quantum computers tagged posts

JILA physicists used a strontium lattice atomic clock to simulate magnetic properties long sought in solid materials. The atoms are confined in an optical lattice, shown as an array of disk-shaped traps set at shallow depths. A laser (yellow wave) probes the atoms to couple the atoms’ spins and motions. The two atomic spin states are illustrated in red and blue. Credit: Steven Burrows and Ye Group/JILA

JILA physicists have caused atoms in a gas to behave as if they possess unusual magnetic properties long sought in harder-to-study solid materials. Representing a novel “off-label” use for atomic clocks, the research could lead to the creation of new materials for applications such as “spintronic” devices and quantum computers...

Artist”s impression of a single-atom electron spin, hosted in a silicon crystal and dressed by an oscillating electromagnetic field. Credit: Arne Laucht/UNSW

Australian engineers have created a new quantum bit which remains in a stable superposition for 10 times longer than previously achieved, dramatically expanding the time during which calculations could be performed in a future silicon quantum computer. The new quantum bit, made up of the spin of a single atom in silicon and merged with an electromagnetic field – known as ‘dressed qubit’ – retains quantum information for much longer that an ‘undressed’ atom, opening up new avenues to build and operate the superpowerful quantum computers of the future.

Andrea Morello,CQC2T, UNSW said:”Our decade-long research program had already establi...

43Ca+ qubit states and Raman transitions used for sideband cooling, single-qubit and two-qubit gates. Credit: arxiv.org/abs/1512.04600

The team achieved the logic gate, which places 2 atoms in a state of quantum entanglement and is the fundamental building block of quantum computing, with a precision (or fidelity) substantially greater than the previous world record. Quantum entanglement—a phenomenon described by Einstein as ‘spooky’ but which is at the heart of quantum technologies—occurs when 2 particles stay connected, such that an action on one affects the other, even when they are separated by great distances

The precision of the gate is a measure of how well quantum entanglement works: in our case, 99...

This is Tim Burgess with a silicon wafer on which nanostructures are grown. Credit: Stuart Hay, ANU

This will help in development of low-cost biomedical sensors, quantum computing, and a faster internet. Researcher Tim Burgess added atoms of zinc to lasers 1/100 the diameter of a human hair and made of gallium arsenide – a material used extensively in smartphones and other electronic devices. The impurities led to a 100X improvement in the amount of light from the lasers.

“Normally you wouldn’t even bother looking for light from nanocrystals of gallium arsenide – we were initially adding zinc simply to improve the electrical conductivity,” said Mr Burgess, a PhD student, ANU. “It was only when I happened to check for light emission that I realised we were onto something.”

Gallium arsenide ...