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Quantum computing will allow unique solutions to problems via quantum superposition -- the potential for a set of bits to exist in multiple states at once. Quantum algorithms could crack eventually crack even the best "unbreakable" current cryptography with ease.  (Source: UIUC Physics Department)

A Yale team has released the first quantum computer chip to be reported in peer-reviewed literature. The new chip uses aluminum atoms, silicon, and quantum interconnects. It has only 2 qubits. A Canadian company has also laid claim to the title of the world's first quantum processor, but its work has not been peer reviewed.  (Source: Blake Johnson/Yale University)
Does Yale have the world's first solid state quantum processor on their hands?

Quantum computing has the potential to easily crack current cryptography systems, simulate chemical and nanochemical quantum systems, and speed up the search for solutions of certain types of math problems called NP Complete problems.  Many have raced to create the world's first quantum processor.

In 2007 D-Wave, a Canadian firm, claimed to have created the world's first quantum computing chip.  Debate about whether the chip is a true quantum computer has raged, while the company has continued to release claims of improved "quantum chips" -- with the latest being a 128 qubit chip.  Researchers, though, are skeptical of these claims.

Now, researchers at Yale University claim that they have created the world's first solid state quantum processor.  The new chip, at the very least is the first processor to be officially reported in a peer-reviewed journal.  The research appears in the journal Nature's June 28 advanced publication listing.

The chip is composed of 2 qubits ("quantum bits").  Each qubit is composed of billions of aluminum atoms.  Qubits are different than traditional bits, in that while they can hold a value of one or zero, they can also hold a superposition of both states.  Essentially, this means that the two qubit chip can hold 4 simultaneous states, while a 2 bit chip could only hold 1 state (with four possibilities). 

Thus the use of qubits enables multiple tests with a single value.  For example if you had four phone numbers and one belonged to your friend a traditional processor would typically require a call to a couple of numbers before the correct one was found.  According to Yale Professor of Applied Physics and Physics Robert Schoelkopf, "Instead of having to place a phone call to one number, then another number, you use quantum mechanics to speed up the process.  It's like being able to place one phone call that simultaneously tests all four numbers, but only goes through to the right one."

The researchers used the new chip to run elementary algorithms, such as a simple search, based on this concept.  States Professor Schoelkopf, "Our processor can perform only a few very simple quantum tasks, which have been demonstrated before with single nuclei, atoms and photons.  But this is the first time they've been possible in an all-electronic device that looks and feels much more like a regular microprocessor."

The qubit processor communicates via a "quantum bus" which sends signals by photons.  The key breakthrough that allowed the creation of the chip, according to the team, was the ability to fix atoms in a specific quantum state for longer.  When qubits were first manipulated a decade ago, they would only last up to a nanosecond -- the Yale team got them to last for a microsecond, long enough for computing purposes.

The Yale researchers look forward to prolonging the states even further, to allow more complex algorithms. They also hope to add more qubits to their design.  The team writes that scientists are "far away" from a practical quantum computer, still, though.  And in laying claim to the world's "first" quantum computer chip, they're essentially throwing down the gauntlet with D-Wave, effectively accusing them of peddling snake oil to the corporate world.



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RE: Consequences for encryption
By rvd2008 on 6/29/2009 5:55:51 PM , Rating: 3
Quantum computers, when ready, will bring us quantum encryption. If I remember correctly from quantum mechanics, you can not observe a particular state without disturbing the state itself. Quantum encryption is unbreakable AFAIK.


RE: Consequences for encryption
By MrPoletski on 6/30/2009 4:09:50 AM , Rating: 3
quote:
Quantum encryption is unbreakable AFAIK.


Then how does the message recipient read the message?

No encryption is unbreakable.


By foolsgambit11 on 6/30/2009 5:47:50 AM , Rating: 5
One-time pads are unbreakable, when created truly randomly, used correctly - i.e., one time - and when the pad is kept secure.

We have to make the distinction between breaking an encryption only by receiving the encoded message, by intercepting the cypher key, by gaining access to the message before it is encoded or after it is decoded, or any other method. Although all of these methods may allow a third party access to the data, I'd only call the first truly 'breaking' the encryption. (Is it really breaking the encryption if you know the key before you start?) The rest are breaking other portions of the security protocol.

Quantum cryptography, as currently envisioned, isn't encryption so much as it is a very secure method of agreeing on and transmitting a one-time pad key for use in encryption. It can theoretically ensure that a suitable one-time pad is delivered without being intercepted to any degree of certainty short of unity desired - true, that isn't completely unbreakable, but it's close enough to certain to keep people from trying. Unfortunately, in practice, since you can't perfectly transmit quantum states without some degradation, photon emitters sometimes emit more than one photon at a time, &c, there are some potential avenues for approach in the error-checking process. Plus, you could always be subjected to a denial-of-service style attack, with somebody constantly snooping just to ensure you can never agree on a key, or just cutting the lines. But none of that is really breaking the encryption.

So, I guess what I'm saying is that there is such a thing as unbreakable encryption, but there isn't such a thing as perfectly safe encryption. You just have to try means other than cracking the encryption. Maybe that's splitting hairs, though.


By foolsgambit11 on 6/30/2009 5:17:07 AM , Rating: 2
As far as you and anybody else knows. The laws of physics as we understand them at the moment make it possible to create an 'unbreakable' cypher by creating a one-time pad style cypher key as long as the message. Unlike traditional one-time pads which require a secure method of delivering the cypher key to the recipient, quantum mechanics allows a key to be agreed on securely by both sender and receiver, while also ensuring nobody can eavesdrop. And this has already been demonstrated at distances of nearly 100 miles over fiber optic line.

'Unbreakable' is in quotes, because there is some information that is possible to be gleaned from the data exchange using current methodology. It is almost certainly not enough to crack most cyphers, but you never know.

Check out the Wikipedia article:
http://en.wikipedia.org/wiki/Quantum_cryptography


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