Aleksander Wennersteen

Aleksander Wennersteen

Quantum, ML, HPC, Software

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A list of all the posts and pages found on the site. For you robots out there is an XML version available for digesting as well.

Pages

Posts

Recreating Gandalf by Lakera

6 minute read

Published:

I discovered Lakera’s Gandalf game, an educational AI challenge on prompt injections and hallucinations, and tried to recreate its levels using GPT-4o to understand how defenses work and where vulnerabilities appear.
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Generative AI security

11 minute read

Published:

This post explores generative AI, how large language models process prompts, and the threat of prompt injection attacks. Illustrating vulnerabilities and defensive considerations.
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Power of abstraction

4 minute read

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This essay discusses the role of abstraction in programming and mathematics, showing how focusing on high-level structures can manage complexity, enhance readability, and inform performance-oriented design.
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Architecting new projects

4 minute read

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This post shares insights on initiating new software projects, emphasizing the iterative nature of requirements gathering, stakeholder alignment, and balancing technical ambition with maintainable progress.
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IEEE QCE impression

3 minute read

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Some thoughts I was left with after this years IEEE quantum week, with extra focus on the numerical simulation and software architecture workshops. Conferences like these are truly important to the community. What I particularly liked about the IEEE Quantum Week talks where how they for the most part were truly responsible and providing a nuanced view without the overhyping that one often sees for example at the more business oriented conferences. The program catered to many different interests and this resulted in some very interesting lunch-time conversations. Among attendees there were those who work in quantum software and hardware, but also the rest of the software stack, algorithms, applications and so on. There were plenty of attendees both from industry and academia and it’s always interesting to discuss and see how views differ.
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ISC-HPC impression

3 minute read

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ISC-HPC, “The Event for High Performance Computing, Machine Learning, Data Analytics & Quantum Computing” is a yearly conference focused on HPC but also more and more on the adjacent topics above. The amount of quantum focus in this years ISC was astonishing. A non-exhaustive list of events were the full-day QML tutorial on Sunday, full day workshop on Thursday, several posters, sessions on the EuroHPC efforts, the HPCQS and similar projects, the ETP4HPC quantum project, and a session on industry usecases. The level was all-throughout very high.
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publications

Qadence a differentiable interface for digital and analog programs

Published in IEEE Software, 2025. Paper available.

In this work we present Qadence, a high-level programming interface for building complex digital and analog quantum programs. Digital-analog quantum computing (DAQC) is an alternative paradigm for universal quantum computation combining digital gates with global analog operations acting on a register of interacting qubits. Currently, no available open-source software is tailored to express, differentiate, and execute programs within the DAQC paradigm. Qadence addresses this shortfall by seamlessly allowing the user to combine digital and analog primitives. With a flexible interface and focus on native differentiability, Qadence aims to support research in variational algorithms in these hybrid computational models.
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Towards a user-centric HPC-QC environment

Published in SC'25 workshops proceedings, 2025. Paper available.

Robust execution environments are important for addressing key challenges in quantum computing, such as application development, portability, and reproducibility, and help unlock the development of modular quantum programs, driving forward hybrid quantum workflows. In this work, we show progress towards a basic, but portable, runtime environment for developing and executing hybrid quantum-classical programs running in High Performance Computing (HPC) environments enhanced with Quantum Processing Units (QPUs). The middleware includes a second layer of scheduling after the main HPC resource manager in order to improve the utilization of the QPU, and extra functionality for observability, monitoring, and admin access. This approach enables managing multiple programming Software Development Kits (SDKs) as first-class citizens in the environment by building on a recently proposed vendor-neutral Quantum Resource Management Interface (QRMI). Lastly, we discuss and show a solution for the monitoring and observability stack, completing our description of the hybrid system architecture.
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talks

Pulse level simulation of neutral atom QPUs

Published:

I presented on behalf of Pasqals emulation team our work on tensor network simulations of pulse level programming of neutral atom QPUs as well as our work on differentiable simulators for digital-analog algorithms. The work presented centred around our whitepaper for the cloud-based tensor network emulator (EMU-TN)[https://arxiv.org/abs/2302.05253] and the emulators built for the then not yet released (Qadence)[https://github.com/pasqal-io/qadence] digital-analog quantum programming interface.
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Qadence @ POPL24

Published:

I gave a talk about our digital-analog programming language Qadence at the Fourth International Workshop on Programming Languages for Quantum Computing (PLanQC 2024) at the 51st ACM SIGPLAN Symposium on Principles of Programming Languages (POPL 2024).
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European Quantum Software and Systems Summit (EQS3)

Published:

European Quantum Software and Systems Summit (EQS3)’s third edition took place the 17th - 19th of April 2024 at DTU in Denmark. Some interesting days of discussions between the quantum and HPC world with particular focus on abstractions, handoff points and to what extent the different qubit modalities have different so requirements we need separate stacks. I presented Pasqal’s current architecture and some of our viewpoints for the future.
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Supercomputing SC24

Published:

Supercomputing 2024 took place 17th - 22nd of November 2024 in Atlanta.. With a record of over 18 000 attendees and almost 500 exhibitors it’s the highlight of the HPC calendar. It was great to catch up with friends, partners, and new connections and to discuss with all the other attendees. I gave talks at Pasqal’s booth and at partner booths.
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FOSDEM Quantum Computing Devroom

Published:

I gave a talk at the Quantum Computing devroom @ FOSDEM 2025 organised by the Unitary Fund. FOSDEM is a free event for the free and open source software community. The turnup for the quantum devroom was amazing, hopefully to be repeated in the future. The talk was titled “No-one used my software: a tale of quantum software engineering”, and was about the practical experience of writing quantum software for a living over the years. We touched on issues ranging from quantum physics and hardware to user interaction, requirements gathering and community building. It was great to share experiences with the community!
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Software at the intersection of Quantum and HPC & heterogeneous quantum computing

Published:

At this years ISC I gave two talks, and also a “meet the experts” session at the booth of the Julich Supercomputing Center. IBM Quantum had a workshop where themselves and partners gave updates on the the state of quantum-centric supercomputing (QCSC). I gave a talk on “Software for heterogeneous quantum computing”, presenting our joint work on creating a joint software-stack for QCSC. Primarily the work on resource management, the associated code for spank plugins for quantum resources and jobs, and our Qiskit integration.
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Towards quantum-classical supercomputing with neutral atoms

Published:

I had the pleasure of attending the 32nd edition of the invite-only “International Advanced Research Workshop on High Performance Computing” held, as always, in Cetraro (Italy), June 23 – 27, 2025 to present our strategy towards quantum supercomputing at Pasqal.
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Material Science Working Group Meeting

Published:

Attended the yearly all-hands of the “Quantum-centric Supercomputing for Materials Science” working group organized by IBM and held at the R-CCS in Kobe. We had 2 days of talks and discussions focused on quantum-HPC integration and applications in materials science, chemistry and condensed matter.
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Supercomputing SC25

Published:

This year at Supercomputing I will have two main talks. I gave a talk at the 1st Annual Workshop on Large Scale Quantum-Classical Computing, titled “QC-HPC Systems for the Quantum Advantage Era​” giving an overview of Pasqal’s QPU, applications in material science and our HPC-QC work. And another talk on “Towards a user-centric HPC-QC environment” at the 1st International Workshop on Software Frameworks and Workload Management for Quantum and HPC Ecosystems. The accompanying paper is available in the workshop proceedings.
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EQS3 VI QRMI Overview

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European Quantum Software and Systems Summit (EQS3)’s 6th edition took place the 9th-11th of December 2025 at the LINKS Foundation in Torino, Italy. This session was focused on the software connecting QCs to the HPC infrastructure, particularly centered around the QDMI (Quantum Device Management Interface) From the MQSS. I was invited to give an overview to our similar QRMI (Quantum Resource Management Interface) and discuss how they compare and might co-exists and co-evolve in the future.
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Open Compute Project: QPU Integration

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I was invited to give a talk titled “Making QPUs First-Class HPC Resources” at the Open Compute Project’s Future Technology Initiative (OCP FTI) Data Center Integration of Quantum Information Infrastructure working group. The talk focused on the software side of HPC integration, and how this may generalise to general data center integration of QPUs. A LinkedIn event was made, and I will add the recording once available.
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OpenQSE

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I gave a talk at the OpenQSE (Open QHPC Software Ecosystem) initiative’s architecture seminar series focused on the Q-HPC middleware we are developing at Pasqal such as a 2nd level scheduler that will take care of scheduling the quantum tasks from within the HPC allocation. You can find the meeting notes and transcript here. The slides will appear on the GitHub repo. And you can even watch the recording.
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