Quantum in Lund meting

Time-Dependent Strong-Coupling Phenomena at XUV Wavelengths

Following the presentation, a general discussion about quantum-related topics in Lund will take place.

As always, there will be Fika.

Abstract:

Recent advances in free-electron laser (FEL) technology have intensified interest in coherent light-matter interactions in the extreme ultraviolet (XUV) regime. Our group is working on theoretical ideas in this research field in close collaboration with experimentalists, c.f. Refs. [1,2]. The high intensity attainable by FEL pulses open up for previously inaccessible phenomena, such as dressed-atom stabilization [3], while the coherent nature of seeded FEL pulses opens up for ultrafast control of strong coupling in atoms and ions, which results in complex absorption and fluorescence patterns [4]. In this talk, I will discuss how “time symmetry” of FEL pulse envelopes can be harnessed to control entanglement in photoionization [5]. Further, I will show how such envelopes can be used to reveal entanglement transfer from an electron-ion pair in photoionization, to an electron-photon pair in fluorescence [6]. Our calculations of time-dependent dynamics in composite electron-ion-photon systems pave the way for studies of time-resolved entanglement and coherent control in more complex systems in the future.

References:

[1] Nandi, S., Olofsson, E., Bertolino, M. et al. “Observation of Rabi dynamics with a short-wavelength free-electron laser”. Nature 608, 488–493 (2022). DOI: 10.1038/s41586-022-04948-y

[2] Nandi, S., Stenquist, A., Papoulia A., et al. “Generation of entanglement using a short-wavelength seeded free-electron laser”. Sci. Adv. 10, eado0668 (2024) DOI: 10.1126/sciadv.ado0668

[3] Olofsson, E., and Dahlström, J. M. “Photoelectron signature of dressed-atom stabilization in an intense XUV field”. Phys. Rev. Research 5, 043017 (2023) DOI: 10.1103/PhysRevResearch.5.043017

[4] Stenquist, A., Zapata, F., Olofsson, E., et at. “Mollow-like triplets in ultrafast resonant absorption”. Phys. Rev. Lett. 133, 063202 (2024) DOI: 10.1103/PhysRevLett.133.063202

[5] Stenquist, A., and Dahlström, J. M. “Harnessing time symmetry to fundamentally alter entanglement in photoionization”. Phys. Rev. Research 7, 013270 (2025) DOI: 10.1103/PhysRevResearch.7.013270

[6] Stenquist, A., Bruhnke, J. N., Zapata, F., and Dahlström J. M. “Entanglement transfer in a composite electron-ion-photon system”. Rep. Prog. Phys. 88, 080502 (2025) DOI: 10.1088/1361-6633/adf354