Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



Researchers Achieve Quantum Entanglement Of Three Electrons

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.
Ann Arbor - Mar 03, 2003
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.

Related Links
Full Paper Online
University of Michigan's FOCUS Center
SpaceDaily
Search SpaceDaily
Subscribe To SpaceDaily Express

Electronic Circuit Rides A Chemical Film
Chicago - Feb 25, 2003
Chains of molecules known as conducting polymers are versatile materials that can work like electronic circuits. Potential uses include flat panel displays, solar panels, sensing devices and transistors, to name just a few. Their invention won three scientists the Nobel Prize in chemistry.



Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only






Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news 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 All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.