The QIS seminar is our regular event at QIS where we give talks for each other and anyone who is interested.
It can be about our own work, or presenting interesting literature.
In case of questions, please contact Dominique Unruh.
| Date / Time | Speaker | Title | Authors |
|---|
► Wed, Jun 10, 2026
10:30 |
Benjamin |
Automatic Quantum Uncomputation by Affine Types with Lifetime |
Kengo Hirata, Chris Heunen |
Abstract: In classical programming, temporary values can be ignored or discarded with a simple function call. In quantum computing, a programmer has to manually make sure that such values are explicitly and safely uncomputed, which is both error-prone and obscures an algorithm's core logic. The Qurts programming language proposes a system where temporary values are assigned "lifetimes" that track the scope in which they can be uncomputed. This allows a compiler to perform uncomputation automatically. I will present a simplified version of Qurts type system to showcase this approach. The concept of lifetimes and the overall design of Qurts is heavily inspired by Rust, but the talk assumes no prior knowledge on it.
URL: https://arxiv.org/abs/2411.10835 |
| ► Tue, Jun 3, 2025 |
Christina |
Bayesian Inference in Quantum Programs |
(own work) |
Abstract: Conditioning is a key feature in probabilistic programming to enable modeling the influence of data (also known as observations) to the probability distribution described by such programs. Determining the posterior distribution is also known as Bayesian inference. This paper equips a quantum while-language with conditioning, defines its denotational and operational semantics over infinite-dimensional Hilbert spaces, and shows their equivalence. We provide sufficient conditions forthe existence of weakest (liberal) precondition-transformers and derive inductive characterizations of these transformers. It is shown how w(l)p-transformers can be used to assess the effect of Bayesianinference on (possibly diverging) quantum programs. |
| ► Tue, May 20, 2025 |
Nikolaos |
Convergence criteria for Quantum Gibbs Samplers |
(own work) |
Abstract: In classical systems, convergence to equilibrium—such as in Gibbs sampling—is relatively straightforward to analyze and monitor, thanks to the ability to freely copy and measure system states. In the quantum world, that luxury evaporates: the no‑cloning theorem forbids perfect copying, and every measurement perturbs (or even destroys) the very state we need to inspect. This talk asks a practical question that arises in quantum simulation of open systems: How can we certify that a Lindbladian dynamics meant to prepare a thermal (Gibbs) state has run long enough? We will explore the intimate connection between Lindblad evolution and Markov Chain Monte Carlo and use physical intuition to prescribe a stopping rule for our algorithms |
| ► Tue, Jan 14, 2025 |
Dominique |
Quantum References |
(own work) |
Abstract: I will present the theory of "quantum references", similar to lenses in classical functional programming, that allow to point to a subsystem of a larger quantum system, and to mutate/measure that part. Mutable classical variables, quantum registers, and wires in quantum circuits are examples of this, but also references to parts of larger quantum datastructures. Quantum references in our setting can also refer to subparts of other references, or combinations of parts from different references, or quantum references seen in a different basis, etc. Our modeling is intended to be well suited for formalization in theorem provers and as a foundation for modeling variables in quantum programs.
URL: https://arxiv.org/abs/2105.10914 |