News Overview

Scientists at Hei­del­berg Uni­ver­si­ty have achieved a groundbreaking milestone in quan­tum physics: the creation of a Laughlin fractional quan­tum Hall state using just two ultracold fermions.

“The whole is greater than the sum of its parts” – this phrase often attributed to Aristotle captures the essence of one of the most intriguing phenomena in nature: emergence. When several parts of a physical system interact, new properties can arise that its single parts do not have on their own. A striking example is the collective behaviour of quan­tum many-body systems,  which can produce novel effects like low-energy excitations carrying a fraction of an electron's charge.

Researchers from the group of STRUCTURES' principal investigator Prof. Selim Jochim at Hei­del­berg Uni­ver­si­ty, in collaboration with Philipp Preiss from LMU Munich, have made significant progress in understanding the emergence of fractional charges. By trapping and spinning a single pair of ultracold lithium-6 atoms in optical tweezers, they replicated the topological properties of this exotic state, previously seen only in bosonic systems. Using a tailored rotation to mimic the influence of a magnetic field, they achieved a strongly correlated atomic state described by physicist Robert Laughlin's wave function for the fractional quan­tum Hall effect, characterized by its collective and topological nature.

This accomplishment marks a crucial step in the study of emergence of topological phases of matter and paves the way to exploring more complex states, such as quan­tum Hall ferromagnetism and topological p-wave superconductors.

Further information:

• Publication 1: P. Lunt, P. Hill, J. Reiter, P. M. Preiss, M. Gałka, S. Jochim, Phys. Rev. Lett. 133, 253401 (2024)
• Publication 2: P. Lunt, P. Hill, J. Reiter, P: M. Preiss, M. Gałka, S. Jochim, Phys. Rev. A 110, 063315 (2024)
• APS Physics Viewpoint Article: Ultracold Fermions Enter the Fractional Quan­tum Hall Arena
• Selim Jochim's group