LinuxQuestions.org
Welcome to the most active Linux Forum on the web.
Go Back   LinuxQuestions.org > Forums > Non-*NIX Forums > General
User Name
Password
General This forum is for non-technical general discussion which can include both Linux and non-Linux topics. Have fun!

Notices


Reply
  Search this Thread
Old 01-20-2005, 01:43 AM   #1
jschiwal
LQ Guru
 
Registered: Aug 2001
Location: Fargo, ND
Distribution: SuSE AMD64
Posts: 15,733

Rep: Reputation: 682Reputation: 682Reputation: 682Reputation: 682Reputation: 682Reputation: 682
Will the development of quantum computing lead to faster than light communication?


This is a link to the third page of a Scientific American Article on quantum computing and cryptography.

http://www.sciam.com/article.cfm?cha...mber=3&catID=2

Quote:
Ultimately cryptographers want some form of quantum repeater--in essence, an elementary form of quantum computer that would overcome distance limitations. A repeater would work through what Albert Einstein famously called "spukhafte Fernwirkungen," spooky action at a distance. Anton Zeilinger and his colleagues at the Institute of Experimental Physics in Vienna, Austria, took an early step toward a repeater when they reported in the August 19, 2004, issue of Nature that their group had strung an optical-fiber cable in a sewer tunnel under the Danube River and stationed an "entangled" photon at each end. The measurement of the state of polarization in one photon (horizontal, vertical, and so on) establishes immediately an identical polarization that can be measured in the other.
I think that this is the theoretical principle that prompted Einstein's famous quote 'God doesn't play dice with the Universe.' Allowing for the possibility of faster than light communication between two photon pairs may undermine the theory of relativity.
 
Old 01-20-2005, 03:22 AM   #2
J.W.
LQ Veteran
 
Registered: Mar 2003
Location: Boise, ID
Distribution: Mint
Posts: 6,642

Rep: Reputation: 87
Hard to say. I'm no physicist but in my opinion, any claims to measure the position of a single photon would violate Heisenberg's Uncertainty Principle At least from what I understand. -- J.W.
 
Old 01-20-2005, 03:29 AM   #3
vharishankar
Senior Member
 
Registered: Dec 2003
Distribution: Debian
Posts: 3,178
Blog Entries: 4

Rep: Reputation: 138Reputation: 138
And from wikipedia -- article on the uncertainty principle.

http://en.wikipedia.org/wiki/Uncertainty_principle
 
Old 01-20-2005, 06:43 PM   #4
jschiwal
LQ Guru
 
Registered: Aug 2001
Location: Fargo, ND
Distribution: SuSE AMD64
Posts: 15,733

Original Poster
Rep: Reputation: 682Reputation: 682Reputation: 682Reputation: 682Reputation: 682Reputation: 682
If you read the full article, they are using Heisenberg's Uncertainty Principle. If someone tries to tap in, the properties of the photon will be changed.

I think that the Uncertainty principle states that you can't determine one property such as phase without changing another property such as momentum. They are only concerned with measuring a single property, so if the others are changed that's OK.

My main point is that this is a theoretical conflict between quantum theory and relativity. It would be interesting if this quantum effect can be realized and used.

---

Scanning through the wiki article (thanks for that link) there is this quote:
An example of a pair of conjugate variables is the x-component of angular momentum (spin) vs. the y-component of angular momentum.

Last edited by jschiwal; 01-20-2005 at 06:56 PM.
 
Old 01-20-2005, 11:06 PM   #5
Capt_Caveman
Senior Member
 
Registered: Mar 2003
Distribution: Fedora
Posts: 3,658

Rep: Reputation: 69
I read about an interesting experiment that a group from UMBC performed early on in the entanglement work. They basically made entangled photon pairs and then sent them through a beam splitter so that the members of each pair went in different directions. In one direction, the photons passed through a filter that absorbed photons, except that the letters UMBC were cut out of the filter and some of the photons would pass through the letters. The other member of each pair went of in a different direction to a detector. When they measured the non-filtered photons, they formed the image "UMBC". Pretty freaky.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
DISCUSSION: Faster and Faster Compilation jeremy LinuxAnswers Discussion 5 12-06-2005 01:41 AM
Quantum GIS Dependency conflict on Suse 9.2 suse2166 Linux - Software 6 03-20-2005 02:53 PM
bandwidth management,htb, r2q?? quantum?? kartheekpn Linux - Networking 1 03-18-2005 12:32 PM
quantum fireball linux install problem attika Linux - Hardware 2 03-02-2003 01:38 AM
How to install Linux under Quantum Disk manager shassouneh Linux - Hardware 3 03-16-2002 05:37 AM

LinuxQuestions.org > Forums > Non-*NIX Forums > General

All times are GMT -5. The time now is 02:35 PM.

Main Menu
Advertisement
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Open Source Consulting | Domain Registration