Compact Quantum Light Processing: New Discovery Drives Advances in Optical Quantum Computing

An international collaboration of researchers led by Philip Walther of the University of Vienna has achieved a major breakthrough in quantum technology, successfully demonstrating quantum interference between multiple single photons using a new resource-efficient platform.This work was published in scientific progress Represents a significant advance in optical quantum computing, paving the way for more scalable quantum technologies.

Interference between photons is a basic phenomenon of quantum optics and the cornerstone of optical quantum computing. It involves exploiting the properties of light, such as wave-particle duality, to induce interference patterns to enable the encoding and processing of quantum information.

In traditional multiphoton experiments, spatial encoding is often employed, where photons are manipulated in different spatial paths to induce interference. These experiments require complex setups with a large number of components, which makes them resource-intensive and difficult to scale.

In contrast, an international team of scientists from the University of Vienna, the Politecnico di Milano and the Free University of Brussels opted for an approach based on time encoding. The technique manipulates the time domain of photons rather than their spatial statistics.

To implement this approach, they developed an innovative architecture using fiber optic loops at the Christian Doppler Laboratory at the University of Vienna. This design enables the reuse of the same optical components, thereby promoting efficient multiphoton interference with minimal physical resources.

First author Lorenzo Carosini explains: “In our experiments we observed quantum interference between up to eight photons, beyond the scale of most existing experiments. Thanks to the versatility of our method, the interference pattern can Reconfigurable, and the size of the experiment can also be reconfigured.

The results demonstrate that the implemented architecture is significantly resource efficient compared to traditional spatial encoding methods, paving the way for more accessible and scalable quantum technologies.