Light-matter control of quantum materials

In our group we investigate materials interacting with light in ways that can probe and modify key materials properties.

Our goals:

  • explore nonthermal pathways to ultrafast control of quantum materials (review article here)
  • investigate cavity control of quantum materials (for a simple explanation see press release here)
  • develop methods to simulate nonequilibrium light-matter coupled quantum many-body systems (slides here)
  • guide pump-probe experiments and time-resolved spectroscopy to help functionalize nonequilibrium matter

Dynamics of ordered phases

One thread of our research is dedicated to dynamics of emergent ordered phases in complex materials. These interesting phases comprise superconductors, charge- and spin-density waves or excitonic condensates. Below you see an animation showing how a sequence of light pulses with specific polarizations can rotate an entire chiral condensate (a two-dimensional topological superconductor) from right-handed to left-handed. We envision that this could be used for quantum information processing with chiral Majorana fermions.

Optical rotation of a Bloch vector from a d+id (right-handed) to d-id (left-handed) topological superconductor. [click image to play gif]
© Martin Claassen

Cavity quantum materials

Cavity quantum-electrodynamical environments can affect materials with pure quantum fluctuations of light. This is used to change properties of molecules and chemical reaction pathways in nanoplasmonics and polaritonic chemistry. We have recently proposed to also use it for cavity materials science to change fundamental couplings that critically affect materials properties. The image below shows an illustration.

The vacuum fluctuations of light (yellow wave) are amplified in an optical cavity (upper and lower reflecting mirrors). Crystal lattice vibrations (red atoms) at a two-dimensional interface surf this strong light wave. The thus mixed light-vibrational waves couple particularly strongly to electrons in a two-dimensional atomically thin material (green and yellow atoms), changing its properties.
© Jörg M. Harms / MPSD