Scientists discover new quantum realms with colorful entanglement

Experimental setup of the NOON-state interference. Credit: Light: Science & Applications (2024).

In the world of quantum physics, scientists have recently made a groundbreaking discovery called frequency-domain entanglement.

This fascinating development opens up new avenues in the realm of quantum technologies, which could potentially revolutionize how we process information and sense the world around us.

Quantum entanglement is a complex phenomenon where particles become interconnected, and the state of one particle instantly influences the state of another, no matter how far apart they are.

Traditionally, researchers have explored this concept through what’s called spatial-domain entanglement, which deals with particles following different paths.

This method has been pivotal in advancing high-precision measurements and developing quantum computing.

However, the latest research led by Professor Heedeuk Shin and his team at Pohang University of Science and Technology in Korea takes a different approach by using a tool called a frequency beam splitter.

This device uniquely manipulates the frequency—or color—of photons, which are particles of light. By changing the frequency of these photons, scientists can create entangled states not just along different paths, but between different colors within a single light beam.

The team’s innovative use of a frequency beam splitter has achieved a 50% success rate in altering photon frequencies, a significant step forward in quantum experiments.

They’ve demonstrated this new type of entanglement using a setup where two photons, one red and one blue, are merged and then split by the frequency beam splitters.

This setup allowed them to observe a phenomenon known as two-photon interference, which essentially doubles the resolution of measurements compared to using single photons.

Their experiments have successfully generated what’s known as a two-photon NOON state within a single-mode fiber—a fancy way of saying that two photons are entangled in such a way that they either both emerge at one frequency or another. This state allows for extremely precise measurements, surpassing traditional methods by a factor of two in terms of resolution.

This breakthrough not only provides a deeper understanding of quantum mechanics but also hints at exciting possibilities for the future.

For example, the ability to control photon frequencies so precisely could enhance quantum sensors and lead to more secure communication networks.

The discovery of frequency-domain entanglement marks a significant milestone in quantum research.

It paves the way for exploring new quantum technologies that harness the unique properties of light, potentially transforming everything from microscopic imaging to the security of data transmission across the globe.

Source: Chinese Academy of Sciences.