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First Electronic Quantum Processor Created
ScienceDaily is reporting that the first rudimentary solid-state quantum processor has been created by a team led by Yale University researchers. "Working with a group of theoretical physicists led by Steven Girvin, the Eugene Higgins Professor of Physics & Applied Physics, the team manufactured two artificial atoms, or qubits ('quantum bits'). While each qubit is actually made up of a billion aluminum atoms, it acts like a single atom that can occupy two different energy states. These states are akin to the '1' and '0' or 'on' and 'off' states of regular bits employed by conventional computers. Because of the counterintuitive laws of quantum mechanics, however, scientists can effectively place qubits in a 'superposition' of multiple states at the same time, allowing for greater information storage and processing power."
You can find the lab site here with several papers freely available in pre-publication form on arxiv from the researchers. I'm trying to find the "basic algorithms" the article alludes to that these rudimentary processors can perform. I thought only a handful were applicable (Shor's algorithm) to quantum computing. Anyone know?
My work here is dung.
they did not manufacture "two artificial atoms, or qubits". They manufactured two clusters of atoms that acted as qubits.
A qubit is not actually a quantum particle. It is a unit of quantum information. Now, do you consider the qubit to be the system or the state?
The ScienceDaily article and the /. summary seem to be confused on the experimental setup. From the Nature article, "[e]ach qubit has a split Josephson junction...." The Josephson effect is an effect where two superconductors are separated by a very thin insulating layer. A "supercurrent" composed of paired correlated electrons (Cooper pairs) can tunnel across this barrier under certain circumstances. Cooper pairs act as bosons, just as atoms do in Bose-Einstein condensates, so they have long been a focus of research for quantum computing. In this experiment, the device was a "180nm Nb film was d.c.-magnetron sputtered on the epipolished surface of an R-plane corundum wafer," meaning that the superconductor they used was niobium, and the insulator was aluminum oxide, aka corundum. They built it out of these, in other words.
They go on to mention that the apparatus was cooled to 13 millikelvin using a helium dilution refrigerator. Now, niobium is superconductive to about 9 kelvin in the pure state (and about 23 kelvin in some alloys), so I would assume the extra effort to make it that cold has more to do with preserving the delicate electronic state of the qubits than with merely chilling the superconductors.
"FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."