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.

Not Gate?

[NoMercy]

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

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.