Product Description
Is the universe actually a giant quantum computer? According to Seth Lloyd, the answer is yes.

All interactions between particles in the universe, Lloyd explains, convey not only energy but also information–in other words, particles not only collide, they compute. What is the entire universe computing, ultimately? “Its own dynamical evolution,” he says. “As the computation proceeds, reality unfolds.” Programming the Universe, a wonderfully accessible book, presents an original and compelling vision of reality, revealing our world in an entirely new light.

CUSTOMER REVIEWS (Average Customer Rating: 4.0 based on 33 reviews)

An "informational? perspective of the universe

Dr. Lloyd, Gives a convincing argument of how the universe can be perceived as a huge quantum computer. He also gives an understandable explanation of information theory and how it relates to quantum theory and cosmology. He makes a valiant attempt to unify quantum theory with gravity.
August 16, 2008

Living and Computing in Lloyd's Universe

This is a thought-provoking book which explains why we should envision the universe as a quantum computer and how doing so may illuminate our understanding of some difficult questions. In addition it offers a useful summary of quantum computing for the general reader, along with discussions of cosmology, thermodynamics and introductory quantum mechanics (all with a computing "gloss").

As a layperson who had read explanatory books and articles about quantum physics for many years before I ever heard about quantum computers, the first theme the book hammered home for me was that quantum computing in an important sense just is quantum physics. A classical computer can be instantiated in a variety of physical set-ups; a quantum computer is itself a quantum system. While you can try to model a quantum system on a classical computer, you will quickly overwhelm its computational resources. So, quantum computing, in addition to its potential for practical acceleration of computing power generally, gives us a useful and appropriate logical framework to analyze the physics of our world.

The next step for Lloyd is to explore the implications of the ability to perform this kind of "quantum simulation". After describing how the simulation process would work, he makes the conceptual case that, logically, there is no reason to distinguish between what's happening in the simulation and the original system.

Now, the step which motivates the book title: while we can't do it yet, in principle the universe (the accessible part, anyway) is finite in extent, and hypothetically could be simulated in a quantum computer. But, following the point above, since the computer has the same number of qubits as the universe, and since the operations on the qubits simulate the universe's dynamics, we can say that at the end of the day the universe can be thought of as performing a quantum computation.

So what does it mean? What can this view do for us? I think there are two possible answers, one concrete and one more intangible. First, ideas from quantum computing may help in the quest for a theory of quantum gravity. Second, it may offer an improved paradigm for interpreting and understanding the physical world. These ideas are furthre explored in the book.

April 25, 2008

It says quantum so it must be clever

The author says that the universe is a computer because it manipulates matter in an automatic, unthinking way - just like a computer.
But surely this is a circular argument? As the computer works by using the laws of physics, it is a truism to say that the laws of physics themselves constitute a computation. What does this statement actually tell us?
I was hoping that the book would put some flesh on the author's idea, but after reading it I'm still waiting.
At any point in the history of humanity, we have used our most sophisticated knowledge for explanatory purposes. When the most sophisticated machine was a clock, we described the universe as a clockwork machine. Now that the cleverest thing we know is quantum theory, we get books like this.

March 25, 2008

Caught in the middle - too simplistic if you know, too complicated if you don't

I am not a physicist or mathemetician, but I take a great interest in information theory, infophysics, quantum computing etc. There are several books on the subject - some distiliations by journalist/authors, others are books for the layperson written by authorities (Lloyd, Deutsch)

This book takes a more physics-oriented apporach to the issue of universal quantum computing, and omits a fair amount of detail about computation itself. This book is not for peer consumption, but rather for the general public. It is an idea to which I subscribe, given what little I know.

If you want more details, read Deutsch, or various websites on quantum computing (www.qubit.org). This is a vast, technical area of science that cuts across almost all disciplines. The implications of a working quantum computer are staggering, as are its implications with respect to time and time travel.

My only gripe with this book is Lloyd's own self promotion and friendly attempts to poke holes in Deutsch's ideas of the multi-verse. I am not interested in academic ego contests - save them for the conferences. State your case, offer some unamed alternatives, and write up a good bibliography. Thats all I ask!
January 19, 2008

interesting view of the universe

Seth does a fine job of explaining the quantum theory of how the universe works. Easy to understand and an interesting read.
January 07, 2008

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