New quantum technology combining free electrons and photons

Quantum technology has the potential to revolutionize our lives, much like the inventions of computers and the internet did: faster computers, eavesdropping communications, better car sensors. Experts around the world are trying to implement the results of basic research into quantum technology. For this purpose, individual particles such as photons (subatomic particles of light) often need to have tailored properties.

However, obtaining individual particles is complex and requires complex methods.A study recently published in the journal chemistryresearchers now present a new method to simultaneously generate two individual particles in the form of pairs.

Fundamentals of Quantum Physics in Electron Microscopy

An international team from the Max Planck Institute (MPI) in Göttingen, the University of Göttingen and the Swiss Federal Institute of Technology in Lausanne (EPFL) has successfully combined a single free electron with a photon in an electron microscope. In the Göttingen experiment, a beam from an electron microscope passes through an integrated optical chip manufactured by a Swiss team. The chip consists of fiber optic coupling and a ring-shaped resonator that stores light by keeping photons moving on a circular path.

“When electrons scatter in an initially empty cavity, photons are created,” explains MPI scientist Armin Feist, one of the study’s first authors. “In the process, the electron loses exactly the amount of energy needed for a photon to be created from virtually nothing in the cavity. As a result, the two particles are bound by interaction, They form pairs.” Improved measurement methods have allowed physicists to accurately detect the individual particles involved and their co-occurrences.

Future quantum technology with free electrons

“For an electron-photon pair, just measuring one particle gives us information about the energy content and temporal appearance of the second particle,” says Germaine Arend, Ph.D. She is an MPI candidate and lead author of the study. This allows the researcher to use one quantum particle in her experiments while at the same time confirming its existence by detecting other particles in a so-called heralding scheme. Such capabilities are necessary for many applications of quantum technology.

Claus Ropers, Director of Max Planck, sees electron-photon pairs as a new opportunity for quantum research. “This method opens up exciting new possibilities for electron microscopy. In the field of quantum optics, entangled photon pairs are already improving imaging. ,” says Roper.

EPFL professor Tobias Kippenberg adds: .”