A quantum walk down Wall Street
Renaissance Technologies is rumoured to use methods from  topological quantum field theory.<p>They are fiercely and aggressively secretive, so no one really know for sure.<p>However, their founder worked in that field before moving to business:
<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Chern–Simons_theory" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Chern–Simons_theory</a><p>Famously, he was sacked by the NSA for giving an interview opposing US involvement in the Vietnam war.