# If Your Computer Existed In Multiple Universes, It Would

Theoretical physicist Brian Greene gives a crash course on quantum computing in 2 minutes. Read more at BigThink.com: http://ift.tt/1H1oD7G Follow Big Think here: YouTube: http://goo.gl/CPTsV5 Facebook: http://ift.tt/1qJMX5g Twitter: https://twitter.com/bigthink Transcript - A quantum computer is a device, a technological device that in principle would harness the full capacity of quantum mechanics to undertake calculations that a standard computer would be absolutely unable to achieve. One way of thinking about it is this. There’s an approach to quantum mechanics where one imagines that there are many in some sense parallel realities moving along in some larger environment if you will. Where, for instance if I want to measure an electron, quantum theory says well there’s a 50 percent chance it’s there and a 50 percent chance it’s over there. Now what does that mean? Well one interpretation says well there’s actually two universes and in one universe the electron is here and in another universe it is over there. That’s kind of a crazy sounding idea but a quantum computer perhaps can harness that by doing some calculations over here and other calculations over there in parallel. Now it’s doing in some sense twice as many calculations as a classical computer existing in one world would be able to do. Now imagine taking that idea and spreading it over all of the possible realities allowed by quantum mechanics. Now you’re harnessing all of these different worlds if you will to do all of these calculations in parallel much faster, much more powerful. Doing calculations that in a single universe would be impossible. So this is one way of thinking about it and it offers amazing possibilities and we just need to see how successful we are at harnessing these ideas to actually put it into practice. And we don’t know yet. We’ll see going forward but it’s an exciting possibility.