In 1943, IBM’s first president, Thomas J. Watson, allegedly made this spectacularly incorrect prediction: “I think there’s a world market for maybe five computers.” In recent times, the authenticity of this quote has been contested as some believe Watson – if he did say it – was referring to adding machines the size of a house powered by large vacuum tubes.
Three years later, physicist, Sir Charles Darwin, who was director of the British National Physical Laboratory and grandson of the famous 19th century naturalist with the same name, wrote: “It is very possible that ... one machine would suffice to solve all the problems that are demanded of it from the whole country.”
Darwin too was terribly wrong. Regardless, there was simply no way either man could have predicted the tsunami of modern silicon chip-based servers, desktop PCs and mobile devices, such as the modern Apple iPhone, that would flood the world over the next 70 years.
And what a mighty wave it has been. In June 2008, Gartner predicted that there would be two billion PCs in use worldwide this year.
Now the world of computing is once again on the cusp of a revolution. And computers using quantum and nano technologies, in particular, may lead the way when microprocessor manufacturers finally reach their physical limits.
Quantum systems are based on the principles of quantum physics and work by generating complex calculations at the atomic and sub-atomic level. They promise a future where we have access to computational power well beyond the current capabilities of a traditional PC or supercomputer.
These machines have the potential to impact everything from modelling complex drugs to perhaps even one day unravelling the secrets of the universe. But the question is: How far off are we from having quantum systems available for commercial use?
Making it happen
Canadian firm, D-Wave Systems claims it has already commercialised a system using a subset of quantum mechanics called quantum annealing. Yet in February, researchers at the University of California and IBM questioned whether a D-Wave machine used by Google actually relies on quantum mechanics.
However long it takes for mass-produced quantum computers to become a commercial reality, academics at universities in Australia and abroad are leading the charge with their quantum discoveries.
Last November, researchers at the University of Sydney, the University of Tokyo and the Australian National University created the world’s largest quantum circuit board, an essential component in high-powered laser light computers.
During the experiment – which was proposed by Dr Nicolas Menicucci, a theoretical physicist from the University of Sydney’s School of Physics, and conducted at the University of Tokyo – 10,000 quantum systems were brought together in a single component.
Just over a year earlier, researchers at the University of New South Wales created the world’s first working quantum bit (qubit) based on a single atom in silicon. They say this will lead to the development of ultra-powerful computers in the future.
The research team was able to read and write information using the ‘spin’ or magnetic orientation of an electron bound to a single phosphorous atom embedded in a silicon chip. A month earlier, the team created a single-atom transistor, which they believe could be used as a building block for quantum computing.
Another team of researchers at the Australian National University, the National University of Singapore, and the University of Queensland suggested that background interference in quantum-level measurements – known as quantum discord – may be the key to unlocking quantum computing’s potential.
These are just a few examples of the research into future computing taking place worldwide. So why is there such a drive around quantum research when classical computers are still doing the job?
“Quantum computers are not yet at the level where they are doing problems that are too hard for a classical computer,” says the University of Sydney’s Dr Menicucci. “The regular computers we have currently outperform all existing quantum computers on tasks that have been done so far.”
But what quantum computers do have is the potential in the long-term to solve complex problems or algorithms that need to be massively scaled. “There are certain computing tasks that get much harder as you scale them up,” says Menicucci.
“Multiplying numbers is easy when it’s three times two. As the numbers get bigger, you may have to use a calculator, but even huge numbers are no problem; multiplication is relatively easy.
“But factoring whatever number you get out of that multiplication into the original numbers is a problem that our best algorithms are not very good at. As the number to be factored gets bigger, it becomes astronomically difficult to do. You can easily generate a modest-sized number that is so hard to factor, it would take the best supercomputer in the world longer than the age of the universe to factor it.”
But this is not true of a quantum computer, says Dr Menicucci. “One of the things that a quantum computer can do very quickly, if we could build one, is factor these very large numbers. We don’t know of a way a classical computer can do that in an efficient way if the number gets big.”
Everything is quantum
Everything in the world is quantum – all matter, all energy obeys quantum mechanics, continues Dr Menicucci. “The question is: ‘Why don’t we see these quantum effects in our daily life? Why do we have to work so hard to engineer them?’”
The answer, as Dr Menicucci explains, is that you need “very fragile states” to see quantum effects. “Think about it in terms of a deck of playing cards – if you take out the cards, throw them on a table randomly and someone walks by and creates a small breeze, nothing happens to the cards.
“If someone sneezes, maybe they move a little bit but not much really changes. But if you take those cards and carefully arrange them into a pyramid and someone walks by, bumps the table or sneezes, it’s all gone.”
One configuration of the cards is robust and the other is fragile, Dr Menicucci says. “Quantum physics is like that in the sense that quantum computers need very fragile quantum states – known as entangled states – to do their calculations.”
Despite the obvious difficulties of keeping fragile quantum states together, research around information processing is showing real promise. But researchers need new theoretical developments and experimental breakthroughs to make it work.
“The first ordinary computers were room size, inefficient and broke down,” Dr Menicucci says. “We’re not even at that level yet, we’re at the level of just designing and making robust the individual ‘vacuum tubes’ of a quantum computer, if you will – and testing them in small quantum devices.”
According to Dr Menicucci, a lot of work remains to be done to scale these quantum machines to be capable of tackling real-world problems. “The rest of the world is walking by our house of cards, sneezing on it and knocking it over. That’s a phenomenon called ‘decoherence’… and it shows up as noise that ruins your computations,” he says.
“Figuring out clever ways to fight decoherence is one of the main things that both theorists and experimentalists are working on right now.”
Next up: Leading the way