Programming the Universe: A Quantum Computer Scientist Takes on the Cosmos (英語) ペーパーバック – 2007/3/13
Kindle 端末は必要ありません。無料 Kindle アプリのいずれかをダウンロードすると、スマートフォン、タブレットPCで Kindle 本をお読みいただけます。
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.
“Lloyd is one of the gurus of quantum and information theory, and in this accessible book he presents an insightful new perspective on the cosmos.”—Sir Martin Rees, University of Cambridge“What an astonishing book! Lloyd is at the forefront of a revolution.” —Kevin Kelly, Editor-at-Large, Wired“Lloyd thinks he has found a new way to explain one of the most basic questions in science: Why is the world so complex? . . . Fascinating and profoundly comforting. . . . Seth Lloyd certainly gives his readers a lot of bang for their buck.”—The New York Times Book Review"Renowned for his innovative conflation of pure physics and computation, Lloyd is well positioned to hack his way into space-time and come back with answers." —Seed商品の説明をすべて表示する
Amazon.com で最も参考になったカスタマーレビュー (beta) （「Early Reviewer Program」のレビューが含まれている場合があります）
Black holes acting as incredibly accurate quantum computers? That's just a start. How about the universe itself being a computer?
This is the intriguing assertion of Seth Lloyd in his new book, Programming the Universe: A Quantum Computer Scientist Takes On the Cosmos.
"The Universe is a quantum computer. ...What does the universe compute? It computes itself. The universe computes its own behavior. As soon as the universe began, it began computing."
The idea, in various forms, has been around for awhile. Ed Fredkin has been developing the idea since the 60's. Though his website is a bit technical for the average reader, a superb article by Robert Wright in The Atlantic Monthly captures both the essential ideas and the man himself.
According to his theory of digital physics, information is more fundamental than matter and energy. He believes that atoms, electrons, and quarks consist ultimately of bits--binary units of information, like those that are the currency of computation in a personal computer or a pocket calculator. And he believes that the behavior of those bits, and thus of the entire universe, is governed by a single programming rule. This rule, Fredkin says, is something fairly simple, something vastly less arcane than the mathematical constructs that conventional physicists use to explain the dynamics of physical reality. Yet through ceaseless repetition--by tirelessly taking information it has just transformed and transforming it further--it has generated pervasive complexity. Fredkin calls this rule, with discernible reverence, "the cause and prime mover of everything."
This "prime mover of everything" is a class of computer programs known as cellular automata which were invented by John von Neumann in the 1950s. More recently Stephen Wolfram has explored cellular automata in great detail in his monumental work, A New Kind of Science, in which he sees this form of analysis and understanding as ushering in a new method of doing science. The cellular automaton is a lattice of cells, which can have a finite number of states. These states result from rules which advance in discrete steps and which simultaneously update the lattice. Wolfram explored hundreds of these rules through computer analysis.
So the universe could itself be a process of working out these computational processes according to some rule. And if so, then our picture of the nature of reality changes dramatically:
Fredkin believes that automata will more faithfully mirror reality as they are applied to its more fundamental levels and the rules needed to model the motion of molecules, atoms, electrons, and quarks are uncovered. And he believes that at the most fundamental level (whatever that turns out to be) the automaton will describe the physical world with perfect precision, because at that level the universe is a cellular automaton, in three dimensions--a crystalline lattice of interacting logic units, each one "deciding" zillions of times per second whether it will be off or on at the next point in time. The information thus produced, Fredkin says, is the fabric of reality, the stuff of which matter and energy are made. An electron, in Fredkin's universe, is nothing more than a pattern of information, and an orbiting electron is nothing more than that pattern moving.
This universe is no longer the continuous process that our perceptual system sees. Rather it is a discrete process of events. The physicist John Wheeler entitled an article on this understanding as "It from Bit"-a phrase that has become a popular way of encapsulating the idea.
Back to Seth Lloyd. He is working at this interface of computer science and physics-- what Robert Wright calls the "twilight zone of modern science". He surveys the basic
principles of quantum computing, exploring questions such as: How much information is there in the universe? How much was present at the Big Bang? Can we re-create it on a giant quantum computer? How is information related to entropy? He answers these questions with surprising clarity for ideas that are so foreign to our everyday understanding.
The strength in Lloyd's book is the presentation of the core ideas of quantum computing. Those of a more philosophical bent might have wished for more speculation on the implications of his model. However, he does end his book with a "Personal Note: The Consolation of Information," in which he describes the tragic death of his teacher and friend Heinz Pagels. They were hiking together in the Colorado mountains when Heinz slipped and fell. After the rescue efforts, he was left with trying to make sense of what happened. He concludes his book with this reflection:
Heinz's body and brain are gone. The information his cells processed is wrapped up in the Earth's slow process. He has lost consciousness, thought, and action. But we have not entirely lost him. While he lived, Heinz programmed his own piece of the universe. The resulting computation unfolds in us and around us: the vivid thoughts and outrageous behavior he impressed on us still flourish in our thoughts and behavior and have their own vivid and outrageous consequences. Heinz's piece of the universal computation goes on.
But there's the main thesis of the book: at least since the Greeks there have been two major propositions for what we may call "the principles" of the Universe: on the one hand Mathematics (Pythagoras, Plato) or the more popular dualistic notion of "form" and "stuff" (or matter) as given by Aristotle. The current statement of this dilemma is wonderfully expressed by John Archibald Wheeler's "It from bit". And like before the bet is set by those who lean to one or the other side, i.e to the "it" side or the "bit" side. I think that the beauty, the Occam's razor simplicity of this book in dealing with the fundamental concepts (the laws) of physics is a clear sign that the "bit" party has the advantage now. So, really, we might be ready for a new change of paradigm that will be significant for new development, not only of physics, but of our knowldege of reality as a whole.
As for myself, I've just ordered "Quantum Computing and Quantum Information", the basic text by Nielsen and Chuang. And also "Quantum Aspects of Life" by Abbott, Davies and Pati. This is the "new way" now to explore ...
- 洋書 > Professional & Technical > Professional Science > Astronomy > Astrophysics & Space Science
- 洋書 > Professional & Technical > Professional Science > Astronomy > Cosmology
- 洋書 > Professional & Technical > Professional Science > Physics > Quantum Theory
- 洋書 > Science > Physics > Astrophysics
- 洋書 > Science > Physics > Cosmology
- 洋書 > Science > Physics > Quantum Theory