives, and user programs.
Xanadu
Entropica Labs
IonQ
Oak Ridge National Lab
Xanadu
Quantinuum