A recent paper from Dr. Lloyd discusses limits to digital computation as we now employ it, but he further shows that the universe itself is a sort of vast quantum computer.
“This article reviews the history of digital computation, and investigates just how far the concept of computation can be taken. In particular, I address the question of whether the universe itself is in fact a giant computer, and if so, just what kind of computer it is. I will show that the universe can be regarded as a giant quantum computer. The quantum computational model of the universe explains a variety of observed phenomena not encompassed by the ordinary laws of physics. In particular, the model shows that the the quantum computational universe automatically gives rise to a mix of randomness and order, and to both simple and complex systems.” See http://arxiv.org/abs/1312.4455
Want more Seth Lloyd?
His seminal work in the area of quantum simulation confirmed Feynman’s hypothesis that a universal quantum computer was possible. Famously Lloyd demonstrated limits on the amount of computation that can be performed within a given volume of space time. See http://arxiv.org/pdf/quant-ph/9908043.pdf
His paper on Simulation of Many-Body Fermi Systems shows that universe can not be a program on a conventional digital computer since simulation of simple physical systems is intractable. See http://arxiv.org/pdf/quant-ph/9703054.pdf