Asymmetric Rydberg blockade of giant excitons in Cuprous Oxide

Marc Aßmann,Stefan Scheel,Manfred Bayer,Thomas Pohl,Valentin Walther,Julian Heckötter

doi:10.1038/s41467-021-23852-z

Abstract

The ability to generate and control strong long-range interactions via highly excited electronic states has been the foundation for recent breakthroughs in a host of areas, from atomic and molecular physics to quantum optics and technology. Rydberg excitons provide a promising solid-state realization of such highly excited states, for which record-breaking orbital sizes of up to a micrometer have indeed been observed in cuprous oxide semiconductors. Here, we demonstrate the generation and control of strong exciton interactions in this material by optically producing two distinct quantum states of Rydberg excitons. This is made possible by two-color pump-probe experiments that allow for a detailed probing of the interactions. Our experiments reveal the emergence of strong spatial correlations and an inter-state Rydberg blockade that extends over remarkably large distances of several micrometers. The generated many-body states of semiconductor excitons exhibit universal properties that only depend on the shape of the interaction potential and yield clear evidence for its vastly extended-range and power-law character.

Highlights

The ability to generate and control strong long-range interactions via highly excited electronic states has been the foundation for recent breakthroughs in a host of areas, from atomic and molecular physics to quantum optics and technology
In the field of quantum optics, the strong mutual interactions between Rydberg states can mediate enhanced optical nonlinearities even between single photons[9,10], which leads to the realization of a wide range of applications in quantum information processing[11,12]
The Rydberg blockade can be traced back to the asymptotic interaction between neutral particles, such as atoms or excitons, which is dominated by the van der Waals potential that decreases as a simple power law, V(r) = C6/r6, with the interparticle distance r

Summary

Introduction

The ability to generate and control strong long-range interactions via highly excited electronic states has been the foundation for recent breakthroughs in a host of areas, from atomic and molecular physics to quantum optics and technology. A prominent example of the underlying interaction mechanism is the case where the presence of one excited particle can perturb or even prevent the excitation of another by shifting its energy via the interaction between the two Rydberg states This Rydberg blockade[13] enables rapid saturation at very low light intensities[14,15,16], but can lead to the emergence of strongly correlated many-body states of Rydberg excitations[17,18]. The drastic increase of C6 ~ n11 with the principal quantum number n of excited states, on the other hand, gives rise to exaggerated van der Waals interactions that can be sufficiently strong to even affect the very process of optically generating highlying Rydberg states, as observed and exploited in cold-atom systems

Methods

Results

Conclusion