Institut for Matematik og Datalogi

FNUG og NAFA inviterer til NiSE-webinar

De nye læreplaner i matematik er trådt i kraft - men hvad betyder de egentlig for undervisningen og elevernes læring?

Speaker: Thomas Klein Kvorning (​KTH Royal Institute of Technology). Abstract: Simulating quantum many-body systems is fundamentally challenging because quantum states encode correlations that cannot be decomposed into local parts, leading to an exponential growth of required resources with system size. Yet physical observables are typically local: they are fully determined by density matrices of small subsystems. This raises a central question: can local density matrices be time-evolved without explicitly tracking long-range correlations? In this talk, I address this question using the framework of the information lattice, a scale-resolved decomposition of the information content of a quantum state. This construction provides a precise notion of where information resides in a quantum system, both in space and across length scales, and thereby offers a diagnostic of how correlations build up dynamically. I will show how this perspective reveals regimes in which local degrees of freedom are exactly decoupled from long-range entanglement, as well as how it can guide the development of approximate numerical methods for ab initio simulation of condensed matter systems.

Speaker: Julio C. Magdalena de la Fuente (Freie Universität Berlin).Abstract: Topological quantum error correction encodes quantum information in the ground space of a topologically ordered lattice system or in the fusion space of topological defects. In this talk I will focus on the former. To use such codes for reliable quantum computation, one must design low-overhead circuits that protect and manipulate the encoded information in a fault-tolerant way.I will start with presenting simple protocols based on two-dimensional topological codes that are composed of 2D local gates. Representing these protocols as tensor networks local in a 3D spacetime lattice leads to a useful viewpoint. We identify a topological QEC circuit with an imaginary-time topological path integral of a topological gauge theory. Within this picture, both physical errors and non-trivial measurement outcomes appear as certain defects in the path integral and their combinatorial structure defines the associated classical decoding problem.I will go through the construction of logically non-trivial fault-tolerant gates using topological boundaries and domain walls between topological phases. In order to perform universal computation a non-Abelian state must be stabilized during the computation. The path-integral perspective allows to calculate the logical action and extract the resulting causality constraints on the classical decoder that is needed to make the protocols resilient to arbitrary errors. It also provides an efficient way to simulate the success of a given decoding strategy using Monte-Carlo sampling based on third-order cohomology invariants of the underlying spacetime complex. I want to introduce the necessary ingredients to construct and analyze such QEC protocols for their performance and argue about their reliable implementation in the presence of errors.

Speaker: Olga Solodovnikova (University of Southern Denmark).Abstract: In this seminar, I will introduce continuous quantum variables [1], which are used to describe systems of oscillators, that is, systems with infinite Hilbert spaces such as photonic systems or the vibrational motion of trapped ions. To build a universal and fault-tolerant quantum computer with a continuous-variable system, it is necessary to encode a qubit in an oscillator, perform gates from the universal gate set, and measure stabilisers to implement error correction.  In the second part of the introductory seminar, I will introduce the measurement-based quantum computing framework for optical systems, in which Gottesman-Kitaev-Preskill (GKP) states are injected into a cluster state, and homodyne/heterodyne detectors are used to i) apply gates via teleportation and ii) measure stabilisers [2]. Lastly, I will discuss the experimental progress on building a measurement-based quantum computer [3], where, in particular, the generation of GKP states [4] is a major bottleneck due to photon loss. [1] Braunstein and van Loock. “Quantum Information with Continuous Variables.” Rev. Mod. Phys. 77, no. 2 (2005).[2] Gottesman, et al. “Encoding a Qubit in an Oscillator.” Physical Review A 64, no. 1 (2001): 012310. [3] Aghaee Rad, H., T. Ainsworth, R. N. Alexander, et al. “Scaling and Networking a Modular Photonic Quantum Computer.” Nature 638, no. 8052 (2025): 912–19. [4] Larsen, M. V., J. E. Bourassa, S. Kocsis, et al. “Integrated Photonic Source of Gottesman–Kitaev–Preskill Qubits.” Nature 642, no. 8068 (2025): 587–91.

Speaker: Olga Solodovnikova (University of Southern Denmark).Abstract: In this research seminar, I will discuss techniques for simulating continuous-variable circuits, which typically fall into two categories: phase-space simulation (Gaussian), and Fock-space simulation. I will present the methodology behind a CV circuit simulation library, which I developed during my PhD, which extends the Gaussian representation to systems that can be written as linear combinations of Gaussians. By approximating Fock states as superpositions of coherent states, any finite-energy CV state can be represented in this formalism. Furthermore, the complexity of this algorithm scales with the stellar rank of the non-Gaussian circuit elements. In the two manuscripts, I showcase the library by simulating and optimising GKP state preparation circuits in the presence of loss. Having said that, the formalism is applicable to any continuous-variable system. [1] Solodovnikova et al. “Fast Simulations of Continuous-Variable Circuits Using the Coherent State Decomposition.” arXiv:2508.06175 [quant-ph][2] Solodovnikova et al. “The Loss Tolerance of Cat Breeding for Fault-Tolerant Grid State Generation.” arXiv:2508.06193 [quant-ph]

Kom og vær med til 2 x 20 min. inspirerende foredrag, mens du nyder en gratis "afslappet after-work" øl med dine medstuderende, kollega eller lærer.Til denne IMADA Talk kan du møde postdoc Serhii Petrovych (emne: From Classroom to Living Lab: Rethinking STEM Learning through Sustainability Projects) og lektor Fabian Haiden (emne: Counting Problems: from Billiards to Quantum States).

Kageklubben er et nyt og hyggeligt initiativ, der samles fire gange hvert semester med gratis kaffe, kage og godt fællesskab.Så uanset om du studerer AI, Anvendt Matematik, Datalogi, Matematik eller Matematik-Økonomi, er du inviteret.Huske at tage dine studiekammerater med (undervisere er også velkomne).Klubmøderne holdes på IMADA Forskertorv.Læs evt. mere på Facebook-gruppen IMADA-students.

Speaker: Ben Brown (IBM).Abstract: TBA

Poster Session og oplæg ved Prajakt Pande, Lektor, Aarhus Universitet

Kageklubben er et nyt og hyggeligt initiativ, der samles fire gange hvert semester med gratis kaffe, kage og godt fællesskab.Så uanset om du studerer AI, Anvendt Matematik, Datalogi, Matematik eller Matematik-Økonomi, er du inviteret.Huske at tage dine studiekammerater med (undervisere er også velkomne).Klubmøderne holdes på IMADA Forskertorv.Læs evt. mere på Facebook-gruppen IMADA-students.

Abdullah Akgül forsvarer sin ph.d.-afhandling ved et offentligt foredrag: “Probabilistic Reinforcement Learning for Sample-Efficient Control”.Professor Arthur Zimek vil være ordstyrer ved arrangementet. Ph.d.-forsvaret finder sted i U181 (Ø22-601b-2).Alle er velkomne.

Hvordan bruger SDU-studerende AI-chatbots som personlige læringsværktøjer – og hvordan kan undervisere i naturfag guide studerende til en meningsfuld og fagligt relevant anvendelse?

Årets tema er FROM COGNITION TO CAPACITY: Foundations of Empowering Knowledge. Konferencen fokuserer på hvordan handlekraft opstår gennem viden, og hvordan denne handlekraft kan styrkes og understøttes gennem tværfagligt og tværsektorielt samarbejde.

Årets tema er FROM COGNITION TO CAPACITY: Foundations of Empowering Knowledge. Konferencen fokuserer på hvordan handlekraft opstår gennem viden, og hvordan denne handlekraft kan styrkes og understøttes gennem tværfagligt og tværsektorielt samarbejde.

Adelina conducted a teaching experiment using figure construction to make student reasoning explicit and support integrative understanding of metabolic pathways.

FNUG og NAFA inviterer til NiSE-webinar