Entangled atoms cross quantum network from one lab to another

Platform for building quantum networks

The two quantum systems were set up in in two laboratories, one in the building that houses the Department of Experimental Physics and one in the building that houses the Institute of Quantum Optics and Quantum Information of the Austrian Academy of Sciences. "Until now, trapped ions were only entangled with each other over a few meters in the same laboratory. Those results were also achieved using shared control systems and photons (light particles) with wavelengths that aren't suitable for travelling over much longer distances," Ben Lanyon explains. After years of research and development, the Innsbruck physicists have now managed to entangle two ions across campus. "To do this, we sent individual photons entangled with the ions over a 500-meter fiber optic cable and superimposed them on each other, swapping the entanglement to the two remote ions," says Tracy Northup, describing the experiment. "Our results show that trapped ions are a promising platform for realizing future distributed networks of quantum computers, quantum sensors and atomic clocks."

Ben Lanyon's and Tracy Northup's teams are part of the Quantum Internet Alliance, an international project under the European Union's Quantum Flagship. The latest results have been published in Physical Review Letters. The research was financially supported by the Austrian Science Fund FWF and the European Union, among others.