Quantum computing is closer to reality

July 7, 2008

by Mark Ollig

To find a telephone number for a particular name in the phone book, a computer would look at all the names – one at a time – until it came across the right number.

The computer is fast, but it is still searching in a “sequential” manner as it needs to check each name to find the correct number.

When using a “quantum” computer, all of the names in the phone book would be checked exactly at the same time.

This is the result of a quantum computing operation happening instantly.

Considered science fiction just a few years ago, today quantum computing is moving just a little bit closer to reality.

I was looking over a Nature Physics article recently and the researchers at Purdue University talked about a new hybrid molecule they created on an experimental computer chip made of silicon.

This molecule allows the control of what they called the ‘quantum state’ which is needed in order to build quantum computers in semiconductors.

The researchers believe the creation of this hybrid molecule opens that door.

“Up to now large-scale quantum computing has been a dream,” says Gerhard Klimeck, professor of electrical and computer engineering at Purdue University.

Computers today work pretty much the same way as they have over the last fifty years.

A computer still uses those ones and zero bits to store and process information.

Quantum computing using quantum physics, would process information using “quantum bits,” or what are called “qbits.”

“If you want to build a quantum computer you have to be able to control the occupancy of the quantum states,” Klimeck says. “We can control the location of the electron in this artificial atom and, therefore, control the quantum state with an externally applied electrical field.”

This gets into some very deep subjects like quantum mechanics, and quantum physics – disciplines needed to be mastered by scientists and these researchers.

“This development may not bring us a quantum computer 10 years faster, but our dreams about these machines are now more realistic,” Klimeck concluded.

In concept, two quantum computers could communicate instantaneously across any imaginable distance – even across different planetary solar systems, which is contrary to what today’s physicists understand.

This “neither here nor there” quantum state is what can be controlled in the new hybrid molecule by altering the voltage of the transistor.

The quantum state reminds me of an original Star Trek episode about the “dimensional corridor” buffer between universes. The episode was called “The Alternative Factor.”

It is interesting to note Albert Einstein wrote in the mid 1930s that in a “quantum state,” “a keg of gunpowder would have both exploded and unexploded molecules within it.”

Einstein was talking about the quantum superposition, which is one of the fundamental laws of quantum mechanics.

Quantum mechanics is the study of mechanical systems (physics) whose proportions are similar to or below the atomic scale. This includes those molecules, atoms, electrons, protons and other subatomic particles that are “very small.”

Physicist Lloyd Hollenberg and colleagues at the University of Melbourne in Australia have constructed a theoretical silicon-based quantum computer chip.

“The team found that the measurements only made sense if the molecule was considered to be made of two parts,” Hollenberg says. “One end comprised the arsenic atom embedded in the silicon, while the ‘artificial’ end of the molecule forms near the silicon surface of the transistor. A single electron was spread across both ends.

“What is strange about the ‘surface’ end of the molecule is that it occurs as an artifact when we apply electrical current across the transistor and hence can be considered ‘manmade.’ We have no equivalent form existing naturally in the world around us.” Hollenberg said.

Meanwhile, in the Netherlands, Sven Rogge and his fellow researchers at Delft University of Technology were experimenting with nano-scale transistors.

They found properties in the transistor which showed electrons being transported by a single atom, but it was uncertain what exactly was causing this effect.

“Our experiments made us realize that industrial electronic devices have now reached the level where we can study and manipulate the state of a single atom,” Rogge says. “This is the ultimate limit; you cannot get smaller than that.”

If you want to read more about quantum computing, check out this link to the Purdue University at: http://tinyurl.com/4mg7ju

For the first time I am using what is called a “tiny url.” This is a process I found which compresses and shortens any long Internet URL link to make it easier to type into your browser and still get to the same place.

The tiny URL link to the Nature Physics is: http://tinyurl.com/yzf3uh