Featured Research

from universities, journals, and other organizations

Michigan Researchers Achieve Quantum Entanglement Of Three Electrons

Date:
February 27, 2003
Source:
University Of Michigan
Summary:
The quantum entanglement of three electrons, using an ultrafast optical pulse and a quantum well of a magnetic semiconductor material, has been demonstrated in a laboratory at the University of Michigan, marking another step toward the realization of a practical quantum computer.

ANN ARBOR, Mich.--- The quantum entanglement of three electrons, using an ultrafast optical pulse and a quantum well of a magnetic semiconductor material, has been demonstrated in a laboratory at the University of Michigan, marking another step toward the realization of a practical quantum computer. While several experiments in recent years have succeeded in entangling pairs of particles, few researchers have managed to correlate three or more particles in a predictable fashion.

The results were presented in an article on Nature Materials' web site on February 23 and will appear in the March 4 issue of Nature Materials, titled "Optically induced multispin entanglement in a semiconductor quantum well." Authors of the paper are Jiming Bao, Andrea V. Bragas, Jacek K. Furdyna (University of Notre Dame), and Roberto Merlin.

Entanglement, which is essential to the creation of a quantum computer, is one of the mysterious properties of quantum mechanics that contradicts the notions of classical realism. Quantum computers will be able to perform highly complex tasks that would be impossible for a classical computer, at great speed.

Briefly, entanglement describes a particular state of a set of particles of energy or matter for which correlations exist, so that the particles affect each other regardless of how far apart they are. Einstein called it "spooky action at a distance." We know that we must be able to harness entanglement in order to develop the quantum gates necessary for storing and processing information in practical quantum computers. These devices will offer enormously enhanced computing power that would permit extremely fast ways to solve certain mathematical problems, such as the factorization of large numbers.

The Michigan team, which has been working on the problem for several years, used ultrafast (50-100 femtosecond) laser pulses and coherent techniques to create and control spin-entangled states in a set of non-interacting electrons bound to donors in a CdTe quantum well. The method, which relies on the exchange interaction between localized excitons and paramagnetic impurities, could in principle be used to entangle an arbitrarily large number of spins.

In the presence of an external magnetic field, a resonant laser pulse creates localized excitons (bound electron-hole pairs) of radius ~ 0.005 microns in the CdTe well. Electrons bound to donor impurities within that radius feel the presence of the exciton in such a way that they became entangled after the exciton is gone. The process involves resonant Raman transitions between Zeeman split spin states. In the experiments, the signature of entanglement involving m electrons is the detection of the mth-harmonic of the fundamental Zeeman frequency in the differential reflectivity data.

"The community is trying various approaches to achieve controllable interactions between qubits. We've seen a variety of proposed solutions from atomic physicists involving trapped ions and atoms and even 'flying qubits' based on light," said Merlin. "Solutions based on semiconductor technology, like ours for example, may well hold more promise for practical implementation when combined with advances in nanotechnology."

The experiments have so far involved a large ensemble of sets of 3 electrons. "Our procedure is potentially set-specific and scalable, which means that it shows definite promise for quantum computing applications," Merlin said. Cryptography is expected to be one of the first such applications.

The research was conducted at OPIL (Optical Physics Interdisciplinary Laboratory), a laboratory of the FOCUS (Frontiers in Optical Coherent and Ultrafast Science) Center of the University of Michigan and funded by ACS Petroleum Research Fund, NSF (National Science Foundation) and the AFOSR (Air Force Office of Scientific Research) through the MURI (Multidisciplinary University Research Initiative) program.

To read the entire paper, go to http://dx.doi.org/10.1038/Nmat839 . For more information about the University of Michigan's FOCUS Center, see http://www.umich.edu/~focuspfc/main.html .


Story Source:

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


Cite This Page:

University Of Michigan. "Michigan Researchers Achieve Quantum Entanglement Of Three Electrons." ScienceDaily. ScienceDaily, 27 February 2003. <www.sciencedaily.com/releases/2003/02/030227071834.htm>.
University Of Michigan. (2003, February 27). Michigan Researchers Achieve Quantum Entanglement Of Three Electrons. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2003/02/030227071834.htm
University Of Michigan. "Michigan Researchers Achieve Quantum Entanglement Of Three Electrons." ScienceDaily. www.sciencedaily.com/releases/2003/02/030227071834.htm (accessed September 16, 2014).

Share This



More Matter & Energy News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Space Race Pits Bezos Vs Musk

Space Race Pits Bezos Vs Musk

Reuters - Business Video Online (Sep. 16, 2014) Amazon CEO Jeff Bezos' startup will team up with Boeing and Lockheed to develop rocket engines as Elon Musk races to have his rockets certified. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
MIT's Robot Cheetah Unleashed — Can Now Run, Jump Freely

MIT's Robot Cheetah Unleashed — Can Now Run, Jump Freely

Newsy (Sep. 16, 2014) MIT developed a robot modeled after a cheetah. It can run up to speeds of 10 mph, though researchers estimate it will eventually reach 30 mph. Video provided by Newsy
Powered by NewsLook.com
Manufacturer Prints 3-D Car In Record Time

Manufacturer Prints 3-D Car In Record Time

Newsy (Sep. 15, 2014) Automobile manufacturer Local Motors created a drivable electric car using a 3-D printer. Printing the body only took 44 hours. Video provided by Newsy
Powered by NewsLook.com
Refurbished New York Subway Tunnel Unveiled After Sandy Damage

Refurbished New York Subway Tunnel Unveiled After Sandy Damage

Reuters - US Online Video (Sep. 15, 2014) New York officials unveil subway tunnels that were refurbished after Superstorm Sandy. Nathan Frandino reports. Video provided by Reuters
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