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Taking a byte out of the universe
BOOKS & ARTS
Taking a byte out of the universe This book claims the universe is a computer. That is not metaphor, it’s hard science, says Seth Lloyd that operate using quantum bits (or qubits), such as those stored on individual electrons, inherit this weirdness: bits can read 0 and 1 simultaneously, and quantum computers can solve problems classical computers cannot. Over the last two decades, a flourishing field of quantum information and computation has generated a wealth of experimental and theoretical tests of information processing at the quantum scale. Vedral is one of the luminaries in this field. In Decoding Reality, Vedral argues that we should regard the entire universe as a gigantic quantum computer. Wacky as
Decoding Reality: The universe as quantum information by Vlatko Vedral, Oxford University Press, $29.95
46 | NewScientist | 20 March 2010
If reality is made of information, then the universe is computing the world
WARNER BROS/BFI
WHAT is the universe made of? Matter or energy? Particles or strings? According to physicist Vlatko Vedral’s appealing new book, it is made, at bottom, of information. In other words, if you break the universe into smaller and smaller pieces, the smallest pieces are, in fact, bits. With this theme in mind, Vedral embarks on an exuberant romp through physics, biology, philosophy, religion and even personal finance. By turns irreverent, erudite and funny, Decoding Reality is – by the standard of books that require their readers to know what a logarithm is – a ripping good read. A bit is the tiniest unit of information. It represents the distinction between two possibilities: yes or no, true or false, zero or one. The word “bit” also refers to the physical system representing that information: in your computer’s hard drive, for example, a bit is registered by a minuscule magnet whose north pole can point up or down. Any system that has two distinct states can act as a bit – even an individual elementary particle: “electron over here” represents zero, “electron over there” represents one. When the electron goes from here to there, the bit flips. At this smallest of scales, however, the universe is governed by the famously weird laws of quantum mechanics. Computers
that may sound, it is backed up by hard science. The laws of physics show that it is not only possible for electrons to store and flip bits: it is mandatory. For more than a decade, quantum-information scientists have been working to determine just how the universe processes information at the most microscopic scale. Starting in 2000, in a series of papers published in Nature, Science and Physical Review Letters, my colleagues and I were able to quantify the exact information processing capacity of the entire universe. Indeed, many of Vedral’s arguments closely, and no doubt unconsciously, follow those of my 2006 book Programming the Universe. Unwitting rediscovery is the
sincerest form of flattery. In general, the parts of Decoding Reality that deal with quantum physics and quantum information are the least original. Moreover, for an expert in the field, Vedral makes inexplicable and significant errors: for example, he misreports by more than 20 orders of magnitude the well-known figure for how many bits of information can be contained in the universe. More rewarding are the sections in which Vedral leaves the confines of his own discipline to speculate and expound on the role of information in biology, finance and philosophy. For example, his exposition of the relationship between computation and genetic information processing in living systems possesses a clarity and elan that rarely appears in scientific writing for a general audience. While it might not make you rich – despite what Vedral coyly suggests – his treatment of the relationship between investment theory and information theory is a pleasure. Finally, Vedral holds out hope for those readers who wish to entertain the notion of a relationship between the paradoxes of quantum mechanics and Vedic philosophy. Not since David Deutsch’s magisterial The Fabric of Reality has a physicist given us such a wide-ranging and intriguing picture of how quantum mechanics constructs the world. ■ Seth Lloyd is director of the W. M. Keck Foundation Center for Extreme Quantum Information Theory at the Massachusetts Institute of Technology and author of Programming the Universe (Knopf Doubleday, 2006)
Taking a byte out of the universe This book claims the universe is a computer. That is not metaphor, it’s hard science, says Seth Lloyd that operate using quantum bits (or qubits), such as those stored on individual electrons, inherit this weirdness: bits can read 0 and 1 simultaneously, and quantum computers can solve problems classical computers cannot. Over the last two decades, a flourishing field of quantum information and computation has generated a wealth of experimental and theoretical tests of information processing at the quantum scale. Vedral is one of the luminaries in this field. In Decoding Reality, Vedral argues that we should regard the entire universe as a gigantic quantum computer. Wacky as
Decoding Reality: The universe as quantum information by Vlatko Vedral, Oxford University Press, $29.95
46 | NewScientist | 20 March 2010
If reality is made of information, then the universe is computing the world
WARNER BROS/BFI
WHAT is the universe made of? Matter or energy? Particles or strings? According to physicist Vlatko Vedral’s appealing new book, it is made, at bottom, of information. In other words, if you break the universe into smaller and smaller pieces, the smallest pieces are, in fact, bits. With this theme in mind, Vedral embarks on an exuberant romp through physics, biology, philosophy, religion and even personal finance. By turns irreverent, erudite and funny, Decoding Reality is – by the standard of books that require their readers to know what a logarithm is – a ripping good read. A bit is the tiniest unit of information. It represents the distinction between two possibilities: yes or no, true or false, zero or one. The word “bit” also refers to the physical system representing that information: in your computer’s hard drive, for example, a bit is registered by a minuscule magnet whose north pole can point up or down. Any system that has two distinct states can act as a bit – even an individual elementary particle: “electron over here” represents zero, “electron over there” represents one. When the electron goes from here to there, the bit flips. At this smallest of scales, however, the universe is governed by the famously weird laws of quantum mechanics. Computers
that may sound, it is backed up by hard science. The laws of physics show that it is not only possible for electrons to store and flip bits: it is mandatory. For more than a decade, quantum-information scientists have been working to determine just how the universe processes information at the most microscopic scale. Starting in 2000, in a series of papers published in Nature, Science and Physical Review Letters, my colleagues and I were able to quantify the exact information processing capacity of the entire universe. Indeed, many of Vedral’s arguments closely, and no doubt unconsciously, follow those of my 2006 book Programming the Universe. Unwitting rediscovery is the
sincerest form of flattery. In general, the parts of Decoding Reality that deal with quantum physics and quantum information are the least original. Moreover, for an expert in the field, Vedral makes inexplicable and significant errors: for example, he misreports by more than 20 orders of magnitude the well-known figure for how many bits of information can be contained in the universe. More rewarding are the sections in which Vedral leaves the confines of his own discipline to speculate and expound on the role of information in biology, finance and philosophy. For example, his exposition of the relationship between computation and genetic information processing in living systems possesses a clarity and elan that rarely appears in scientific writing for a general audience. While it might not make you rich – despite what Vedral coyly suggests – his treatment of the relationship between investment theory and information theory is a pleasure. Finally, Vedral holds out hope for those readers who wish to entertain the notion of a relationship between the paradoxes of quantum mechanics and Vedic philosophy. Not since David Deutsch’s magisterial The Fabric of Reality has a physicist given us such a wide-ranging and intriguing picture of how quantum mechanics constructs the world. ■ Seth Lloyd is director of the W. M. Keck Foundation Center for Extreme Quantum Information Theory at the Massachusetts Institute of Technology and author of Programming the Universe (Knopf Doubleday, 2006)