Imaging quantum many-body states

Low temperatures are a pre-requisite for the exploration of many quantum regimes of matter. This is the case because a condition must be reached where the energy associated with quantum fluctuations is substantially larger than thermal noise floor. Quantum fluctuations can then condense and new electronic ground states emerge. These often feature complex phase diagrams and unconventional characteristics, such as superconducting or non-Fermi liquid properties, or also non-Abelian statistics. More generally, many of these macroscopic quantum many-body states entail coherence and superposition of states which can be tuned by non-thermal external parameters, such as static magnetic fields or electromagnetic field pulses.

SLAC_CoherentLockIn_FeSe
Greg Stewart/SLAC National Accelerator Laboratory

The difficulty of combining low-temperature sample environments with photon experiments stems from the radiative heat input, particularly in pump-probe schemes where a sample is not only probed, but also excited by an electromagnetic field pulse. Consequently, only few possibilities exist world-wide for low-temperature, photon-based inspection of electronic states.

Our focus is to realize bespoke sample environments and combine them with novel measurement schemes at PSI’s accelerator-based lightsources, namely at SwissFEL and the Cristallina-Q endstation, for structural and spectroscopic studies deep in the quantum limit. We aim at using high magnetic fields and/or employing coherent driving protocols to directly image electronic quantum many-body states via time-resolved x-ray scattering.

Imaging ultrafast electronic domain fluctuations with X-ray speckle visibility
N. Hua, Y. Sun, P. Rao, N. Zhou Hagström, B. K. Stoychev, E. S. Lamb, M. Madhavi, S. T. Botu, S. Jeppson, M. Clémence, A. G. McConnell, S.-W. Huang, S. Zerdane, R. Mankowsky, H. T. Lemke, M. Sander, V. Esposito, P. Kramer, D. Zhu, T. Sato, S. Song, E. E. Fullerton, O. G. Shpyrko, R. Kukreja, S. Gerber
arXiv:2408.10050

Nonthermal pathways to ultrafast control in quantum materials
A. de la Torre, D. M. Kennes, M. Claassen, S. Gerber, J. W. McIver, M. A. Sentef
Rev. Mod. Phys. 93, 041002 (2021)

Femtosecond electron-phonon lock-in by photoemission and x-ray free-electron laser
S. Gerber, S.-L. Yang, D. Zhu, H. Soifer, J. A. Sobota, S. Rebec, J. J. Lee, T. Jia, B. Moritz, C. Jia, A. Gauthier, Y. Li, D. Leuenberger, Y. Zhang, L. Chaix, W. Li, H. Jang, J.-S. Lee, M. Yi, G. L. Dakovski, S. Song, J. M. Glownia, S. Nelson, K. W. Kim, Y.-D. Chuang, Z. Hussain, R. G. Moore, T. P. Devereaux, W.-S. Lee, P. S. Kirchmann, Z.-X. Shen
Science 357, 71 (2017)

CH-F Pulsed Magnet Retreat
•Fundamentals of Nature

Swiss-French pulsed magnetic field retreat

SwissFEL Materials research Quantum research

The Cristallina-Q team has welcomed French high-field experts at SwissFEL for an informal 2-day retreat. The ten participants  discussed which technical capabilities of the UZH-PSI pulsed magnet setup should be further developed and which science cases targeted in the upcoming commissioning and pilot experiment phase.

Cristallina 1st light
•Large research facilities

SwissFEL Cristallina "first light" milestone achieved

SwissFEL

First X-rays have reached the SwissFEL Cristallina experimental station on 14.03.2021 which is one day ahead of schedule. The achievement of this important milestone marks the beginning of the commissioning phase of the Cristallina project.

Cryo Stand
•Large research facilities

Diffractometer stand built in collaboration with local SME

SwissFEL Industry Relations

A light-weight, low-vibration diffractometer stand has been designed and produced in close collaboration with the local supplier Heinz Baumgartner AG. This component will be used in conjunction with a cryomagnet system to study quantum matter at the SwissFEL Bernina and Cristallina-Q endstations.

teaserbild.jpg

Scientists get first direct look at how electrons ‘dance’ with vibrating atoms

Scientists at the SLAC National Accelerator Laboratory and Stanford University - one of the leading authors, Simon Gerber, has in the meantime relocated to PSI - have made the first direct measurements, and by far the most precise ones, of how electrons move in sync with atomic vibrations rippling through an quantum material, in the present study an unconventional superconductor, as if they were “dancing" to the same beat.

•Future Technologies
•12 min

Research experience from California benefits Swiss X-ray free-electron laser SwissFEL

SwissFEL

An X-ray free-electron laser (XFEL) is capable of visualizing extremely fast structural and electronic processes. Pilot experiments will take place at the PSI's Swiss Free-Electron Laser (SwissFEL) from the end of 2017 on. Two current publications in Science and Nature Communications demonstrate the kind of outstanding scientific work that is enabled by such facilities. The work was carried out at the Linac Coherent Light Source (LCLS) in California. Two of the leading authors behind these studies have now relocated to the PSI in order to share their expertise as SwissFEL expands its capabilities.