- Quantum interference fine-tuned by Berry phase
BRISTOL, UK – A three-decades-old formula for phase shifting has been used to accurately control quantum interference between atoms, paving the way for fault-tolerant circuits in photonic quantum simulators.
Photonic quantum simulators, systems of photons designed to simulate other quantum systems, are set to be physically realized much sooner than universal quantum computers.
The geometric phase effect, known as Berry phase, was first described by professor Sir Michael Berry of the University of Bristol in 1984. He described the phenomenon as a quantum particle that returns to its start point after a cyclic journey and is found to be subtly changed, or phase-shifted. Berry’s way of phase shifting is reliable for robust methods needed to implement the circuits of a universal quantum computer.
In 1987, Hong Ou and Mandel (HOM) demonstrated how two photons interfere in a very peculiar way, preferring to stick together. The HOM quantum interference effect is at the core of anticipated photonic quantum simulators that, by their very nature, are impossible to run on a conventional computer.
Now, scientists at the university’s Centre for Quantum Photonics have brought these two phenomena together to show how HOM interference can be exquisitely controlled with Berry phase.
The study appeared in Physical Review Letters (doi: 10.1103/PhysRevLett.108.260505).
- phase shifting
- A technique used to generate a phase shift between reference and sample light beams. The phase shift can be performed through the use of a mirror that is moved along the optic axis by a piezoelectric transducer.
- The technology of generating and harnessing light and other forms of radiant energy whose quantum unit is the photon. The science includes light emission, transmission, deflection, amplification and detection by optical components and instruments, lasers and other light sources, fiber optics, electro-optical instrumentation, related hardware and electronics, and sophisticated systems. The range of applications of photonics extends from energy generation to detection to communications and...
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