Significant Advance in Quantum Computing Achieved
Two superconducting devices have been coaxed into a special, interdependent state that mimics the unusual interactions sometimes seen in pairs of atoms, according to a team of physicists at the National Institute of Standards and Technology (NIST) and University of California, Santa Barbara (UCSB). The experiments, performed at the NIST laboratory in Boulder, Colo., are an important step toward the possible use of “artificial atoms” made with superconducting materials for storing and processing data in an ultra-powerful quantum computer of the future.
Source: NISTThe work, reported in the Feb. 25 issue of the journal Science*, demonstrates that it is possible to measure the quantum properties of two interconnected artificial atoms at virtually the same time. Until now, superconducting qubits—quantum counterparts of the 1s and 0s used in today’s computers—have been measured one at a time to avoid unwanted effects on neighboring qubits. The advance shows that the properties of artificial atoms can be coordinated in a way that is consistent with a quantum phenomenon called “entanglement” observed in real atoms. Entanglement is the “quantum magic” allowing the construction of logic gates in a quantum computer, a means of ensuring that the value of one qubit can be determined by the value of another in a predictable way.
“This opens the door to performing simple logic operations using artificial atoms, an important step toward possibly building superconducting quantum computers,” says John Martinis, who began the superconducting quantum computing effort at NIST and is now on the physics faculty at UCSB.
“Whether or not quantum computing becomes practical, this work is producing new ways to design, control and measure the quantum world of electrical systems,” says Ray Simmonds, a NIST physicist and a co-author of the Science paper. “We have already detected previously unknown, individual nanoscale quantum systems that have never before been directly observed, a discovery that may lead to unanticipated advances in nanotechnology.”
Optical micrograph showing an "artificial atom" made with a superconducting circuit. The red arrow points to the heart of the qubit -- the Josephson junction device that might be used in a future quantum computer to represent a 1, 0, or both values at once.
If they can be built, quantum computers—relying on the rules of quantum mechanics, nature’s instruction book for the smallest particles of matter—someday might be used for applications such as fast and efficient code breaking, optimizing complex systems such as airline schedules, much faster database searching and solving of complex mathematical problems, and even the development of novel products such as fraud-proof digital signatures.
0