A math problem developed 243 years ago can be solved only by using quantum entanglement, new research finds.

The mathematics problem is a bit like Sudoku on steroids. It's called Euler's officer problem, after Leonhard Euler, the mathematician who first proposed it in 1779. Here's the puzzle: You're commanding an army with six regiments. Each regiment contains six different officers of six different ranks. Can you arrange them in a 6-by-6 square without repeating a rank or regiment in any given row or column?

Euler couldn't find such an arrangement, and later computations proved that there was no solution. In fact, a paper published in 1960 in the Canadian Journal of Mathematics used the newfound power of computers to show that 6 was the one number over 2 where no such arrangement existed.

Now, though, researchers have found a new solution to Euler's problem. As Quanta Magazine's Daniel Garisto reported, a new study posted to the preprint database arXiv finds that you can arrange six regiments of six officers of six different ranks in a grid without repeating any rank or regiment more than once in any row or column … if the officers are in a state of quantum entanglement.

To read more, **click here.**