13 Nov 2026
Researchers at LMU Munich and the MPQ have built a platform that combines two capabilities previously developed only separately: enabling single atoms to exchange information with light and letting atoms interact with one another in a controlled way.
© Thorsten Naeser
Future quantum computers may not operate as isolated machines, but as networks of processing nodes linked by light. Such networks require individually controlled atoms that store quantum information, interactions between atoms that enable quantum computations, and an efficient way to exchange quantum information between atoms and particles of light, so-called photons. Until now, combining these functions in a single device has remained an open challenge.
Optical Resonator
A team led by Johannes Zeiher, Professor of of Experimental Physics – Synthetic Quantum Matter, group leader at the Max Planck Institute of Quantum Optics (MPQ), and member of the Munich Center for Quantum Science and Technology (MCQST), has now achieved an important breakthrough.
In their experiment, individual rubidium atoms are held in an array of optical tweezers, tightly focused laser beams that act as tiny traps. To enable the atoms to exchange information with light, the array is placed inside an optical cavity – two highly reflective mirrors facing each other. A photon entering the cavity bounces back and forth between the mirrors thousands of times, repeatedly passing through the atoms. This greatly strengthens the otherwise weak interaction between a single atom and a photon.
For future quantum computations to work, however, the atoms must also interact with one another. To achieve this, they are excited to so-called Rydberg states. In these highly excited states, atoms interact strongly with their neighbors even over distances of several micrometers, thousands of times larger than the atoms themselves. These interactions are essential for elementary logic operations, known as quantum gates, in neutral-atom quantum computers. Continue