An Otago University physicist is part of an international team of researchers which has developed what they say is the most efficient quantum "memory" for light in the world, and a stepping stone to a future of super-fast computers and ultra-secure communications.
Findings of the Australian National University-led team, of which Otago's Jevon Longdell is a member, were published today in the science journal Nature.
The work not only advanced fundamental research into quantum physics, Dr Longdell said.
"There are applications which could spin out of this work in more everyday life, such as optical detection of ultrasound for health or engineering uses," he said.
Quantum theory says everything can be broken down into tiny packets or 'quanta' of energy, and that light is composed of photons, tiny blobs of quantum energy with a "spin" or natural orientation, similar to a compass needle. The spin can be oriented up or down, representing a one or zero, and flipping from up to down has the same effect as switching a tiny transistor on or off -- the basis of modern computing.
In the world of quantum physics, particles like photons behave in mind-bending fashion, and can actually be oriented up and down simultaneously -- potentially making a quantum-based computer extraordinarily efficient.
Unfortunately, directly observing or measuring the light changes its state and destroys the delicate quantum information.
But the researchers have found a way to store the information about the light particle, manipulate it, and recall it, by trapping the light in a crystal and mapping a three-dimensional record of the particle's quantum state onto special mineral impurities in the crystal.
Measuring this "mapped" information rather than the light avoids destroying it.
Dr Longdell said the memory system had promising applications in developing quantum-based technologies for top-secret communications, with encryptions that are difficult to break and impossible to eavesdrop on without alerting the people sending and receiving information.
Dr Longdell's group at Otago will continue to work with the Australian team to find ways to use the memory in developing practical applications.
