Swedish Physics Days 2025 in Luleå

13 Aug 2025, 09:00 → 15 Aug 2025, 18:00 Europe/Zurich

Luleå

 

 

 

Please find more information about the Swedish Physics Days 2025 at the conference homepage.

Here, in the menu to the left, you can find

1. schedule (continuously updated)
2. abstract submission
3. book of abstracts (continuously updated)

 

 

 

Wednesday 13 August

09:00 → 10:40 Section for condensed matter physics and nanophysics

09:00 → 10:40 Section for education - Presentations and discussion forum

09:00 Bedömningsstöd i fysik - digitala nationella prov

Bedömningsstöden i fysik ska digitaliseras, även om de ända sedan 1990-talet har levererats digitalt. Det som blir nytt är att proven ska levereras digitalt till eleverna och de ska genomföra dem via datorn, åtminstone vissa delar.

På samma sätt som för de nationella proven har syftet varit att effektivisera och göra proven mer likvärdiga. Effektiviseringen handlar främst om att det inte längre är nödvändigt att kopiera elevmaterial och att resultatrapporteringen sker i och med att bedömningen görs i provplattformen. Likvärdigheten handlar om att i ett digitalt system finns det möjligheter att göra olika typer av anpassningar så att i princip alla elever kan genomföra proven men även att alla provtagare har samma typ av digitala verktyg.

I presentationen kommer jag att berätta om skälen till de förändringar som redan genomförts så som rak poängsättning, ökning av antalet flervalsfrågor och den teoretiska laborationen, men även vad som kommer att ske när proven blir digitala.

Speaker: Anna Lind Pantzare (Umeå universitet)

11:00 → 11:45 Plenary lecture

11:00 Quantum Computing Based on Superconducting Qubits

Quantum computers are anticipated to solve certain computational tasks much faster than classical computers. In this talk, I will discuss the origins of quantum computing, explain the challenges involved in building a quantum computer, and explore their potential applications.

The fundamental building block of a quantum computer is the qubit, an individual quantum system that can exist in a superposition of two states. This means a single qubit can represent both 0 and 1 simultaneously. Consequently, a register of $N$ qubits can represent 2$^N$ numbers simultaneously, enabling massive parallelism that can be harnessed for simulation and computation.

Qubits can be realised using various technologies. In this talk, I will focus on computers built from superconducting qubits and describe the quantum computer that is being built at Chalmers.

Speaker: Prof. Per Delsing (Chalmers University of Technology)

11:45 → 13:00 Lunch

13:00 → 13:45 Plenary lecture

13:00 Molecular spectroscopy with optical frequency combs

Optical frequency combs are lasers whose spectra consist of hundreds of thousands of evenly spaced narrow lines spanning a broad spectral range. This unique combination of high spectral resolution and wide bandwidth has revolutionized molecular spectroscopy. Our group uses frequency combs to probe the energy level structure of molecules relevant to astrophysics, such as methane - the first organic molecule detected in the atmosphere of a hot-Jupiter exoplanet. The vibrational energy level structure of this small polyatomic molecule is complex and remains incompletely characterized. I will show how frequency comb double-resonance spectroscopy combined with ab initio calculations provides unique information about highly excited vibrational levels of methane, which is essential for modeling of high-temperature spectra observed in astrophysics.

Speaker: Prof. Aleksandra Foltynowicz (Umeå University)

14:00 → 16:00 Section for atomic, molecular and optical physics: (Chair: Aleksandra Foltynowicz, Umeå University)

14:00 Welcome and short introduction

Speaker: Aleksandra Foltynowicz (Umeå University)

14:15 Keynote: Laser Remote Microscopy for Insect Diversity Assessment

Recent insect decline prompts rapid online monitoring solutions with specificity for thousands of coexisting species. I demonstrate how microscopic and nanoscopic features of insects can aid differentiation of species and be retrieved with spectral lidar.

Speaker: Mikkel Brydegaard (Lund University, Norsk Elektro Optikk)

15:00 From ion chemistry and isomers on Titan to defence analysis for military applications

As of May 2025, 333 molecules are listed in the Cologne Database for Molecular Spectroscopy as having been detected in space. Of these molecules, there are oxygen-, nitrogen-, and metal bearing compounds, there are both neutrals and charged species as well as isomers and detection of these compounds are being made in a variety of environments. Thus, space is a rich and complex environment in which molecular chemistry plays an important role. However, the formation and destruction pathways of many of these compounds are still largely unknown. For proper assessment of the chemical networks in astronomical environments, such data is paramount to obtain. Isomers are of particular interest since their interconversion is usually hindered by an isomerization barrier unlikely to be overcome given the energy-scarce environments in space and they will readily act as two different molecules.

In this talk I will present the results obtained during my PhD: the selective generation of the two [CH$_3$N]$^ +$ isomers, H$_2$CNH$^+$ and HCNH$_2^+$, and their reactivity with a range of hydrocarbons and methanol as well as their infrared-predissociation spectrum. The two isomers have both been proposed to exist on the Kronian satellite Titan and to contribute to the observed chemistry there.

The results show that these reactions do lead to formation of heavier compounds, in barrier-free, exoergic, processes feasible to occur in cold, energy-scarce environments and that their reactivity is isomer-dependent. The obtained infrared-predissociation spectrum could very like contribute to a future detection of these isomers using infrared detection methods.

In the second half of my talk, I will briefly present my post-PhD career as an analyst and technical generalist at the Swedish Defence Research Agency and how the expertise gained from my PhD studies aids towards working for a safer and more secure world.

Speaker: David Sundelin (FOI)

15:15 Raman spectroscopy for brain tumor detection: Photon-matter interactions as optical biomarkers in neurosurgery

Raman spectroscopy is a powerful, non-invasive method to analyze molecular structure through the inelastic scattering of photons. Inside the broader framework of coherent Raman techniques, spontaneous Raman remains as a clinically accessible and versatile approach. The intrinsic vibrational modes of molecular bonds allow the identification of biochemical differences between components; these spectral features act as optical biomarkers of biochemical and metabolic processes.

Thanks to advances in instrumentation, we explore Raman spectroscopy as a label-free diagnostic tool applied in neurosurgery, offering a new dimension of intraoperative feedback in neurosurgical procedures where tissue margins are often ambiguous. Particular attention is given to the spectral regions and band intensities most correlated with malignancy, as variations in lipid, protein, and nucleic acid content, those along with the use of statistical and machine learning techniques for automated tissue classification.

To overcome the inherent signal limitations of Raman scattering in biological samples, such as fluorescence background, baseline distortions, and inter-patient variability we employed a physics-informed machine learning approach. Spectral normalization was performed using quotient-based correction against independent reference signals to reduce instrumentation-induced multiplicative effects. A convolutional neural network, trained on simulated Raman data, was then used to denoise and enhance spectral quality while preserving fine chemical detail. These AI-assisted preprocessing steps enable robust extraction of tumor-specific optical signatures across heterogeneous brain tissue samples, paving the way for real-time, intraoperative classification in neurosurgical settings.

Raman analysis offers practical utility in the neurosurgical setting, particularly for delineating tumor boundaries and assisting in intraoperative decision-making. The ability to optically distinguish tumor from healthy parenchyma at a molecular level could improve the precision of surgical resections and may complement histopathological workflows and aid in real-time classification of brain tumor subtypes by capturing biochemical gradients across tumor margins might gain insights even into the metabolism of tumors.

By applying fundamental principles of atomic and molecular spectroscopy to a frontier biomedical challenge, have the translational potential of molecular optics not only to probe structure, but to understand and actively guide interventions actively supporting clinical and therapeutic strategies, highlighting the growing role of optical physics in medical contexts creating new pathways for interdisciplinary research at the intersection of photonics and biomedicine, converging in the development of accessible, hybrid clinical tools for multimodal optical diagnostics.

Speaker: Dirce Pineda Vazquez (Luleå tekniska universitet)

15:30 Nitric Oxide Diagnostics in Plasma Heated Gas using Laser Absorption Spectroscopy

Accurate and real-time detection of nitric oxide (NO) in plasma-assisted combustion systems is critical for optimizing burner performance and reducing NOx emissions. This work presents the development of a tunable diode laser absorption spectroscopy (TDLA) diagnostic for NO quantification in plasma-heated gas relevant to plasma burner environments.

A tunable diode laser operating near 5060 nm is directed through an experimental setup, including beam splitters, lenses, photodetectors and a 32 cm long cell (absorbing path) subsequently filled with different gas seeded with NO. Room-temperature tests revealed that the low absorption signal and high noise floor make it challenging to detect NO reliably in these conditions. However, the chosen NO transitions become significantly stronger at high temperatures (up to a few thousands kelvin) typical of plasma-assisted combustion. Further experiments have therefore been conducted at these elevated temperatures using the setup in (Alexey Sepman, Marcus Gullberg, and Henrik Wiinikka. Applied Physics B, 126(100), 2020.), which can withstand such conditions. In this configuration, the plasma burner is embedded in a 50 cm long diameter chamber whose circular base has a 12.5 cm diameter. The resulting NO quantitative diagnostics in plasma-heated gases will be confirmed by independent measurements using Fourier transform infrared spectroscopy (FTIR). First measurements indicate accuracy of about 15%.

Additionally, the presence of water vapor (H₂O), a common combustion byproduct, introduces critical spectral interference, highlighting the importance of careful line selection and identification, and interference correction in real combustion environments, which is very valuable for the combustion community. By referencing HITRAN/HITEMP databases (I. E. Gordon et al. Journal of Quantitative Spectroscopy Radiative Transfer, 277:107949, 2022), (L. S. Rothman, et al. Journal of Quantitative Spectroscopy Radiative Transfer, 111:2139–2150, 2010), absorption coefficients are to be identified for prospective high-temperature measurements. These advancements in sensor design set the stage for accurate, in-situ quantification of NO under realistic plasma burner conditions, offering a promising avenue for real-time emissions monitoring, improved burner design, and sustainable energy production.

Speaker: Aurélien Ivanoff (Luleå University of Technology)

15:45 Submitted talk

14:00 → 16:00 Section for education - Presentations and discussion forum

14:00 Presentation/rundabordssamtal: Om det pedagogiska samarbetet

För att stärka ungas lärande och bidra till en sammanhållen utbildningskedja är det viktigt att universitet och gymnasieskolor samverkar kring pedagogiska frågor. Ett sådant samarbete skapar ökad förståelse för respektive uppdrag, och kan minska den stress och osäkerhet som många elever upplever inför övergången till högre utbildning.

Samtidigt är universitetslärarens pedagogiska utbildningsnivå i allmänhet inte jämförbar med gymnasielärarens, varvid samtal och lokala initiativ blir avgörande för att utveckla undervisningen och främja ett kollegialt lärande vid en institution. När sådana samtal får ta plats i vardagen, och involverar lärare från gymnasieskolan, skapas utrymme för reflektion, erfarenhetsutbyte och långsiktig kvalitetsutveckling.

Men hur startar sådana forum?

Vid Fysiska institutionen på Lunds Universitet har ett sådant initiativ vuxit fram spontant. En grupp universitetslärare med begränsad pedagogisk erfarenhet träffas regelbundet under namnet “Junior teachers’ pedagogic discussion group” för att diskutera frågor de själva upplever som angelägna i sin undervisningsvardag. Samtalen förankras i erfarna kollegors kunskap, för att ge djup och kontinuitet. En angelägen aktivitet för dessa lärare har varit att möta gymnasielärare, för att i samspel med dessa få en större förståelse för fysikstuderandes bakgrund och det svenska utbildningssystemet som helhet.

Under första delen av seminariet berättar vi hur initiativet startat och utvecklats, och deltagarna bjuds in att själva reflektera kring frågor som gruppen behandlat. Senare delen ägnar vi åt aktiviteter där deltagarna inbjuds att t.ex. formulera egna ideer kring erfarenhetsutbyte mellan skola och universitet. Syftet är att inspirera till fler lokala samtalsforum där lärares erfarenheter tas tillvara – något som i längden stärker både individer, kollegier och studenters lärande.

Aktiviteterna leds av medarbetare vid Nationellt resurscentrum för fysik och LTH:s enhet för pedagogisk utveckling, CEE.

Speaker: Elisabeth Nilsson (Nationellt resurscentrum för fysik, Lunds universitet)

16:30 → 17:30 Lab tour

16:30 → 18:00 Poster session

18:30 → 21:00 Conference dinner

Thursday 14 August

09:00 → 10:30 Section for atomic, molecular and optical physics: (Chair: Magnus Gustafsson, Luleå University of Technology)

09:00 Boosting Carbonaceous Research using Advanced Light Sources in Lund

Carbon based materials play crucial roles across environmental, industrial, and cosmic domains. In astrophysics, these particles are fundamental to interstellar dust, affecting light absorption, scattering, and emission processes essential for star formation, planetary evolution, and the cosmic dust cycle. Conversely, carbonaceous aerosols produced from the incomplete combustion of hydrocarbons contributes to global warming and air pollution, underscoring its significant environmental impact. In laboratory settings, carbonaceous nanoparticles open exciting possibilities in materials science and nanotechnology. Their unique optical properties, including strong light absorption across a broad spectrum, tunable fluorescence, and high scattering capabilities, make them promising candidates for next-generation materials. Traditional techniques like chemical analysis or imaging are effective for deposited samples, but deposition may lead to structural modifications. This talk will explore how advanced light sources in Lund enable in-depth investigation of carbonaceous materials in the aerosol form, revealing their complex properties and formation processes, and in solid form, with careful consideration to minimize sampling and measurement artifacts.

Speaker: Kim Cuong Le (Lund University)

09:30 High-resolution laser spectroscopy based on Optical Parametric Oscillators

Studies of the atomic spectra through resonant laser excitation provide access to the nuclear structures. Interactions of the nuclear ground state with the electronic shell induce small perturbations in the atomic level structure, known as the hyperfine structure (HFS) and the isotope shift (IS). Precise measurements of these effects permit the extraction of the nuclear properties like the spin $I$, the magnetic dipole moment $μ_I$, the electric quadrupole moment $Q_s$, and changes in mean square charge radii $\delta ⟨r^2⟩$, all of which are closely related to the nucleus’ configuration and shape [1]. With atomic transitions of the valence electrons in the range of a few eV, these are accessible with lasers working in the visible wavelength range.

For high-resolution laser spectroscopy the optical linewidth needs to be sufficiently small to resolve the atomic lines up to the HFS but should not be much narrower than the resolution-limiting effect of the specific experimental setup in order to maximize the efficiency [2], as well as requiring enough power densities to drive the transition of interest, typically achieved by ns-pulsed lasers. For laser spectroscopy techniques such as collinear resonance ionization spectroscopy [3] (CRIS), the resonance peak linewidths are in the order of 40-70 MHz, [4] which is sufficient to resolve the HFS in most elements. Pulsed laser light with linewidth, measured as the full width at half maximum (FWHM), of less than 50 MHz has been reported [5] by the amplification of a cw-dye laser beam in a pulsed dye amplifier (PDA) and of 20 MHz [6] by injection-locking a titanium:sapphire (Ti:Sa) with a narrow-linewidth cw-Ti:Sa, at the cost of rather challenging experimental setups these are only limited by the tuning range of the medium.

As more exotic nuclides are accessible, new laser techniques are needed to produce adequate wavelengths, such as for fermium and nobelium, which have some transition lines between 333 nm [7] to 355 nm [8], wavelengths notoriously challenging to produce whilst maintaining power stability and optical narrow-band operation [9–11]. Although dye lasers and solid-state systems based on Ti:Sa crystals are still the predominantly used systems in the field of laser spectroscopy [3, 7, 12, 13], we demonstrated that an OPO-seeded PDA system has a comparable performance [14], providing optical linewidths in the order of 100 MHz [15], by measuring the HFS of the ground state transition at 328 nm for some neutron-rich silver isotopes.

As an outlook, a brief look into further implementations of the cw-OPO system is given by studying the HFS of Yb-173 and neutron-deficient silver isotopes with laser-induced fluorescence spectroscopy. Finally, an extension of the seeded amplification concept is given to replace the tuning limitation of the medium by proposing a complete solid-state cw-OPO seeded optical parametric amplifier (OPA), to generate narrow-band, high-energy pulses for high-resolution laser spectroscopy.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 861198 (LISA).

References
1. P. Campbell et al., Prog. Part. Nucl. Phys. 86, 127–180 (2016).
2. V. N. Fedosseev et al., J. Phys. G 44, 084006 (2017).
3. T. E. Cocolios et al., Nucl. Instrum. Methods Phys. Res., B 376, 284–287 (2016).
4. R. P. de Groote et al.,Phys. Rev. Lett. 115, 132501 (2015).
5. V. Mishin et al., Sov. Phys. JETP 66 (1987) 235.
6. M. Reponen et al., Eur. Phys. J. A 48, 1–15 (2012).
7. M. Laatiaoui et al., Nature 538, 495–498 (2016).
8. S. Allehabi et al., J. Quant. Spectrosc. Radiat. Transf. 253, 107137 (2020).
9. S. Raeder et al., Nucl. Instrum. Methods Phys. Res. Sect. B-beam Interactions With Mater. Atoms 463, 86–95 (2020).
10. M. Reponen et al., Nat. Commun. 12, 1–8 (2021).
11. M. Verlinde et al., Rev. Sci. Instruments 91, 103002 (2020).
12. R. Ferrer et al., Phys. Lett. B 728, 191–197 (2014).
13. B. A. Marsh et al., Nucl. Instruments Methods Phys. Res. Sect. B: Beam Interactions with Mater. Atoms 317, 550–556 (2013).
14. M. Urquiza-González et al., SPIE LASE vol. 12399 (2023), p. 123990M.
15. M. Urquiza-González et al., Zenodo (2022).

Speaker: Mitzi Urquiza (University of Gothenburg & Division HÜBNER Photonics)

09:45 H$_{\bf 3}^{\bf +}$ Formation through Roaming in Cyclopropane

Three-dimensional electron and ion imaging spectrometry is used to study the dynamics of gas-phase cyclopropane after inner-shell electron excitation. Cyclopropane is the simplest cyclic hydrocarbon, C$_3$H$_6$. In this study, one particular dynamic is presented. The formation of a H$_3^+$ ion togheter with a C$_3$H$_3^+$ ion from the cyclopropane dication C$_3$H$_6^{2+}$. The formation of a H$_3^+$ ion has been suggested to form from a roaming process [1]. A neutral H$_2$ moiety starts roaming around the doubly charged C$_3$H$_4^{2+}$ ion. The H$_2$ is stuck in a very shallow energy potential. After some time, the neutral moiety abstracts a proton, and then the H$_3^+$ is repelled away by Coulomb repulsion [2]. We utilise the measured momentum from incomplete fragmentation pairs to reveal the underlying process. The fragmentation of C$_3$H$_3^+$+H$^+$+H$_2$ occurs when C$_3$H$_4^{2+}$ dissociate before the H$_2$ moiety can abstract the proton. The correlation between the momentum of the fragments reveals that the H$_2$ moiety is indeed participating in a roaming process.

This experiment was carried out at the MAX IV Laboratory in Lund, Sweden, at the FlexPES beamline.

[1] D. Townsend $et$ $al.$, (2004), $Science$ 306, 1158-1161. DOI: 10.1126/science.1104386.
[2] Sung Kwon et al. (2023), $J.$ $Phys.$ $Chem.$ $A$ 127,41, 8633-8638.

Speaker: Ville Lindblom (Lund University)

10:00 Ab-initio cavity Born-Oppenheimer methods: How can strong light-matter coupling change chemistry?

When molecules are placed in a non-classical photonic environment present in optical or nanoplasmonic cavities, it is possible to form strong light-matter-coupled hybrid states called polaritons. Recent experiments show that this strong coupling between light and matter is capable of modifying chemical and physical properties and offers a possible novel approach to control chemical reactions. The situation in which the quantized cavity modes are coupled via their characteristic frequency to vibrational degrees of freedom of molecules is called vibrational strong coupling (VSC). In the VSC regime, the chemistry of a single electronic state (mostly the ground state) and its vibrational spectroscopy are influenced by the cavity interaction.

In this contribution, I will discuss how the ab initio Cavity-Born-Oppen-heimer-Hartree-Fock (CBO-HF) approach can be used to study the effect of VSC on the ground state properties of single molecules and small ensembles of such molecules [1]. Our ab-initio treatment allows us to study the interactions between single molecules mediated by the cavity. These interactions give rise to local strong-coupling effects that are likely to allow modification of chemical reactivity in the VSC context. Moreover, we observe local changes in both the permanent dipole moment and the static polarizability induced by collective effects under collective strong-coupling conditions in small ensembles.
As a next step, we implemented analytical gradients and numerical Hessians within the CBO-HF framework [2,3], allowing us to calculate vibro-polaritonic IR and Raman spectra in the harmonic approximation.

[1] T. Schnappinger et al., J. Phys. Chem. Lett., 14, 8024 (2023).
[2] T. Schnappinger et al., J. Chem. Theory Comput., 19, 9278 (2023).
[2] T. Schnappinger et al., J. Chem. Theory Comput. (2025).

Speaker: Thomas Schnappinger (Stockholm University)

09:00 → 10:40 Section for education - Presentations and discussion forum

09:00 En anledning till varför du som lärare (även i fysik) bör bry dig om AI för lärande

I den här föreläsningen vill jag visa varför det kan vara en god idé att som lärare börja använda AI som ett sätt att förstärka det vi redan försöker göra: förstå vad studenterna tänker, hjälpa dem att se sitt eget lärande, och skapa undervisning som går att utveckla i dialog. Jag kommer att utgå från språkmodeller som ChatGPT och visa konkreta exempel på hur de kan användas som ett slags extra uppsättning ögon och öron – inte för att ersätta läraren, utan för att hjälpa oss se sådant vi annars kanske missar. Även om du undervisar i fysik, eller just därför, finns det mycket att vinna på att förstå vad de här verktygen faktiskt kan göra – och vad de inte kan. Det handlar inte om teknik eller språkmodellernas extrapolerade kapacitet om 3 år. Det handlar om undervisning här och nu.

Speaker: Marcus Strömbäck Hjärne (Luleå tekniska universitet)

09:40 AI i fysikundervisning - Marcus Liwicki och Marcus Strömbäck Hjärne, Luleå tekniska universitet

11:00 → 11:45 Plenary lecture

11:00 The second AI revolution in fundamental science research

In 2012 machine-learning tools achieved paradigm-shifting performance in image classification, but 2012 was also the year when the LHC collider at CERN discovered the Higgs boson. For the first time, a new fundamental particle was discovered with explicit use of machine learning tools. While until then machine learning was frowned upon as a valid tool by the physics community, in 2012 -almost overnight- it became a necessary instrument for data analysis in fundamental science. I call that event the first AI revolution in fundamental science.

Today we are ready for a second revolution, which will allow artificial intelligence to assist in the E3design of the complex instruments required to investigate matter at the shortest distance scales, by providing means for continuous scanning of the very high-dimensional space of design solutions of particle detectors. In order for that to happen, physicists have to team up with computer scientists to create the necessary interfaces (simulation tools, dimensionality reduction methods, optimization algorithms). Of particular importance is the concept of co-design, where hardware and software are optimized together, avoid misalignments that reduce the final performance of the resulting data collection and reduction pipelines. In this presentation I will describe the state of the art in these activities.

Speaker: Dr Tommaso Dorigo (Istituto Nazionale di Fisica Nucleare)

11:45 → 13:00 Lunch

13:00 → 13:45 Plenary lecture

13:00 Attosecond lasers

Ultrafast cameras, using ultrashort light flashes, allow the capture of ultrafast motion. In atoms or molecules, attosecond light pulses are needed to capture the motion of electrons (1 as = 10$^{-18}$ s). This presentation will highlight the physics behind the generation and application of attosecond light pulses.

Speaker: Prof. Anne L’Huillier (Lund University)

14:00 → 16:00 Section for atomic, molecular and optical physics: (Chair: Michael Odelius, Stockholm University)

14:00 Exploring protein molecular diffusion with coherent X-rays

Understanding protein motion within the cell is crucial for predicting reaction rates and macromolecular transport in the cytoplasm. A key question is how crowded environments affect protein dynamics through hydrodynamic and direct interactions at molecular length scales . Using megahertz X-ray Photon Correlation Spectroscopy (MHz-XPCS) at the European X-ray Free Electron Laser (EuXFEL), based on the principle of correlation before aggregation [1], we investigated ferritin diffusion at microsecond time scales. Our results reveal anomalous diffusion, indicated by the non-exponential decay of the intensity autocorrelation function at high concentrations [2]. These findings offer new insights into the complex molecular motion in crowded protein solutions, with potential applications for optimizing ferritin-based drug delivery, where protein diffusion is the rate-limiting step.

1. Reiser, M. et al. Resolving molecular diffusion and aggregation of antibody proteins with megahertz X-ray free-electron laser pulses. Nat. Commun. 13, 5528 (2022).
2. Girelli, A. et al. Coherent X-rays reveal anomalous molecular diffusion and cage effects in crowded protein solutions. Submitted

Speaker: Dr Anita Girelli (Stockholm University)

14:30 X-ray Molecular Spectroscopy Studies for Radiotherapy Applications

The enhancement of radiotherapy efficacy through the introduction of high-Z atoms into cancerous tissues is a promising strategy for improving cancer treatment outcomes. A critical aspect of this strategy lies in understanding the complex molecular fragmentation that occurs following the initial ionization event. This presentation will cover recent advancements in this field, focusing on new experimental tools and recent findings that shed light on these fundamental damage mechanisms.
First, I will introduce a new experimental platform, the Trapped Ion SpectroScopy (TRISS) setup, currently in its commissioning phase. TRISS is a tandem mass spectrometer incorporating an Electrospray Ionization (ESI) source, an Omnitrap, and a Time-of-Flight (TOF) mass analyzer. I will present its current capabilities for studying molecular fragmentation using Collision-Induced Dissociation (CID) and Electron-Induced Dissociation (EID), while noting that its photodissociation capabilities for use with synchrotron radiation are under commissioning.
The presentation will then connect these instrumental developments to my PhD research on radiosensitization. I will discuss recent results from an experiment on iodinated DNA, performed at the P04 beamline at PETRA III, using a different ion trap setup. The data shows that by tuning the X-ray energy from below (4500 eV) to above (4900 eV) the iodine L-edge, we observe a significant increase in the fragmentation of the DNA. This result provides direct evidence that resonant absorption in the high-Z atom creates a localized cascade of electrons, leading to enhanced molecular damage. This principle is central to designing effective radiosensitizers, which, upon irradiation, can generate fragments and reactive species that selectively damage cancerous cells. TRISS is poised to become a key tool for extending these initial findings to a broader range of potential radiosensitizer molecules, ultimately advancing the development of more targeted and effective radiotherapy treatments.

Speaker: Ouassim Hocine Hafiani (Uppsala University)

14:45 Sub-5 fs pump-probe spectroscopy on strongly coupled exciton–cavity-polaritons

The dynamics of strongly coupled nano systems have been intensively studied, but investigations in the few-fs regime are so far not standard practice. However, many of the systems have dynamics calling for sub-10-fs resolution. We investigate the ultrafast dynamics of strongly coupled exciton–cavity polaritons using sub-5 fs visible light pulses at ambient conditions. The experiments employ a 11.5 nm thick WS2 multilayer embedded in a Fabry-Pérot microcavity on a silicon substrate. Degenerate pump-probe spectroscopy was used in reflection, incorporating a self-referenced probe to minimize shot-to-shot noise. The measurements reveal transient reflectivity dynamics on the 10 fs timescale, inaccessible to conventional Ti:Sapphire systems with pulse durations exceeding 30 fs. This unprecedented time resolution provides novel insights (Fig. 1) into the polariton formation process, coupling dynamics and lifetime in these systems. Power dependent investigations reveal the saturation behavior of the polaritons. These findings offer new perspectives on the early-stage evolution of exciton–polariton states in microcavities.

Speaker: Fritz Joshua Schnur (Umeå University)

15:00 Relativistic treatment of hole alignment and ultrafast photoionization in noble gases

Speaker: Rezvan Tahouri (Lund University)

15:15 Mutual neutralization with manipulated initial quantum level distributions

Mutual neutralization (MN) is a fundamental electron-transfer process that occurs when oppositely charged ions collide, resulting in the formation of neutral products. The Double ElectroStatic Ion Ring ExpEriment (DESIREE) at Stockholm University offers a cryogenic, ultra-high vacuum environment with long ion storage times and a merged-beam geometry, that is ideal for high resolution MN studies. In this work, we combine DESIREE’s capabilities with active quantum state control to investigate how the internal states of ions influence the MN process.
Our studies focus on two systems: (1) Na⁺/K⁺ + Si⁻, and (2) Ba⁺ + Au⁻.
In the Na⁺/K⁺ + Si⁻ system, we employed a continuous-wave laser at 900 nm to selectively photodetach metastable Si⁻ ions, effectively depleting the excited-state population while preserving the ground state. By comparing data with and without laser depletion, we quantified the role of excited Si⁻ states in the reaction.
In the Ba⁺ + Au⁻ system, laser-based optical pumping was used to both depopulate and selectively populate specific Ba⁺ metastable states. By varying the internal state populations, we placed all kinetic energy release spectra on a common relative scale, enabling direct comparison of state-specific MN contributions.
These results show how powerful it is to combine quantum-state preparation with sensitive coincidence detection in DESIREE. By carefully controlling the internal states of the ions and using high-resolution measurements, we were able to clearly see how different quantum states affect the mutual neutralization process. Our findings provide valuable experimental data that can improve theoretical models and deepen our understanding of low energy ion–ion interactions.

Speaker: Rachel Poulose (Stockholm University)

15:30 Broadening of rotational CO lines by H$_\bf{2}$ or He collisions at low temperatures

The carbon monoxide (CO) molecule is the most abundant polar molecule in the Universe. This makes it easy to detect, and it plays a big role in research on various environments, such as in the interstellar medium and in stellar as well as planetary atmospheres. The CO spectrum is extensively studied in laboratory experiments, as well as theoretically and computationally. With hydrogen and helium (He) being the two most abundant elements in the Universe, collisional broadening of CO rotational spectral lines by hydrogen molecules (H$_2$) and by He is of great importance. The established impact theory may be implemented with close-coupling scattering calculations of the two-body collisions [1] using state of the art potential energy surfaces, e.g. [2, 3], for the H$_2$/He-CO pair. At room temperature, and down to tens of kelvins, those calculations provide broadening and shift parameters that are in satisfactory agreement with laboratory experiments [4, 5]. However, at temperatures of a few kelvins there are discrepancies on the order of a factor of two (see Figure 1). In this work we propose a computational approach that goes beyond the standard impact approximation and accounts for the finite duration of collisions. This way intracollisional effects are taken into account, which may affect the broadening of spectral lines and their symmetry. The approach has an electric dipole coupling with the electromagnetic field included in the scattering Hamiltonian. The method was originally developed by Julienne [5] and it has been successfully used, e.g. for weak dipole transitions and their interference with broad collision-induced spectra in HD-He mixtures [6].

Figure 1. Pressure broadening cross section for the R(0) transition of CO in collisions with He. Calculations from Ref. [1] and present work compared with experimental data [5].

[1] F. Thibault, et al., J. Mol. Spectr., 246, 118 (2007).
[2] A. Faure, P. Jankowski, T. Stoecklin, and K. Szalewicz, Scientific Reports 6, 28449 (2016).
[3] G. C. McBane, J. Mol. Spectr. 330, 211 (2016).
[4] M. Mengel, D. C. Flatin, and F. C. De Lucia, J. Chem. Phys. 112, 4069 (2000).
[5] M. M. Beaky, et al., J. Chem. Phys. 105, 3994 (1996).
[5] P. S. Julienne, Phys. Rev. A 26, 3299 (1982).
[6] M. Gustafsson and L. Frommhold, J. Chem. Phys. 115, 5427 (2001).

Speaker: Magnus Gustafsson (Luleå University of Technology)

15:45 Submitted talk

14:00 → 16:00 Section for education - Presentations and discussion forum

14:00 Workshop om mätfelsbehandling på gymnasienivå

I Gy25 inkluderas felberäkningar uttryckligen i fysikens ämnesplan. Hur kan vi som gymnasielärare hjälpa elever att förstå och hantera mätfel och felberäkningar på ett sätt som är meningsfullt och som utvecklar förståelsen för experimentellt arbete? I denna interaktiva workshop för fysiklärare på gymnasiet fördjupar vi oss i mätfel som ett centralt men ofta utmanande område inom fysikundervisningen.

Utgångspunkten är att mätfel inte bara är ett tekniskt inslag i laborationer, utan en viktig del av elevernas förståelse för fysik som vetenskap. Vi diskuterar skillnaderna mellan precision, riktighet och noggrannhet, och vad det innebär att resultaten ”stämmer” – både med varandra och med ett förväntat värde. Genom praktiska exempel och diskussioner kring autentiska elevlösningar undersöker vi olika metoder för att uppskatta mätfel: medelvärdesberäkning, variationsbredd, standardavvikelse samt felpropagering vid addition, subtraktion och multiplikation. Särskild vikt läggs vid hur vi kan hjälpa elever att tolka och jämföra mätserier, rita och analysera grafer samt bedöma sina egna resultat.

Målet är att deltagarna ska få konkreta verktyg, exempel och diskussionsunderlag som kan användas direkt i klassrummet – och som kan bidra till en mer reflekterande och undersökande laborativ praktik hos eleverna. Workshopen leds av medarbetare från Nationellt resurscentrum för fysik vid Lunds universitet.

Speakers: Lukasz Michalak (Nationellt resurscentrum för fysik, Lunds universitet), Elisabeth Nilsson (Nationellt resurscentrum för fysik, Lunds universitet), Lena Claesson (Nationellt resurscentrum för fysik, Lunds universitet)

16:30 → 17:15 Plenary lecture

16:30 Can You Game Your Way to Knowledge?

There are many ways to learn, and one of the more modern approaches is gamification. Erik Elfgren, Associate Professor of Energy Engineering and appointed Excellent Teacher at Luleå University of Technology, asks the question: Is it possible to game your way to a physics education? How can gamification be used to increase motivation and improve learning? What are its advantages and disadvantages? Erik also shares his system of bonus assignments.

Speaker: Prof. Erik Elfgren (Luleå University of Technology)

17:30 → 18:00 Swedish physical society annual meeting

18:00 → 18:45 Oseen medal award and presentation

Friday 15 August

09:00 → 10:40 Section for condensed matter physics and nanophysics: (Chair: Elizabeth Blackburn, Lund University)

09:00 Keynote: From the fundamentals of contact-electrification to a disruptive energy technology – the triboelectric nanogenerator

Triboelectric nanogenerator (TENG) was invented by Wang’s group in 2012, which is based on the coupling of triboelectrification and electrostatic induction effects for converting mechanical energy into electric power. TENG is playing a vitally important role in distributed energy and self-powered systems, with applications in the Internet of Things, AL, environmental/infrastructural monitoring, medical science, environmental science, and security. TENG is most effective for the utilization of high-entropy energy, which is the random, low-density, low-grade mechanical energy widely-distributed in our living environment and in nature. There are now over 20,000 scientists distributed in 90 countries and regions around the globe who have published papers on TENG. This presentation will first focus on the advances in fundamental science made due to the discovery of TENG both in chemistry and physics. Then we will focus on the technological and industrial impacts that have been made by TENG. We will show how this new invention will benefit to the sustainable development of humankind.

Speaker: Zhonglin Wang (Georgia Institute of Technology, US. and Beijing Institute of Nanoenergy and Nanosystems, China)

09:45 Submitted talks

09:00 → 10:40 Section for education - Presentations and discussion forum

09:00 Engaging Students in Physics: Interactive Demonstrations and Peer-Led Teaching Strategies

The statement “Teachers who make physics class boring are criminals”, attributed to physicist and educator Walter Lewin, carries a powerful message: educators have a responsibility to make physics engaging and inspiring. While not meant literally, the quote highlights the disservice done when the subject’s inherent beauty and excitement are lost through uninspired teaching. As physics educators, we must continuously reflect on how we can inspire our students to engage with the subject, foster their motivation to explore its applications in everyday life, and help them deeply understand and apply core concepts in every lecture we deliver.

In this talk, I will share two pedagogical approaches: interactive demonstration lectures and peer-led teaching that I have developed and implemented in higher physics education at Lund University over the past four years. These methods place students at the center of the learning process, promoting active participation, curiosity, and collaboration. Both approaches have been highly appreciated by students and colleagues alike, and they have proven effective in sparking students' interest and supporting deeper, more meaningful learning.

Speaker: Kim Cuong Le (Lund University)

09:20 Workshop för lärare kring fysikinnehåll, didaktik/allmän/teknik/läroböcker

11:00 → 11:45 Plenary lecture

11:00 Post-Li batteries: An atomistic perspective

Li-ion batteries are dominating the market for high-performance batteries. However, so-called post-Li batteries in which Li is replaced by other charge carriers such as Na, K, Mg, Ca, Al and even Cl offer the potential for competitive energy densities, but being significantly more abundant. In this talk, I will give an overview over the advantages and also obstacles associated with post-Li batteries. I will also present successful research efforts improving the performance of post-Li batteries, often achieved by a close collaboration between experiment and theory on the atomic level.

Speaker: Prof. Axel Groß (Ulm University)

11:45 → 13:00 Lunch

13:00 → 13:45 Plenary lecture

13:00 Trapping particles: From research on anti-matter to teaching experimental physics in high-schools

We will in this talk describe and demonstrate the basic principles of traps with a discussion of similarities and difference between optical traps, acoustic traps and electro-magnetic traps. We will give examples of current research where traps are used, with trapping of antihydrogen as the most striking example. The presentation will also discuss various pedagogical suggestions on how traps can be used to demonstrate fundamental physical quantities and how this can be applied in upper secondary schools or in undergraduate classrooms. As examples, we will demonstrate charge quantization and how acoustic traps can be used to demonstrate wave physics.

Speakers: Dr Fredrik Olof Andre Parnefjord Gustafsson (CERN), Dr Jonas Enger (University of Gothenburg)

14:00 → 17:30 Excursion