The potential of quantum computing has been hailed as revolutionary, capable of transforming the way everything in our world works by finding solutions that are exponentially faster than today’s most powerful supercomputers.
But while business executives calculate the potential revenue that quanta could generate and journalists struggle to find simple ways to explain the complex processes behind them, quantum physicists are increasingly frustrated by their lack of understanding of their subject.
“Quantum computing is actually very different from our regular computing,” quantum physicist Shohini Ghose, a professor at Wilfrid Laurier University in Canada, told Euronews Next.
“It’s not just that this is a more powerful version of what we have today. It’s actually a completely different framework for the data processing itself.”
This framework is difficult to explain with simple analogies and familiar benchmarks.
A quantum computer is not X times more powerful than a normal computer. It’s not Real Madrid for your child’s soccer team. A quantum computer plays a very different game.
“It’s not like a quantum computer is better at every task and will somehow speed up everything we do,” Ghose said.
“There are very specific tasks that a quantum computer can actually do better.”
Understanding of the new framework of computing
Normal computers – from the ones we use at work to the record-breaking Frontier supercomputer – work by converting information into binary digits (ones and zeros) known as bits. You process long strings of these bits, called code, and use simple math to tell that code what to do.
A quantum computing framework is based on another fundamental unit of information called a quantum bit, which works on a principle called superposition.
“Imagine a situation where our bit is not quite a zero and not quite a one, but has some probability of being a zero and some probability of being a one,” Ghose said.
“That’s what we call superposition, and that’s how a quantum bit or qubit is described.”
That might sound less precise, but Ghose says it greatly expands the types of calculations a quantum computer can solve and, in many cases, increases the speed at which it can arrive at a solution.
“It’s almost like flowing from two points – 0 and 1 – in a landscape to anywhere in the landscape because any combination of zero and one is possible,” she said.
Game changing potential
So what can quantum computers do better than normal computers?
“If you’re just emailing, you’re not going to see tremendous acceleration that makes your emails faster or better,” Ghose said.
“But what could happen is that on the backend, a quantum encryption system could be able to improve the security and privacy of your communications.”
Quantum cryptography is an important area of research that relies on quantum mechanics to improve the security of online communications. Ghose says back-end quantum encryption could eventually be available on all of our devices.
“If this is done in a really bug-free and perfectly engineered way, it’s completely unhackable,” she said. “To break this encryption, you would have to break the laws of physics.”
Other applications depend on the ability to build large quantum computers. These could range from developing better medicines to building better solar cells and even clothing.
But to really expand the applications of quantum computing, experts from different fields must be involved in the research, according to Ghose.
“You don’t have to be a physicist to be part of this new quantum computing revolution,” she said.
“In fact, the more different groups of people can be involved, the richer the field and the more surprising the results.”
A long way for quanta
There are still many questions that need to be answered before quantum computing can reach the mainstream. First and foremost is the question of whether large quantum computers can be built at all.
“It’s not entirely clear if we can really scale them at all, because no one has been able to show conclusively that as we build ever larger quantum computers, we’ll be able to do so in a sustainable and scalable way.” ‘ Ghose said.
Qubits must be maintained at temperatures near absolute zero to function, making thermal management a major hurdle for designers to overcome.
Cost is also an issue – most estimates put the cost of a single qubit at around €10,000, putting a useful quantum computer for all industries out of the question.
But Ghose says the biggest challenge and unknown of quantum computing is how to deal with quantum errors.
“Part of what makes a quantum computer powerful is this particular phenomenon called entanglement, where all the different quantum bits talk to each other and connect in a way that they start acting as one,” she said.
“But if these qubits, instead of talking to each other, are talking to something outside of their computational space, like a random particle, they can also become entangled with those particles.”
In order to control the qubits and keep them from interacting with random particles, Ghose says they must be kept “colder than space.”
The only way to achieve this right now is to build giant computers “the size of an entire room” that fit all the hardware, electronics, and cooling systems.
“We have to do a lot of error corrections because they’re very, very vulnerable and even the smallest error or noise completely destroys the calculation,” Ghose said.
“We have to think about that as we move forward, is it really worth it? And if so, how do we do it responsibly and sustainably? I do not know the answer”.
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