Molecular computer mimics human brain

Processor can solve complex problems, even heal itself

A superthin computer just two molecules thick can solve complex problems and, somewhat like the human brain, can evolve to improve and perform many operations simultaneously.

This molecular processor can also heal itself if there is a defect, researchers added.

Modern computers operate at staggering speeds, capable of carrying out more than 10 trillion instructions per second. However, they generally perform operations in sequence, one thing at a time. 

Brain cells or neurons, fire "only" 1,000 times per second or so, but the fact that millions of them simultaneously work in parallel means they can complete tasks more efficiently than even the fastest supercomputer.

The connections between neurons also evolve over time, growing stronger or weaker as the brain works out the best way to solve problems. In this way, such networks can learn over time.

A molecular computer
Now an international research team from Japan and the United States has created a computer just two molecules thick that can replicate these traits of the human brain to a certain extent.

The building block of this computer is an organic compound known as 2,3-dichloro-5,6-dicyano-p-benzoquinone, or DDQ for short. This molecule can basically switch between four different electrically conductive states — think of a ring with four spokes.

The scientists deposited molecules of DDQ onto a surface of gold, which then spontaneously assembled into two layers, each a hexagonal grid of molecules.

The researchers next used the electrically charged tip of a scanning tunneling microscope to individually set molecules in the top layer to a desired state, essentially writing data into the system. (A scanning tunneling microscope operates somewhat like a blind person's fingers do with Braille writing — moving over a surface to detect microscopic bumps and valleys.)

Each molecule could wirelessly interact with its neighbors via their electric fields. These molecules continuously exchanged information in the form of electrons among themselves, at times causing molecules around them to change states. This is similar to how electricity flowing down wires makes transistors in microchips switch back and forth to encode data as ones or zeroes.

The results were patterns such as lines, triangles, hexagons and rhombuses, where each molecule within is set to a certain state.

Massively parallel Altogether, at least 300 molecules in the system interact together like a massively parallel computer, each changing states when data is written into the system. The patterns or "cellular automata" that result among the molecules function much like circuits on chips to direct the flow of electricity. The difference is that in this system, the patterns can evolve over time as new data is entered.

Also, like the brain but unlike other existing manmade computers, this new system can heal itself because the molecules that make up the computer can automatically reorganize themselves.

"This is brain-like computing," said researcher Ranjit Pati, a physicist at Michigan Technological University.

To probe the molecular computer's power, the researchers used it to successfully simulate two natural phenomena: the way heat diffuses through a material, and the way cancers grow in the body.

In principle, this new computer could also serve as a means to solve problems that conventional computers find too hard to tackle, "intractable problems that are considered impossible to finish within a finite time," explained lead researcher Anirban Bandyopadhyay, a physicist at the Japanese National Institute for Materials Science in Tsukuba.

These might include predicting the behavior of systems with many interacting bodies — anything from disease outbreaks to the evolution of galaxies, Michigan's Pati said.

One important weakness of the system is how it depends on scanning tunneling microscopy, which is a slow process. In the future, it may be possible to use multiple tips to simultaneously scan many molecules at one time, Pati suggested.

Since these molecules assemble themselves into grids, scaling them up to a larger system will not be a problem. The team's next target is a computer employing 1,000 molecular switches.

 

More studying 'on home computers'

Pupils are more likely to use computers for their schoolwork at home on a daily basis than they are to use them every day at school, according to a survey.

A study carried out in the UK for technology company Microsoft showed 37% of secondary pupils used computers for study every day at home.

This is a more intensive use than at school - where 30% of pupils were using computers each day.

The survey considered the computer use of 512 families with children.

The study reveals the increasingly pervasive use of technology for homework by pupils in their own homes.

Playing on the computer

Among these secondary level pupils, aged between 11 and 18, more than 90% used a home computer for schoolwork at least once a week.

And more than a third were using their family's computer for homework or revision every single day.

There have been concerns about the "digital divide" - in which children from better-off families get an advantage in school from better computer equipment at home.

The government says there are about a million children without the internet at home - leaving them at the other end of the scale from the two in five pupils who are using computers at home every day for schoolwork.

As well as using computers for homework, they have become a major feature of leisure time - identified by 71% of young people as being among their favourite activities.

Parents also use computers as a leisure activity - but at a lower level than their children - with 65% saying it was one of their favourite activities.

There is also a strong belief among parents that having a computer at home is valuable to their children's education.

'Essential as pen and paper'

Microsoft's Ray Fleming suggests that the higher levels of computer use at home for schoolwork by pupils is a reflection of the limitations on computer use in school.

Young people say computer use is one of their favourite activities

"School use of information technology can be very scheduled - it's often structured around particular lessons," he says.

At home children look for information on the computer in a more informal way, he says.

And he forecasts that this trend for studying at home with a computer will increase.

"There is an increasing blurring between learning-time and leisure-time and so computers in the home are becoming as important as those in the classroom," he says.

The widespread availability of computers at home also raises questions about handling this information.

"There are so many sources of information, that the challenge now is not about finding information but finding the most useful questions," he says.

Earlier this month the government announced a £300m Home Access scheme to give a laptop to 270,000 low income families and free broadband access.

Children's Secretary Ed Balls said that being without the internet at home leaves pupils "at a disadvantage to their peers".

"Computers are no longer a luxury for the few, but are as essential a part of education as books, pens and paper."