New light storage for quantum computers

Researchers slow down single photons to four percent of the speed of light

Atoms slow down photons © IFW Dresden
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In experiments at the interface of semiconductor and atomic physics, an international team of scientists has succeeded in slowing down individual photons to four percent of the speed of light. This is an important result, which may mean the breakthrough in the development of quantum storage for optical data pulses, for example in quantum computers, the researchers report in the journal Nature Photonics.

Semiconductor quantum dots consist of several tens of thousands of atoms, forming "islands" of only a few nanometers - equivalent to millionths of a millimeter. Due to these small dimensions, charge carriers can no longer move freely here. The energy states are quantized like in an atom, so that quantum dots are also called artificial atoms.

An important property of semiconductor quantum dots is the ability to emit single photons. As semiconductors, they are also easy to integrate into common microelectronic systems.

New type of quantum dots developed

Scientists at the Leibniz Institute for Solid State and Materials Research Dresden and the Technical University (TU) Delft have now developed a new type of quantum dot that emits photons at exactly the frequency that is appropriate for the light barrier used.

In their experiments, the researchers conducted single photons emitted by the quantum dots through a gas of rubidium atoms. As a result, the individual photons are decelerated to such an extent that they are trapped in the rubidium gas in a controlled manner for a short time without changing themselves. display

Quantum memory for visually transmitted information in sight

According to the researchers, these results may form the basis for the development of a quantum memory for optically transmitted information. It is the world's first demonstration of non-classical light storage based on single, on-demand photons, scientists report in Nature Photonics. (Nature Photonics, 2011; doi: 10.1038 / nphoton.2011.16)

(Leibniz Institute for Solid State and Materials Research Dresden, 29.03.2011 - DLO)