Researchers have successfully tested the strong coupling between light and matter read more at here www.spinonews.com/index.php/item/1249-researchers-have-successfully-tested-the-strong-coupling-between-light-and-matter

University of Waterloo's Institute for Quantum Computing (IQC) researchers recorded an interaction between light and matter 10 times larger than previously seen. The strength of the interaction between photons and a qubit was so large that it opens the door to a realm of physics and applications unattainable until now.

Pol Forn-Diaz, a postdoctoral fellow at IQC, said, the possibilities are exciting because our circuit could potentially act as a quantum simulator to study other interesting quantum systems in nature.

The ultra-strong coupling between photons and qubits may lead to the exploration of new physics related to biological processes, exotic materials, and even relativistic physics.

To conduct their experiment, the researchers fabricated aluminum circuits and then cooled them in dilution refrigerators to a temperature as low as one percent of a degree above absolute zero.

At these temperatures the circuits can become superconducting, meaning that they can carry a current without resistance or losing energy. These aluminum circuits, known as superconducting qubits, and they can behave as artificial atoms.

To control the quantum state of a superconducting circuit, the researchers sent photons using microwave pulses into the superconducting circuit and applied a small magnetic field through a coil inside the dilution refrigerator.

By measuring the photon transmission, the researchers could define the resonance of the qubit, indicated by the reflection of the photons of the qubit. Usually, the qubit resonance is centered around a very narrow range of frequencies.

After measuring a range of frequency, researchers identified a strong interaction between qubit and photons. It is so strong that the qubit sees most of the photons that propagate in the circuit, which is a distinctive signature of ultra-strong coupling in an open system.