Manipulating light to advance quantum entanglement research
by Robert Schreiber
Berlin, Germany (SPX) Sep 07, 2025

Two physicists from the University of Namur, Professor Michael Lobet and PhD student Adrien Debacq, are exploring the phenomenon of superradiance in near-zero refractive index materials, work that could transform the future of quantum computing. Their study, carried out with Harvard University, Michigan Technological University, and Sparrow Quantum, was published in Light: Science and Applications.

Superradiance, first described by Robert Dicke in 1954, occurs when atoms emit light more strongly in sync, similar to a choir singing in unison. Typically, this requires the emitters to be very close together. However, in near-zero index materials, that spatial limitation is lifted: the light field becomes uniform, enabling atoms to interact as though they were optically close even when separated.

This effect opens new avenues for quantum entanglement, a vital property for processing information in quantum systems. The Namur-Harvard-MTU team has theoretically designed a photonic chip using nitrogen vacancy diamonds that extends entanglement up to 17 times farther than possible in a vacuum. Such a system could be readily integrated into photonic chips, a first in the field.

"This is the first time that such a long range has been achieved using a compact system that can be easily implemented in photonic chips," said Professor Lobet. His team was joined by Harvard PhD student Olivia Mello and Sparrow Quantum's Dr. Larissa Vertchenko.

Harvard professor Eric Mazur emphasized that this work demonstrates how near-zero index photonics bridges classical electrodynamics and quantum mechanics. Entanglement, he noted, enables quantum information transfer, part of what is often called the "second quantum revolution."

Potential applications include next-generation lasers, highly sensitive sensors, and quantum-secure telecommunications. "Preserving the high degree of entanglement on chip over longer ranges may raise the possibility of multipartite entanglement involving many qubits," explained MTU Associate Professor Durdu Guney. This could accelerate advances in universal quantum computing and distributed quantum communication.

The next challenge is experimental validation. Researchers aim to miniaturize the system to microscopic scales, moving closer to practical quantum devices that could one day be as small as consumer electronics.

Research Report:Long-range quantum entanglement in dielectric mu-near-zero metamaterials.

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