Quantum electronics: Two photons and chips

Jan 20, 2006

Scientists at Toshiba Research Europe Limited (Cambridge, UK) believe they are on to a way of producing entangled twins of photons using a simple semiconductor electronic device. Such a chip-based source of entangled photons - light particles - would be a tremendous boon to quantum information technology.

Pairs of photons with properties that are mutually interdependent, owing to a quantum-mechanical effect called entanglement, are the basic currency of quantum-based information processing.

Entangled pairs can be used, for example, to implement quantum cryptography, an ultra-secure way of transmitting information, and quantum computing, which in principle offers much more computer power than today's conventional devices. But making entangled photons on demand is not easy.

Andrew Shields and colleagues report in last week’s Nature [Nature, 12 January, pp179-182] what appear to be entangled photons being emitted from tiny blobs, called quantum dots, of the semiconductor indium arsenide, a material commonly used in solid-state light-emitting devices.

The quantum dots emit pairs of photons when their electrons are boosted to a higher energy by laser light and then release this extra energy as light. By using a magnetic field to tweak the conditions under which the photons are emitted, the researchers were able to generate pairs that appear to be entangled in their polarization states — that is, the plane of polarization of one of the pair depends on that of the other, so that a measurement made on one of them determines the polarization of the other.

If this process can be more precisely controlled, a simple semiconductor light-emitting diode might be used as a compact, robust and reliable source of entangled pairs.

Source: Nature

Explore further: 'Squid skin' metamaterials project yields vivid color display

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

And so they beat on, flagella against the cantilever

10 hours ago

A team of researchers at Boston University and Stanford University School of Medicine has developed a new model to study the motion patterns of bacteria in real time and to determine how these motions relate ...

Tandem microwave destroys hazmat, disinfects

14 hours ago

Dangerous materials can be destroyed, bacteria spores can be disinfected, and information can be collected that reveals the country of origin of radiological isotopes - all of this due to a commercial microwave ...

Physicists design zero-friction quantum engine

14 hours ago

(Phys.org) —In real physical processes, some energy is always lost any time work is produced. The lost energy almost always occurs due to friction, especially in processes that involve mechanical motion. ...

Cornell theorists continue the search for supersymmetry

16 hours ago

(Phys.org) —It was a breakthrough with profound implications for the world as we know it: the Higgs boson, the elementary particle that gives all other particles their mass, discovered at the Large Hadron ...

User comments : 0