Quantum-entangled light from a vibrating membrane

Quantum Network:

Entanglement, a powerful form of correlation among quantum systems, is an important resource for quantum computing. Researchers from the Quantum Optomechanics group at the Niels Bohr Institute, University of Copenhagen, recently entangled two laser beams through bouncing them off the same mechanical resonator, a tensioned membrane. This provides a novel way of entangling disparate electromagnetic fields, from microwave radiation to optical beams. In particular, creating entanglement between optical and microwave fields would be a key step towards solving the long-standing challenge of sharing entanglement between two distant quantum computers operating in the microwave regime. The result is now published in Nature Communications.

In a future quantum internet, that is the internet of quantum computers, entanglement needs to be shared between two distant quantum computers. This is typically done with electromagnetic links like optical fibers. Presently, one of the most advanced quantum systems is based on superconducting circuits, which work in the microwave regime. As advanced as it is, connecting such computers in networks still poses a steep challenge: microwaves can’t propagate far without loss which is harmful to quantum computing tasks. One way of alleviating this problem is to first entangle microwaves with optical fields, then use optical links, with far lower loss, for long-distance communication. However, due to large difference in wavelengths (millimeters for microwaves and micrometers for light), this conversion remains a challenge…