Quantum Computer vs. Conventional Computer: Scientist Tests Which is Speedier

Quantum computers have long been heralded as the theoretical supercomputers of our age. Now, though, researchers have found further proof that quantum computing systems will be able to outperform conventional computing methods. They've discovered that quantum computing is far faster than tradition computing, which could mean for some speedy calculations in the future.

In order to determine exactly how quantum computers match up to regular computers, Catherine McGeoch, the researcher conducting the study, tested a quantum computer system produced by D-Wave just outside Vancouver. This particular system had a thumbnail-sized chip that was stored in a dilution refrigerator within a shielded cabinet at near absolute zero in order to perform its calculations. While conventional computing is binary (which uses the typical 1s and 0s), quantum computing relies on the fact that subatomic particles inhabit a range of states. Different relationships among these particles may coexist, and the probable states can be narrowed in order to determine an optimal outcome among a near-infinitude of possibilities.

In order to compare this quantum computer against a traditional one, McGeoch designed experiments that would test the machines. She found that the D-Wave actually excelled at calculations that involved a specific combinatorial optimization problem, comparable in difficulty to the famous "travelling salesperson" problem that's been a foundation of theoretical computing for decades. This particular problem asks the question: Given a list of cities and the distances between each pair of cities, what is the shortest possible route that visits each city exactly once and returns to the original city?

The fact that the quantum computer was particularly adept at solving this type of problem has important implications for its future use. This type of logic applies to shipping logistics, flight scheduling, search optimization, DNA analysis and encryption and more. The computer could potentially be used to solve important equations that could further scientific research.

McGeoch may have found that the quantum computer was useful at solving some problems, but it's not meant to replace a conventional computer for every task.

"This type of computer is not intended for surfing the internet, but it does solve this narrow but important type of problem really, really fast," said McGeoch, the Beitzel Professor in Technology and Society at Amherst, in a news release. "There are degrees of what it can do. If you want it to solve the exact problem it's built to solve, at the problem sizes I tested, it's thousands of times faster than anything I'm aware of."

While it's thousands of times faster at some problems, though, it's a bit slower when it comes to more general problems of that size. The quantum computer is merely above average when it solves these more general problems.

Even so, this type of computing could have an important use in future problems. The fact that it is so much faster than conventional methods could have important implications for the future.

The findings will be presented at the peer-reviewed 2013 Association for Computing Machinery International Conference on Computing Machinery in Ischia, Italy.