From quantum geometry to Fisher information

• Gunnar Felix Lange (UiO)

Room: Tellefsens Tårn Quantum sensing relies on an unknown parameter being encoded in a quantum state, which is read out and measured. One interpretation of this encoding is geometrically, where we consider the quantum system to live on a space parameterized by the parameter. The distance on this space is then linked to the Fisher information, giving the maximal attainable sensitivity of the sensor. This gives a close relation between the quantum geometric tensor and the quantum Fisher information. In this talk, I will briefly review this connection, and then talk about how topology constrains geometry, and therefore in turn constrains quantum sensing.

Modeling superconducting-qubit processors and simulators beyond 100 qubits

• Simon Pettersson Fors (Chalmers)

Room: Tellefsens Tårn As superconducting quantum processors scale beyond 100 qubits, new theoretical tools are required to model their complex, many-body dynamics. In this talk, we introduce a scalable, non-perturbative renormalization method using continuous unitary transformations to systematically derive effective Hamiltonians. This method efficiently eliminates weakly coupled degrees of freedom, capturing the essential physics of large systems while maintaining polynomial memory scaling with system size, a key advantage shared with methods like tensor networks. We apply this method to a two-dimensional array of transmons with tunable couplers. In particular, we analyze the emergence of long-range couplings, quantifying how ZZ and effective qubit-qubit interactions scale across the array. This work provides an efficient and scalable tool for modeling these critical interactions in many-mode quantum systems, directly aiding the design of future superconducting processors and simulators.

Doping-induced quantum spin liquids: Towards robust topological order for quantum technology

• Cecilie Glittum (UiO)

Room: Tellefsens Tårn Quantum spin liquids provide a natural platform for robust topological order and fractionalised excitations, but realising such phases in realistic quantum magnets has remained a long‑standing challenge. In this talk, I will introduce the concept of quantum spin liquids, and show how dilute hole doping of a half‑filled Mott insulator on corner‑sharing tetrahedral lattices leads to a quantum spin liquid with clear spin–charge separation in simple Hubbard‑type models.

Generation and Characterization of Nonclassical Light for Quantum Technology

• Kishore Thapliyal (UiO)

Room: Tellefsens Tårn Quantum enhancement in computation, communication, and sensing relies on the generation and control of nonclassical states. Generation of such photonic nonclassical states useful for quantum technology is discussed in the context of quantum state engineering and reservoir engineering. Quadratic Hamiltonians generate and preserve Gaussian states, whose dynamics are completely determined by the first and second moments of the canonical bosonic operators. There are numerous applications of the Gaussian states, but their capabilities are fundamentally limited. Achieving stronger nonclassical properties and quantum advantage requires quantum state engineering or reservoir engineering. As an example of the former case experimental generation of non-Gaussian states after photon addition and subtraction is discussed [1]. Such states are shown to possess photon-number fluctuations in twin beams as well as the corresponding signal and idler beams below the classical limit. These engineered states provide a versatile and experimentally accessible platform for the direct comparison of different quantum operations aimed at producing highly nonclassical and entangled states. Potential of reservoir engineering for singularity enhanced quantum sensing is illustrated by an example of two-mode Gaussian state [2]. The presented framework provides practical guidelines for engineering nonclassical and non-Gaussian states in platforms relevant to quantum communication, sensing, and information processing. [1] K. Thapliyal, J. Peřina Jr., O. Haderka, V. Michálek, and R. Machulka, Experimental characterization of multimode photon-subtracted twin beams, Phys. Rev. Res. 6, 013065 (2024). [2] K. Thapliyal, J. Peřina Jr., G. Chimczak, A. Kowalewska-Kudlaszyk, A. Miranowicz, Multiple quantum exceptional, diabolical, and hybrid points in multimode bosonic systems: I. Inherited and genuine singularities, Quantum 9, 1932 (2025).

Quantum simulation with giant atoms

• Guangze Chen (Chalmers)

Room: Tellefsens Tårn Superconducting quantum processors require hardware platforms that combine scalability with flexible multi-qubit interactions. Here, we show how giant atoms, artificial atoms coupled to a waveguide at multiple spatially separated points, enable interference-engineered quantum interactions through phase-controlled coupling to propagating photons. By exploiting quantum interference, giant atoms can realize tunable interactions while operating at decoherence-free points. This mechanism enables the implementation of native multi-qubit gates without additional parametric couplers and naturally extends to scalable network architectures. Our results establish giant atoms as a scalable hardware platform for realizing native qubit interactions and multi-qubit gates for quantum simulation and quantum computation.

Nanophotonic Spectral Transduction for Reliable Readout of Local Molecular and Quantum Excitations

• Zhiyuan Hedlund (EPFL)

Room: Tellefsens Tårn Many molecular, nanoscale, and quantum systems are accessed experimentally through spectra. Spectral features such as peak position, linewidth, splitting, intensity ratio, and polarization dependence encode allowed transitions, coupling strengths, lifetimes, dephasing, selection rules, and local environmental perturbations. However, when these weak local excitations are read through a nanophotonic structure, the measured spectrum is no longer a simple property of the target system alone. It is shaped by the target excitation, the optical transducer, and, in some regimes, their hybrid light–matter response. My work addresses this measurement layer. I develop nanophotonic platforms that convert weak local molecular excitations into measurable nonlinear optical spectra, while defining the conditions under which these spectra can be interpreted, compared, and reused. In my doctoral work, I used dual-resonant plasmonic nanocavities as spectroscopy pixels for continuous-wave nonlinear mid-infrared vibrational readout. The key contribution was not only the observation of nonlinear signals, but the construction of a measurement framework: device qualification, resonance-informed spectral-window selection, fixed-geometry readout, and standardized fingerprint outputs. This logic naturally extends toward quantum nanophotonics and hybrid nanoscale systems. The central question becomes how to distinguish whether a spectral feature originates from the target excitation, cavity filtering, environmental perturbation, or genuine light–matter hybridization. By treating spectra as energy-resolved observables and nanocavities as engineered transducers, this approach can help extract physical parameters such as detuning, coupling strength, linewidth, dephasing, mode hybridization, and local environmental sensitivity. The broader goal is to make weak local excitations experimentally usable: not only observing spectral signatures, but turning them into reliable physical parameters that can be understood, engineered, and eventually used in molecular spectroscopy, quantum materials, nanoscale sensing, and hybrid photonic interfaces.

Experimental demonstration of non-local magic in superconducting quantum processor

• Jovan Odavić (University of Naples Federico II)

Room: Tellefsens Tårn Magic is a non-classical resource whose efficient manipulation is fundamental to advancing efficient and scalable fault-tolerant quantum computing. Quantum advantage is possible only if both magic and entanglement are present. Of particular interest is non local magic - the fraction of the resource that cannot be distilled (or erased) by local unitary operations - which is a necessary feature for quantum complex behavior. We perform the first experimental demonstration of non-local magic in a superconducting Quantum Processing Unit (QPU). Direct access to the QPU device enables us to identify and characterize the dominant noise mechanisms intrinsic to quantum hardware. We observe excellent agreement between theory and experiment after the inclusion of the dominant noise sources in our system and show the experimental capability of harnessing both local and non-local magic resources separately. This talk will be based on the recent preprint: arXiv: 2511.15576.

Thorlabs' Quantum Education Kits Room: Tellefsens Tårn

Panel discussion: transition from academia to industry Room: Tellefsens Tårn