“Grit in the Gears” Costs Energy in Modular Information Systems

Digital information may appear to exist as abstract ones and zeroes, flipping effortlessly from one to another. But in fact there is a minimum amount of energy required to run any computation system, regardless of how “energy efficient” are its component parts. A recent paper from Jim Crutchfield and Alex Boyd at the UC Davis Complexity Sciences Center with Dibyendu Mandal at UC Berkeley shows that there is some inescapable friction, or “grit in the gears” between the levels of organization in an information system.

Reversing Cause And Effect Is No Trouble For Quantum Computers

Watch a movie backwards and you’ll likely get confused – but a quantum computer wouldn’t.

In research published 18 July in Physical Review X, an international team shows that a quantum computer is less in thrall to the arrow of time than a classical computer. In some cases, it’s as if the quantum computer doesn’t need to distinguish between cause and effect at all.

We find it easier to understand events in time sequence, but a quantum computer may not be so limited, say researchers at UC Davis and the National University of Singapore. Image by Aki Honda/Centre for Quantum Technologies, National University of Singapore.