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Researchers use a pair of entangled photons and fiber strands to create basic quantum computer

Researcher Prem Kumar, the AT&T Professor of Information Technology in the Department of Electrical Engineering and Computer Science and the director of the Center for Photonic Communication and Computing, and his research team are now one step closer to making quantum computers a reality.

Kumar and his team have demonstrated a basic building block of a quantum computer using entangled photons generated in optical fibers. Kumar says, “Because it is done with fiber and the technology that is already globally deployed, we think that it is a significant step in harnessing the power of quantum computers.”

With the computers we use today, data is processed in bits that consist of ones and zeros, or on and off states. In quantum computing, quantum bits, also known as qubits, are used that can exist in a one or zero state as well as a third state known as a “superposition.” This superposition is where a quantum computer gets the huge performance gains over current, traditional computers. The superposition allows the qubit to be both a one and zero simultaneously allowing the computer to process more information, much faster than computers today can.

Kumar and his team used a pair of photons and have been able to entangle the pair of photons in an optical fiber using the fiber’s nonlinear response. The researchers also say that the photons remain “mysteriously” entangled no matter how far you separate the two in the transmission fibers.

In the project, Kumar and his team were able to use the photons to perform a basic quantum computer task, a controlled-NOT gate, allowing two photonic qubits to interact. Kumar said in a statement, “This device that we demonstrated in the lab is a two-qubit device — nowhere near what’s needed for a quantum computer — so what can you do with it? It’s nice to demonstrate something useful to give a boost to the field, and there are some problems at hand that can be solved right now using what we have."

DailyTech reported in October of 2007 that another team of researchers working on quantum computing had been able to devise a method of controlling the spin of single electrons.

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RE: Hold on a second here
By masher2 (blog) on 4/9/2008 1:15:51 PM , Rating: 5
The difference here is that a trinary system of 64 bits can be in any of 3^64 possible states -- but only one such state at a time.

A 64-qubit quantum computer, however, can exhibit 2^64 possible states...and can be in all those states at the same time. (specifically, a linear superposition of all possible states).

A trinary system is no different than a traditional binary computer, in that it has to process each state consecutively. A quantum computer can perform operations on all states simultaneously...which makes it incredibly fast for tasks such as factoring.

RE: Hold on a second here
By murphyslabrat on 4/9/2008 1:26:00 PM , Rating: 2
There we go. In almost every article I have read about it, they're always describing it like a trinary system. Thanks for the clarification.


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