Physicists at the National Institute of Standards and Technology (NIST) have used charged atoms (ions) to demonstrate a quantum physics version of computer memory lasting longer than 10 seconds—more than 100,000 times longer than in previous experiments on the same ions. The advance improves prospects for making practical, reliable quantum computers (which make use of the properties of quantum systems rather than transistors for performing calculations or storing information). Quantum computers, if they can be built, could break today’s best encryption systems, accelerate database searching, develop novel products such as fraud-proof digital signatures or simulate complex biological systems to help design new drugs.
Quantum memory must be able to store “superpositions,” an unusual property of quantum physics in which a quantum bit (qubit) such as an ion represents both 0 and 1 at the same time. The new approach enables qubits to maintain superpositions over 1 million times longer than might be needed to carry out the information processing steps in a future quantum computer. The advance is, therefore, an important step toward the goal of designing a “fault tolerant” quantum computer because it significantly reduces the computing resources needed to correct memory errors.
In related experiments also described in the paper, NIST scientists demonstrated that pairs of “entangled” ions can retain their quantum states for up to about 7 seconds. Entanglement is another unusual property of quantum physics that correlates the behavior of physically separated ions. Superposition and entanglement are the two key properties expected to give quantum computers great power.
Observing Quantum Transactions In A Nanotube Excitons are "quasiparticles" created when a photon strikes a semiconductor and excites an electron to a higher energy level. The electron leaves behind a positively charged void called a "hole." That hole pairs with the electron to form the exciton, which takes on a life of its own that ends abruptly when it emits a photon or becomes quenched.
Quantum Bit (qubit) Circuit NEC Corporation, Japan Science and Technology Agency (JST) and the Institute of Physical and Chemical Research (RIKEN) have together successfully demonstrated the world's first quantum bit (qubit) circuit that can control the strength of coupling between qubits. Technology achieving control of the coupling strength between qubits is vital to the realization of a practical quantum computer, and has been long awaited in the scientific field.
Spintronics Technology In 1994, Bandyopadhyay and colleagues were the first group to propose the use of spin in classical computing. Then two years later, they were among the first researchers to propose the use of spin in quantum computing. The recent work goes a long way toward implementing some of these ideas.
Center for Extreme Quantum Information Theory (xQIT) The new center enables a major new push by MIT theorists in the international race to determine the ultimate capabilities of quantum information systems. Establishing these theoretical capabilities would be a step towards being able to exploit quantum effects for novel applications, including computers, communication networks and global positioning systems.
Designing Quantum Computers As if building a computer out of rubidium atoms and laser beams weren’t difficult enough, scientists sometimes have to work as if blindfolded: The quirks of quantum physics can cause correlations between the atoms to fade from view at crucial times.
Quantum Computer Demonstrated Quantum computing offers the potential to create value in areas where problems or requirements exceed the capability of digital computing, the company said. But D-Wave explains that its new device is intended as a complement to conventional computers, to augment existing machines and their market, not as a replacement for them.
Quantum Computing Breakthrough "Our work represents a breakthrough in the search for a nanoscopic [atomic scale] mechanism that could be used for a data readout device," says Christoph Boehme, assistant professor of physics at the University of Utah. "We have demonstrated experimentally that the nuclear spin orientation of phosphorus atoms embedded in silicon can be measured by very subtle electric currents passing through the phosphorus atoms."
Research: Ion Trap Physicists at the National Institute of Standards and Technology (NIST) have designed and built a novel electromagnetic trap for ions that could be easily mass produced to potentially make quantum computers large enough for practical use. The new trap, described in the June 30 issue of Physical Review Letters,* may help scientists surmount what is currently the most significant barrier to building a working quantum computer—scaling up components and processes that have been successfully demonstrated individually.
Information Processing In the drive to understand and harness quantum effects as they relate to information processing, scientists in Waterloo and Massachusetts have benchmarked quantum control methods on a 12-Qubit system. Their research was performed on the largest quantum information processor to date.
A Quantum Computer, One Dot at a Time Quantum computers do not yet exist, but it is known that they can bypass all known encryption schemes used today on the Internet. Quantum computers also are capable of efficiently solving the most important equation in quantum physics: the Schrödinger equation, which describes the time-dependence of quantum mechanical systems. Hence, if quantum computers can be built, they likely will have as large an impact on technology as the transistor.