Quantum Memories tagged posts

Two black diamonds on a superconducting chip (12x4mm). The wiggly line is a resonator, coupling the two diamonds.

Atomic defects in diamonds can be used as quantum memories. Researchers at TU Wien have been studying the quantum properties of such diamonds, but only now have they succeeded in coupling the specific defects in two such diamonds with one another. This is an important prerequisite for the development of new applications, such as highly sensitive sensors and switches for quantum computers.

“Unfortunately, quantum states are very fragile and decay very quickly,” explains Johannes Majer, head of the hybrid quantum research group, Institute of Atomic and Subatomic Physics at TU Wien...

An artificial diamond under the optical microscope. The diamond fluoresces because due to a number of nitrogen defects.

How can quantum information be stored as long as possible? An important step forward in the development of quantum memories has been achieved by a research team of TU Wien. Conventional memories used in today’s computers only differentiate between the bit values 0 and 1. In quantum physics, however, arbitrary superpositions of these 2 states are possible. Most of the ideas for new quantum technology devices rely on this “Superposition Principle.” One of the main challenges in using such states is that they are usually short-lived. Only for a short period of time can information be read out of quantum memories reliably, after that it is irrecoverable.

A team at TU Wien has...

Building quantum memories on a chip: Diamond photonic crystal cavities (ladder-like structures) are integrated on a silicon substrate. Green laser light (green arrow) excites electrons on impurity atoms trapped within the cavities, picking up information about their spin states, which can then be read out as red light (red arrow) emitted by photoluminescence from the cavity. The inset shows the nitrogen-vacancy (NV)-nanocavity system, where a nitrogen atom (N) is substituted into the diamond crystal lattice in place of a carbon atom (gray balls) adjacent to a vacancy (V). Layers of diamond and air keep light trapped within these cavities long enough to interact with the nitrogen atom’s spin state and transfer that information via the emitted light. Credit: MIT

The idea of computing systems...