Scientists Create New "Light-trap" Memory Modules

This discovery could be a step forward into constructing what scientists call a quantum computer. Unlike classical computers that use bits to store and process information, the future generation of computers is supposed to use quantum mechanical phenomena, such as superposition and entanglement to process data.

The information is stored in qubits (quantum bits) and the best place to store nebulous stuff called quantum information might be in a small, cold cloud of gas.

The discovery which involves a device called a quantum memory element was made by two separate teams, by placing a cloud of chilled rubidium atoms inside an optical cavity, thus trapping the light between two mirrors.

The principle of trapping light between mirrors is not exactly new, being used to create what we now call a laser (light amplification by stimulated emission of radiation) device, but slightly different. Lasers work by producing a stream of photons inside a tube that has two opposing mirrors, one of them only 99 percent reflective, the laser aperture.

By bouncing the two mirrors, light traveling through the tube excites a gas which will emit ever more photons. When the photons have gathered enough energy they escape through the 99 percent reflective mirror, producing a laser beam.

Quantum computers abandon the classical ordinary bits of information and deal with qubits, a blend of bits that are now used to create uncrackable codes and are supposed to be the solution for ultra fast quantum computers.

Qubits use photons to change energy levels of an atom, to write the information in the same mixture of high and low energy states, but reading such a memory could prove extremely difficult and information easily lost, as the atom could drift away or spontaneously emit the photon containing the data in random directions.

The Bose-Einstein state could solve this paradox, by using not one atom but a bunch of them, acting collectively like a super-atom, which can be easily cooled to very low temperature, to trigger a state of no thermal motion to solve the problem of atoms drifting away.

The cavity was difficult to construct and has been developed from two optical fibers just 0.04 millimeters across, on which mirrors were painted at each end.