Researchers around the world are racing to develop new quantum-based systems for sensing, communication, computing, and control that have the promise of outperforming traditional systems. Creating stable, measurable, distinguishable quantum states, which would be the heart of any such system, is a daunting task.

Quantum states possess unique properties that can be exploited for developing novel information processing systems. Two key properties, stability and distinguishability, are hard to achieve, however. Extracting information from a quantum system depends on the distinguishability of quantum states, an intrinsic property associated with a property known as orthogonality. Nevertheless, no two Gaussian states (a widely studied class of quantum states) are orthogonal, and this yields an unavoidable error when attempting to distinguish them.

In addition, present quantum devices tend to remain stable only for a fraction of a second, and require complex protocols to distinguish states. Now, researchers at MIT and the University of Ferrara have found a new approach for creating easily distinguishable states that could help to enable the development of these new quantum-based devices.

In a paper published in Science Advances, researchers at the University of Technology Sydney (UTS) in collaboration with the University of Minnesota and Kyung Hee University have found a new way to control quantum light sources, which is one of the key elements needed before quantum technologies can be used reliably in real-world systems.

Lead author Dr. Angus Gale says the research gives scientists a new control mechanism for tiny quantum light sources, bringing them a step closer to being used in practical quantum technologies such as quantum computing, secure communication and ultrasensitive sensing.

“You can measure these quantum emitters and see that they exist, but it’s hard to make them work in practice. This gives us a lever to get closer to that—a step toward the realization of quantum technologies,” said Dr. Gale.