February 25, 2006
More on the University of Illinois at Urbana-Champaign Quantum Computer Experiment
From Nature, a more descriptive article on the quantum computer that can solve problems before even running:
A quantum computer is very different from a traditional desktop computer. It uses the laws of quantum mechanics to perform many calculations at once where a conventional computer could do them only one at a time. This drastically cuts the time a quantum computer takes to find the answer.This is made possible by the fact that quantum objects, such as individual atoms or photons of light, can be placed in 'superposition' states, mixtures of states that are mutually exclusive in everyday objects. A quantum switch, for example, could be simultaneously on and off.
That's the key to quantum computation, because it means that a quantum computer can be placed in a superposition of states where it is running and not running. This leaves an imprint of the 'running' state on the history of the 'not running' state, such that one can look at the latter and determine something about the former.
"Some people like to think of this as two different universes", explains computer scientist Richard Josza of Bristol University in England. In one universe the computer runs, while in a parallel universe it doesn't.
One might say then that the computer does actually run, but in a 'parallel universe'. "So you wouldn't be charged for the cost of running it," says Josza.
Posted by Robin Varghese at 01:35 PM | Permalink
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Listed below are links to weblogs that reference More on the University of Illinois at Urbana-Champaign Quantum Computer Experiment:
» Quantum interrogation from Cosmic Variance
Quantum mechanics, as we all know, is weird. Its weird enough in its own right, but when some determined experimenters do tricks that really bring out the weirdness in all its glory, and the results are conveyed to us by well-intentioned but o... [Read More]
Tracked on Feb 27, 2006 3:05:03 AM
» Thinking is hard work from Watermark
Whew! First, from 3 Quarks, there was this, and then this, and then I asked (only half-joking) if they were joking, and Abbas Raza promised a plain-language explanation -- and kept his promise. So now there is this, from Cosmic Variance. I have read it... [Read More]
Tracked on Mar 2, 2006 11:19:13 AM
» Thinking is hard work from Watermark
Whew! First, from 3 Quarks, there was this, and then this, and then I asked (only half-joking) if they were joking, and Abbas Raza promised a plain-language explanation -- and kept his promise. So now there is this, from Cosmic Variance. I have read it... [Read More]
Tracked on Mar 2, 2006 11:20:55 AM





Comments
OK, I am not a physicist, and can't pretend to understand this -- but these folks are joking with us, right?
Posted by: SB | Feb 25, 2006 3:44:11 PM
without even turning off my computer I can easily generate a counterfactual statement to the effect that this experiment proves nothing.
T
Posted by: Thomas | Feb 26, 2006 2:24:19 PM
This is no joke, but it IS so unintuitive, that without learning a lot of the math of quantum theory it is almost impossible to understand.
I have asked Sean Carroll (a very well-respected physicist) at Cosmic Variance to explain this to us in as plain language as possible, and he has agreed to do so later in the week. I will post it when it becomes available.
Posted by: Abbas Raza | Feb 26, 2006 4:38:22 PM
Oh, thank you!
Posted by: SB | Feb 26, 2006 11:55:14 PM
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