Subscribe free to our newsletters via your
. Space Industry and Business News .




CHIP TECH
Breakthrough offers new route to large-scale quantum computing
by Staff Writers
Princeton NJ (SPX) Oct 22, 2012


A circuit uses microwaves to read the quantum state of an electron, a potentially scalable route to developing a quantum computer. Credit: Jason Petta/Princeton University.

In a key step toward creating a working quantum computer, Princeton researchers have developed a method that may allow the quick and reliable transfer of quantum information throughout a computing device

The finding, by a team led by Princeton physicist Jason Petta, could eventually allow engineers to build quantum computers consisting of millions of quantum bits, or qubits. So far, quantum researchers have only been able to manipulate small numbers of qubits, not enough for a practical machine.

"The whole game at this point in quantum computing is trying to build a larger system," said Andrew Houck, an assistant professor of electrical engineering who is part of the research team.

To make the transfer, Petta's team used a stream of microwave photons to analyze a pair of electrons trapped in a tiny cage called a quantum dot. The "spin state" of the electrons - information about how they are spinning - serves as the qubit, a basic unit of information. The microwave stream allows the scientists to read that information.

"We create a cavity with mirrors on both ends - but they don't reflect visible light, they reflect microwave radiation," Petta said. "Then we send microwaves in one end, and we look at the microwaves as they come out the other end. The microwaves are affected by the spin states of the electrons in the cavity, and we can read that change."

In an ordinary sense, the distances involved are very small; the entire apparatus operates over a little more than a centimeter. But on the subatomic scale, they are vast. It is like coordinating the motion of a top spinning on the moon with another on the surface of the earth.

"It's the most amazing thing," said Jake Taylor, a physicist at the National Institute of Standards and Technology and the Joint Quantum Institute at the University of Maryland, who worked on the project with the Princeton team. "You have a single electron almost completely changing the properties of an inch-long electrical system."

For years, teams of scientists have pursued the idea of using quantum mechanics to build a new machine that would revolutionize computing. The goal is not build a faster or more powerful computer, but to build one that approaches problems in a completely different fashion.

Standard computers store information as classical "bits", which can take on a value of either 0 or 1. These bits allow programmers to create the complex instructions that are the basis for modern computing power. Since Alan Turing took the first steps toward creating a computer at Princeton in 1936, engineers have created vastly more powerful and complex machines, but this basic binary system has remained unchanged.

The power of a quantum computer comes from the strange rules of quantum mechanics, which describe the universe of subatomic particles. Quantum mechanics says that an electron can spin in one direction, representing a 1, or in another direction, a 0. But it can also be in something called "superposition" representing all states between 1 and 0. If scientists and engineers can build a working machine that takes advantage of this, they would open up entirely new fields of computing.

"The point of a quantum computer is not that they can do what a normal computer can do but faster; that's not what they are," said Houck. "The quantum computer would allow us to approach problems differently. It would allow us to solve problems that cannot be solved with a normal computer."

Mathematicians are still working on possible uses for a quantum system, but the machines could allow them to accomplish tasks such as factoring currently unfactorable numbers, breaking codes or predicting the behavior of molecules.

One challenge facing scientists is that the spins of electrons, or any other quantum particles, are incredibly delicate. Any outside influences, whether a wisp of magnetism or glimpse of light, destabilizes the electrons' spins and introduces errors.

Over the years, scientists have developed techniques to observe spin states without disturbing them. (This year's Nobel Prize in physics honored two scientists who first demonstrated the direct observation of quantum particles.) But analyzing small numbers of spins is not enough; millions will be required to make a real quantum processor.

To approach the problem, Petta's team combined techniques from two branches of science: from materials science, they used a structure called a quantum dot to hold and analyze electrons' spins; and from optics, they adopted a microwave channel to transfer the spin information from the dot.

To make the quantum dots, the team isolated a pair of electrons on a small section of material called a "semiconductor nanowire." Basically, that means a wire that is so thin that it can hold electrons like soda bubbles in a straw. They then created small "cages" along the wire. The cages are set up so that electrons will settle into a particular cage depending on their energy level.

This is how the team reads the spin state: electrons of similar spin will repel, while those of different spins will attract. So the team manipulates the electrons to a certain energy level and then reads their position. If they are in the same cage, they are spinning differently; if they are in different cages, the spins are the same.

The second step is to place this quantum dot inside the microwave channel. This allows the team to transfer the information about the pair's spin state - the qubit.

Petta said the next step is to increase the reliability of the setup for a single electron pair. After that, the team plans to add more quantum dots to create more qubits. Team members are cautiously optimistic. There appear to be no insurmountable problems at this point but, as with any system, increasing complexity could lead to unforeseen difficulties.

"The methods we are using here are scalable, and we would like to use them in a larger system," Petta said. "But to make use of the scaling, it needs to work a little better. The first step is to make better mirrors for the microwave cavity."

.


Related Links
Princeton University, Engineering School
Computer Chip Architecture, Technology and Manufacture
Nano Technology News From SpaceMart.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle








CHIP TECH
Optical vortices on a chip
Bristol UK (SPX) Oct 19, 2012
An international research group led by scientists from the University of Bristol and the Universities of Glasgow (UK) and Sun Yat-sen and Fudan in China, have demonstrated integrated arrays of emitters of so call 'optical vortex beams' onto a silicon chip. The work is featured on the cover of the latest issue of Science magazine, published tomorrow [19 October 2012]. Contradicting traditio ... read more


CHIP TECH
Apple opens biggest Asian store in Beijing

Will Apple go for 'kill' with iPad Mini?

Taiwan temple to launch 'divine advice' app

Kennedy Supporting Effort to Develop Satellite Servicing Capabilities

CHIP TECH
$15M order for Harris tactical radios

SPAWAR Atlantic taps Engility

Northrop Grumman Begins Production of EHF SatCom System for B-2 Bomb

Mutualink Selects Benchmark to Manufacture Interoperable Communications Systems on Global Scale

CHIP TECH
AFSPC commander convenes AIB

Proton Lofts Intelsat 23 For Americas, Europe and Africa Markets

India to launch 58 space missions in next 5 years

SpaceX Dragon Successfully Attaches To Space Station

CHIP TECH
NASA's WISE Colors in Unknowns on Jupiter Asteroids

Indra Technology Supports Management And Control Of New Galileo Satellites

Testing of Galileo satellite navigation system can begin

Two more satellites for the Galileo system

CHIP TECH
Boeing EMARSS Risk Reduction Prototype Makes First Flight

NASA Seeks Student Experiments For 2013 High-Altitude Scientific Balloon Flight

Raytheon-led team graduates first Afghan Air Force pilots on Warfighter FOCUS program contract

Second UK F-35 And Marine Corps F-35B Delivered To Eglin

CHIP TECH
Breakthrough offers new route to large-scale quantum computing

Bus service for qubits

Developing the next generation of microsensors

ORNL study confirms magnetic properties of silicon nano-ribbons

CHIP TECH
Landsat Science Team to Help Guide Next Landsat Mission

TerraSAR-X images Bonneville salt flats

Earth Observation Commercial Data Market Remains Strong Despite Slowdown in 2011

Antarctic Rift Subject of International Attention

CHIP TECH
New methods might drastically reduce the costs of investigating polluted sites

Pollution row strangles Italian steel giant ILVA

S. Korean villagers evacuate after toxic leak

Council of war gathers for world's biodiversity crisis




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement