'Self-correcting' gates advance quantum computing

Mar 12, 2009
Post-doctoral Fellow Kaveh Khodjasteh and Associate Professor of Physics and Astronomy Lorenza Viola (photo by Joseph Mehling '69)

(PhysOrg.com) -- Two Dartmouth researchers have found a way to develop more robust “quantum gates,” which are the elementary building blocks of quantum circuits. Quantum circuits, someday, will be used to operate quantum computers, super powerful computers that have the potential to perform extremely complex algorithms quickly and efficiently.

Associate Professor of Physics and Astronomy Lorenza Viola and Post-doctoral Fellow Kaveh Khodjasteh report their findings in the Feb 27, 2009 issue of . Their study is titled “Dynamically Error-Corrected Gates for Universal .”

The futuristic realm of quantum computing considers units of information called , or , which can be carried by quantum-mechanical objects such as electrons or atoms. Unlike today’s computers, which use of 0s and 1s, a quantum computer uses qubits that can each be in a superposition of 0 and 1. As a result, quantum computers could efficiently solve computational problems beyond the reach of today’s computers.

“An outstanding challenge stems from the fact that quantum bits are incredibly more prone to errors than their traditional-sized counterparts,” says Viola, who is the director of Dartmouth’s Quantum Information Science Initiative. “All quantum gates, the building blocks for implementing complex quantum-mechanical circuits, are plagued by errors originating from both the interaction with the surrounding quantum environment or operational imperfections.”

Viola’s and Khodjasteh’s study showed how to construct new quantum gates that can be “dynamically corrected” out of sequences from the available faulty gates. In this manner, the researchers say, the net total error is approximately canceled.

“The key idea is to carefully exploit known relationships between unknown errors,” says Viola. “Dynamically corrected gates allow for substantially higher fidelity to be reaching quantum circuits, and can thus bring the implementation of reliable quantum-computing devices closer to reality.”

Provided by Dartmouth College

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NeilFarbstein
1 / 5 (4) Mar 12, 2009
the incredible part; some believe that quantum teleportation is already causing telepathic phenomena where large amounts of coherent information are being transferred between people. There is some type of natural error correcting mechanism or quantum pheonomenon that like superconductivity causes long range cohenrency.
Smellyhat
5 / 5 (1) Mar 12, 2009
the incredible part; some believe that quantum teleportation is already causing telepathic phenomena where... [etc.]


That's not particularly incredible. "Some" is a group of people with a long track record of believing all sorts of thing.
nilbud
1 / 5 (1) Mar 13, 2009
NFarbstein what a wonderful world you live in, any time you have difficulty with reality just invent a whole new swath of "special" knowledge. Then you are the only one who knows and it takes as much effort as a children's fairytale.
johanfprins
1 / 5 (1) Mar 14, 2009
the incredible part; some believe that quantum teleportation is already causing telepathic phenomena where large amounts of coherent information are being transferred between people. There is some type of natural error correcting mechanism or quantum pheonomenon that like superconductivity causes long range cohenrency.

Long range coherency is found within a laser beam: It is wrong to claim that it also manifests within a traditional superconductor. In a traditional superconductor current is transported by correlated movement of adjacent charge-carriers: i.e. a local mechanism. Coherent superconduction is only possible when it occurs without having localised charge-carriers conveying the current.

The charge is then teleported across the phase. I have already generated this phase 8 years ago by extracting electrons with an anode from n-type diamond: When doing this and the electron density becomes high enough the electrons between the diamond and anode condense to form a single macro-wave. This wave is coherent and does therefore superconduct by teleportation (no local correlated movement of charge-carriers involved). This macro- electron wave is on a smaller scale like a covalent bond (2 condensed electrons) or a double bond (4 condensed electrons) or a triple bond (6 condensed electrons) except that consists of milliosn of electrons.

When such a wave exist of neutral matter, one obtains "dark matter". The latter should also be able to teleport: This could explain telepathy.
It is highly likely that a similar condensation of electrons form along a DNA string.