New research into light particles challenges understanding of quantum theory

March 29, 2017

Scientists have discovered a new mechanism involved in the creation of paired light particles, which could have significant impact on the study of quantum physics.

Researchers at the University of East Anglia (UEA) have shown that when photons - the fundamental particles of light - are created in pairs, they can emerge from different, rather than the same, location.

The ground-breaking research could have significant implications for quantum physics, the theoretical basis of modern physics. Until now, the general assumption was that such photon pairs necessarily originate from single points in space.

Quantum entanglement - when particles are linked so closely that what affects one directly affects the other - is widely used in labs in numerous processes from quantum cryptography to quantum teleportation.

The UEA team were studying a process called spontaneous parametric down-conversion (SPDC), in which photon beams are passed through a crystal to generate entangled pairs of photons.

Prof David Andrews in UEA's School of Chemistry said: "When the emergent pairs equally share the energy of the input, this is known as degenerate down-conversion, or DDC.

"Until now, it has been assumed that such paired photons come from the same location. Now, the identification of a new delocalized mechanism shows that each photon pair can be emitted from spatially separated points, introducing a new positional uncertainty of a fundamental quantum origin."

The entanglement of the quantum states in each pair has important applications in quantum computing - theoretical computation systems that could potentially process big data problems at incredible speeds - as well as other areas of quantum physics.

The findings are also significant because they place limits on spatial resolution. Prof Andrews said: "Everything has a certain quantum 'fuzziness' to it, and photons are not the hard little bullets of light that are popularly imagined."

The study 'Nonlocalized generation of correlated photon pairs in degenerate down-conversion' by Kayn A. Forbes, Jack S. Ford, and David L. Andrews is published in the journal Physical Review Letters.

University of East Anglia

Related Quantum Computing Articles from Brightsurf:

Bringing a power tool from math into quantum computing
The Fourier transform is a mathematical operation essential to virtually all fields of physics and engineering.

New detector breakthrough pushes boundaries of quantum computing
A new paper published in Nature shows potential for graphene bolometers to become a game-changer for quantum technology

A molecular approach to quantum computing
Molecules in quantum superposition could help in the development of quantum computers.

Cosmic rays may soon stymie quantum computing
Infinitesimally low levels of radiation, such as from incoming cosmic rays, may soon stymie progress in quantum computing.

UVA pioneers study of genetic diseases with quantum computing
Scientists are harnessing the mind-bending potential of quantum computers to help us understand genetic diseases - even before quantum computers are a thing.

New method predicts spin dynamics of materials for quantum computing
Researchers at UC Santa Cruz have developed a theoretical foundation and new computational tools for predicting a material's spin dynamics, a key property for building solid-state quantum computing platforms and other applications of spintronics.

Speeding-up quantum computing using giant atomic ions
An international team of researchers have found a new way to speed up quantum computing that could pave the way for huge leaps forward in computer processing power.

Boson particles discovery provides insights for quantum computing
Researchers working on a U.S. Army project discovered a key insight for the development of quantum devices and quantum computers.

In leap for quantum computing, silicon quantum bits establish a long-distance relationship
In an important step forward in the quest to build a quantum computer using silicon-based hardware, researchers at Princeton have succeeded in making possible the exchange of information between two qubits located relatively far apart -- about the length of a grain of rice, which is a considerable distance on a computer chip.

Diversity may be key to reducing errors in quantum computing
In quantum computing, as in team building, a little diversity can help get the job done better, computer scientists have discovered.

Read More: Quantum Computing News and Quantum Computing Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to