Quantum Logic Gate Created Using Excitons

Roland Piquepaille writes "In this article, PhysicsWeb reports that researchers in the U.S. "have taken another important step towards making a quantum computer. [They] have created a logic gate using two electron-hole pairs -- also known as "excitons" -- in a quantum dot." According to Wikipedia, "an exciton is a combination of an electron and a hole in a semiconductor or insulator in an excited state These physicists from the University of Michigan and other labs made a quantum dot by using a thin gallium arsenide layer stuck between two aluminium gallium arsenide barriers. And electrons trapped in the middle layer were excited by light to create a quantum logical gate with four states. The group says this could be useful "in other approaches to quantum computing based on the optical control of electron-spin qubits in quantum dots.." This summary contains more details."

Comments

Is this for quantum or electronic computers?

[Urkki]

So they have a quantum gate. But is it just a transistor replacement, which you still would use to build traditional computers, chomping through processor instructions, processing binary (or base 4 or whatever) numbers? Or is for quantum computers working on a completely different paradigm?

Not quite yet

[cybermace5]

It's nicely done, but not the breakthrough that means quantum computers for all. It is, after all, only a NOT gate. I barely consider NOT as a logic function...more like half a function.

True discovery? or just an interesting find?

[VisualStim]

Although it will not be possible to scale up the system, the group says that many of the ideas and techniques they have developed could be useful in other approaches to quantum computing based on the optical control of electron-spin qubits in quantum dots.

So ... maybe this is useful ... maybe not. Not even the researchers know. Don't read too much into this "discovery". :)

Not Gate?

[NoMercy]

Call me when they make NAND gates with a way to couple them together, then I'll get excited.

Re:In the future!

[ikkonoishi]

Maybe there will be serveral types, and Intel works with one type of qubit logic and AMD works with a different.

Grr..
Non standardized interfaces make Hulk angry!
Hulk smash puny op-codes

Seriouly though I think we should have some people theorizing the needed logic models at the same time as they develop the actual hardware components. Otherwise we will end up with >10e30 different implementations which set computing back decades.

Just my 1.29 cents.

Is it really a 4-state gate?

[Sherloqq]

After all, they say they're using "two electron-hole pairs", so doesn't that translate into 2 two-bit "registers" instead of a single four-bit one? End result is the same, mind you, but the method is different.