http://science-beta.slashdot.org/story/14/12/03/1551239/mathematical-trick-h... <http://beta.slashdot.org/%7ESoulskill>Soulskill posted about an hour ago | from the still-slower-than-a-12-year-old dept. <http://beta.slashdot.org/index2.pl?fhfilter=math> Math <http://beta.slashdot.org/index2.pl?fhfilter=math> <http://science-beta.slashdot.org/story/14/12/03/1551239/mathematical-trick-helps-smash-record-for-the-largest-quantum-factorization>16 <http://beta.slashdot.org/%7EKentuckyFC>KentuckyFC writes: One of the big applications for quantum computers is finding the prime factors of large numbers, a technique that can help break most modern cryptographic codes. Back in 2012, a team of Chinese physicists used a nuclear magnetic resonance quantum computer with 4 qubits to factor the number 143 (11 x 13), the largest quantum factorization ever performed. Now a <http://arxiv.org/abs/1411.6758>pair of mathematicians say the technique used by the Chinese team is more powerful than originally thought. Their approach is to show that the same quantum algorithm factors an entire class of numbers with factors that differ by 2 bits (like 11 and 13). They've already discovered various examples of these numbers, the largest so far being 56153. So instead of just factoring 143, <https://medium.com/the-physics-arxiv-blog/the-mathematical-trick-that-helped-smash-the-record-for-the-largest-number-ever-factorised-by-a-77fde88499>the Chinese team actually quantum factored the number 56153 (233 x 241, which differ by two bits when written in binary). That's the largest quantum factorization by some margin. The mathematicians point out that their discovery will not help code breakers since they'd need to know in advance that the factors differ by 2 bits, which seems unlikely. What's more, the technique relies on only 4 qubits and so can be easily reproduced on a classical computer. --- co-chair http://ocjug.com/