New Processor Chip Uses Light, Exponentially Faster

Dennis Faas's picture

British computer researchers have produced a tiny microchip capable of using light rather than electricity to carry out calculations. It employs quantum mechanics to drastically cut the time taken for computations and could one day mean a substantially more secure Internet.

University of Bristol researchers say the small size of the chip is the easiest change to demonstrate, but that this isn't its real innovation. And they are open about the fact that it won't replace standard computer processors. But the principle of what it does do is a genuine breakthrough.

Exponentially Faster than Standard PCs

The chip utilizes something called Shor's algorithm: a method used to compute sets of two whole numbers that multiply together to make a given number. What's important to recognize here is that Shor's method is exponentially faster than the most efficient known classical factoring algorithm, which means it's possible to 'break' widely used public-key cryptography, such as a scheme known as RSA.

RSA is based on the assumption that factoring large numbers is computationally infeasible, even for a standard PC. This assumption is valid for classical computers; however, Shor's algorithm shows that factoring is efficient on a quantum computer, so an appropriately large quantum computer can 'break' RSA. (Source:

Chip uses Quantum Mechanics

The new chip works through quantum mechanics, and is based on the fact that photons (effectively the smallest part of what makes up light) can exist in more than one state at a time.

Instead of electrical charges, the chip uses four photons and a series of mirrors. The quantum nature of the photons means the chip can try out multiple possible solutions simultaneously, drastically speeding up the process of solving the algorithm. (Source:

Because the chip uses light rather than electrical circuitry, it should be much easier to increase its capacity to deal with larger numbers. That means that, although it could take two decades to make a chip powerful enough for practical use, the technology could eventually make it possible to carry out calculations more complicated, and more quickly, than could ever be possible with an electrical processor chip.

The most likely use of the optical processor would be to greatly increase the level of encryption that can be applied to computer data. That in turn could greatly increase the security of online transactions and make Internet shopping and banking far safer. (Source:

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