Featured Research

from universities, journals, and other organizations

University Of Maryland Physicists Take Fundamental Step Toward Quantum Computing

Date:
May 19, 2003
Source:
University Of Maryland, College Park
Summary:
University of Maryland physicists have come one step closer to a quantum computer by demonstrating the existence of entangled states between two quantum bits (qubits), each created with a type of solid state circuit known as a Josephson junction. Published in this week's issue of the journal Science, the results represent the latest advance in a broad scientific effort to apply properties of quantum physics to the creation of computers far more powerful than any of today's supercomputers.

COLLEGE PARK, Md. -- University of Maryland physicists have come one step closer to a quantum computer by demonstrating the existence of entangled states between two quantum bits (qubits), each created with a type of solid state circuit known as a Josephson junction. Published in this week's issue of the journal Science, the results represent the latest advance in a broad scientific effort to apply properties of quantum physics to the creation of computers far more powerful than any of today's supercomputers.

A team of physicists led by professor Fred Wellstood of the university's Center for Superconductivity Research (a research center housed within the Department of Physics) says their findings are the first to indicate the successful creation of entanglement between two Josephson-junction qubits. Entanglement is an effect of quantum mechanics that blurs the distinction between individual particles such that it is impossible to describe the particles separately no matter how far apart you physically move them.

"Entanglement is essential to quantum computing because it is the linked quality that builds exponentially more information into quantum bits than is possible with classical computing bits," said Andrew Berkley, the paper's lead author and a graduate student in the Department of Physics. "Our current findings, which build on the work of many others, moves us further along the road toward a quantum computer, and indicate that Josephson junctions could eventually be used to build such a computer."

What is Quantum Computing?

A bit (short for binary digit) is the smallest unit of data in a computer. In computers today, a bit has a single value, either 0 or 1. However, with entanglement, a quantum bit, or qubit, can have not only its individual states (0 or 1), but also the possibility of shared states with every other qubit. Two bits can represent or store only two pieces of information, but two entangled qubits can store four pieces of information at the same time. This quantum advantage increases exponentially as the number of bits increase. Six bits, for example, can represent only 6 pieces of information, while six qubits can represent 64 pieces of information.

Electrons or Electronics

Current efforts to develop quantum computers can be grouped into two categories. The first one consists of researchers working with atomic particles, like atoms or electrons, for which a quantum nature and entangled states are inherent. A major question for these researchers is how to "scale up" from methods for manipulating individual or small numbers of such particles to actually building workable computers.

The second category, which includes Wellstood, Berkley and their colleagues, consists of scientists working with solid-state electronic devices rather than subatomic particles. The leap from such devices to a working computer is potentially much more manageable. Here, the major challenge has been to achieve, at a macroscopic level, the quantum states naturally present at the atomic level. By demonstrating entanglement between two Josephson junctions, the Maryland work has provided important evidence that the necessary quantum behavior is present at the macroscopic level.

The Josephson junction device used by the Maryland team is made up of two superconductors separated by an insulating layer so thin that electrons can cross through it. Quantum mechanics allows electrons to flow through the insulating layer, an effect not allowed by classical physics. Josephson junctions are made by the same techniques used to make conventional integrated circuits, so they are well suited for scaling up to the thousand or so junctions needed to make a working quantum computer.

"Entangled Macroscopic Quantum States in Two Superconducting Qubits," Science, May 15, 2003, A.J. Berkley, H. Xu, R.C. Ramos, M.A. Gubrud, F.W. Strauch, P.R. Johnson, J.R. Anderson, A.J. Dragt, C.J. Lobb, and F.C. Wellstood, Center for Superconductivity Research Department of Physics, University of Maryland.

For More Information:

About the paper, please visit http://www.sciencemag.org/cgi/content/abstract/1084528

About the University of Maryland, please visit http://www.umd.edu About the Center for Superconductivity, please visit http://www.csr.umd.edu


Story Source:

The above story is based on materials provided by University Of Maryland, College Park. Note: Materials may be edited for content and length.


Cite This Page:

University Of Maryland, College Park. "University Of Maryland Physicists Take Fundamental Step Toward Quantum Computing." ScienceDaily. ScienceDaily, 19 May 2003. <www.sciencedaily.com/releases/2003/05/030519083913.htm>.
University Of Maryland, College Park. (2003, May 19). University Of Maryland Physicists Take Fundamental Step Toward Quantum Computing. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2003/05/030519083913.htm
University Of Maryland, College Park. "University Of Maryland Physicists Take Fundamental Step Toward Quantum Computing." ScienceDaily. www.sciencedaily.com/releases/2003/05/030519083913.htm (accessed July 28, 2014).

Share This




More Computers & Math News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Google's Next Frontier: The Human Body

Google's Next Frontier: The Human Body

Newsy (July 27, 2014) — Google is collecting genetic and molecular information to paint a picture of the perfectly healthy human. Video provided by Newsy
Powered by NewsLook.com
Congress OKs Unlocking Phones From Carriers

Congress OKs Unlocking Phones From Carriers

Newsy (July 26, 2014) — A bill legalizing "unlocking," or untethering a phone from its default wireless carrier, has passed Congress and is expected to be signed into law. Video provided by Newsy
Powered by NewsLook.com
Apple Acquires 'Pandora of Books' Service BookLamp

Apple Acquires 'Pandora of Books' Service BookLamp

Newsy (July 26, 2014) — Apple reportedly acquired analytics and recommendation engine BookLamp for between $10 and $15 million. Video provided by Newsy
Powered by NewsLook.com
Wikipedia Puts Congress in Time Out, Blocks Editing

Wikipedia Puts Congress in Time Out, Blocks Editing

Newsy (July 26, 2014) — An IP address within the House of Representatives was banned from editing Wikipedia articles for 10 days after it made some questionable changes. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins