Featured Research

from universities, journals, and other organizations

Quantum Mechanics Advance Reported Using Superconducting Electrical Circuit

Date:
September 24, 2009
Source:
University of California - Santa Barbara
Summary:
Physicists have made an important advance in quantum mechanics, demonstrating that they could detect the quantum correlations in the results of measurements of entangled quantum bits, using a superconducting electrical circuit.

Physicists at UC Santa Barbara have made an important advance in quantum mechanics using a superconducting electrical circuit. The finding is reported in this week's issue of the journal Nature.

The researchers showed that they could detect the quantum correlations in the results of measurements of entangled quantum bits, using a superconducting electrical circuit. The correlations are stronger than can be obtained using classical (non-quantum mechanical) physics, and according to the physicists, this illustrates that the oddities of quantum mechanics clearly extend to macroscopic systems. The work is part of an ongoing collaboration between the UCSB laboratories of John Martinis and Andrew Cleland.

The results of measurements in quantum mechanics are intrinsically unpredictable, according to the theory of quantum mechanics, and yet still contain very strong correlations, in contradiction with classical physics. In particular, measurements of "entangled states," such as a pair of particles with opposite spins, allow stringent tests of the predicted discrepancy between quantum and classical physics, as described by the "Bell inequalities." Measuring such a discrepancy is known as a "Bell violation."

According to quantum theory, Bell violations should be detectable using "qubits," superconducting quantum bits, but measuring these violations is technologically challenging. Martinis, Cleland, and their colleagues have overcome these challenges, and report a clear violation of Bell's inequality with two entangled superconducting qubits. Thus, they have demonstrated that this macroscopic electrical circuit is a quantum system.

The measurement of a Bell violation in a superconducting circuit was recently stated to be the next primary challenge for the superconducting qubit community, according to Martinis.

Martinis said: "This experiment has met this challenge, achieved by performing a very demanding measurement on a pair of Josephson qubits, a measurement that requires excellent control over qubit state preparation, qubit entanglement, and very high fidelity single-shot state measurements of the entangled qubits. It directly proves that quantum mechanics is the only possible description for the behavior of a macroscopic electrical circuit."

Additional co-authors on the paper (all at UCSB at the time of the research) are: Markus Ansmann, Haohua Wang, Radoslaw C. Biaalczak, Max Hofheinz, Erik Lucero, Matthew Neeley, Aaron D. O'Connell, Daniel Sank, Martin Weides, and James Wenner.


Story Source:

The above story is based on materials provided by University of California - Santa Barbara. Note: Materials may be edited for content and length.


Journal Reference:

  1. Markus Ansmann, H. Wang, Radoslaw C. Bialczak, Max Hofheinz, Erik Lucero, M. Neeley, A. D. O'Connell, D. Sank, M. Weides, J. Wenner, A. N. Cleland & John M. Martinis. Violation of Bell's inequality in Josephson phase qubits. Nature, 2009; DOI: 10.1038/nature08363

Cite This Page:

University of California - Santa Barbara. "Quantum Mechanics Advance Reported Using Superconducting Electrical Circuit." ScienceDaily. ScienceDaily, 24 September 2009. <www.sciencedaily.com/releases/2009/09/090923151730.htm>.
University of California - Santa Barbara. (2009, September 24). Quantum Mechanics Advance Reported Using Superconducting Electrical Circuit. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2009/09/090923151730.htm
University of California - Santa Barbara. "Quantum Mechanics Advance Reported Using Superconducting Electrical Circuit." ScienceDaily. www.sciencedaily.com/releases/2009/09/090923151730.htm (accessed July 25, 2014).

Share This




More Computers & Math News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Mobile App Gives Tour of Battle of Atlanta Sites

Mobile App Gives Tour of Battle of Atlanta Sites

AP (July 25, 2014) — Emory University's Center for Digital Scholarship has launched a self-guided mobile tour app to coincide with the 150th anniversary of the Civil War's Battle of Atlanta. (July 25) Video provided by AP
Powered by NewsLook.com
Bill Gates: Health, Agriculture Key to Africa's Development

Bill Gates: Health, Agriculture Key to Africa's Development

AFP (July 24, 2014) — Health and agriculture development are key if African countries are to overcome poverty and grow, US software billionaire Bill Gates said Thursday, as he received an honourary degree in Ethiopia. Duration: 00:36 Video provided by AFP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) — Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) — 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
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