A well-known problem called the “party problem” asks what the minimum number of guests you would need to invite to a gathering to ensure that a small subset is made of people who all know each other and another who all don’t. Solutions to this problem are given in what’s known as Ramsey numbers. Calculating the minimum number of guests to ensure groups of three strangers and three friends is fairly easy (the answer is six). But increasing the number of people makes the solution increasingly hard to calculate, with most Ramsey numbers being beyond the capability of our current computers.
D-Wave’s device was able to implement an algorithm to calculate Ramsey numbers for different configurations, though none that weren’t already known from previous work. The findings appeared Sept. 25 in Physical Review Letters.