Programming the Universe: A Quantum Computer Scientist Takes on the Cosmos

by Seth Lloyd

Is the universe actually a giant quantum computer? According to Seth Lloyd—Professor of Quantum-Mechanical Engineering at MIT and originator of the first technologically feasible design for a working quantum computer—the answer is yes. This wonderfully accessible book illuminates the professional and personal paths that led him to this remarkable conclusion.

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. And what is the entire universe computing, ultimately? “Its own dynamical evolution,” he says. “As the computation proceeds, reality unfolds.”

To elucidate his theory, Lloyd examines the history of the cosmos, posing questions that in other hands might seem unfathomably How much information is there in the universe? What information existed at the moment of the Big Bang and what happened to it? How do quantum mechanics and chaos theory interact to create our world? Could we attempt to re-create it on a giant quantum computer?

Programming the Universe presents an original and compelling vision of reality, revealing our world in an entirely new light.

Genres: Science, Physics, Nonfiction, Computer Science, Philosophy, Programming, Computers

240 pages, Hardcover

First published January 1, 2006

About the author

Seth Lloyd is a professor of mechanical engineering at the Massachusetts Institute of Technology. He refers to himself as a "quantum mechanic".
His research area is the interplay of information with complex systems, especially quantum systems. He has performed seminal work in the fields of quantum computation and quantum communication, including proposing the first technologically feasible design for a quantum computer, demonstrating the viability of quantum analog computation, proving quantum analogs of Shannon's noisy channel theorem, and designing novel methods for quantum error correction and noise reduction.

read more: http://en.wikipedia.org/wiki/Seth_Lloyd

Reviews

[Nathan Nifong · Rating 1 out of 5]

Programming the Universe was very hard for me to finish. despite how interesting I find information theory, quantum mechanics, and computer science, I just could not tolerate Seth Lloyd's writing. Extracting the underlying concepts from his disorderly descriptions is as tedious a process as getting pure metal from raw ore.

[Zak J]

I have mixed feelings about this book. While the content was often interesting, it was also severely lacking in some places. He would make claims that were pivotal to the book's progression and then leave them unexplained. For instance, he would reach an important conclusion that the entropy of this was lower than that and therefore wasn't a violation of the 2nd Law, but would offer no explanation as to how he arrived at this conclusion. He elaborated the importance, but not the path to the solution. I couldn't decide who the intended audience was. I'm somewhat familiar with the subject, but I was often confused conceptually. If it's for those that are familiar with Information Theory and Physics, it needs more rigor. If it's for the lay-audience, I would guess there's no hope. Perhaps a more accomplished physics student wouldn't need explanation where I did.

[Denis Vasilev · Rating 3 out of 5]

Мозг взрывается, концепции интересные, но понимания от прочтения не прибавляется.

[Geo · Rating 4 out of 5]

So first of all, thanks to Geoff for lending this to me. And no, I don't care that the Mayan 2012 hokey drug book I traded you for it is at the bottom of a ravine in the mountains.

First, a caveat. I am *decidedly* an amateur when it comes to physics, quantum mechanics and similar topics. I am not, however, an amateur when it comes to programming and computer science. It frames the rest of the review, since this book delves pretty darn deep into both fields.

Alright, since I'm on the topic, I suppose I should get to the meat of that. Can someone who is a neophyte when it comes to these two topics enjoy it? The short answer is yes. But, I will say that it helps tremendously to be already well versed on the various topics discussed. That having been said, thinking about the universe, cosmology, programming, information, entropy and various other topics of similar ilk for any length of time is enough to put off the most steadfast of reader. If you're not well versed in these things, I would say that you need to be willing to do some research, talk to other folks that know lots more than you do about such things, and generally use it as a learning tool. If that isn't what you want to spend your time on, you aren't likely to see the back cover of this anytime soon.

Moving on to how "sciency" it is. It is sciency. While there are plenty of funny, emotional and otherwise passionate anecdotes and jokes ... guess what, they're geek jokes. Chances are, you won't get some of them. I know I didn't.

Next, I would say this is a decent mix of the recent state of quantum computing and speculation as to what some of the things that are driving progress in that area might ALSO mean in terms of other deep questions. It even goes so far as to speculate that some of the information theories they're working with now provide the framework for a real Theory of Everything(tm). In the former context, it was a great primer. I wasn't aware of all that has transpired in this field. In the latter, I find it no more or less useful than any of the other theories currently being bandied about about those same questions. In my own mind, it is sort of like flogging Schroedinger's Cat. Flog away. We're not even sure if its alive or dead. Flogging can't hurt, can it?

I found the writing accessible. I am probably not the target audience. Or maybe I am, I don't know. I found some of it quite refreshing. I had never, and probably *would* never have made a connection in my own mind between entropy, information and the actual manner in which quantum computing might work. It did get me thinking some pretty deep thoughts about all of it, I'm quite sure all of which was in the "Intro" section in some quantum computing graduate course, and these guys would laugh at me. (Model Game of Life against qubits? Thats *SOOO* 1999.)

It absolutely served its purpose. I look forward to doing more research on this as time permits (HA!). I would love to talk to this guy sometime over a beer or three. I probably will not go pursue this guy's scientific papers, since ultimately, this isn't my field and won't ever be. But I do like to be able to parlez the lingo, savvy? Plus, chics dig it.

Peace.

[Gorana · Rating 5 out of 5]

I really like Seth Lloyd. There are many extremely smart people today, but only few of them are able to explain and present certain theories so they are comprehensible to other people (especially in QM). So, in a way, Lloyd is like a modern Richard Feynman, also because he is witty, funny and easy to follow. Even though he deals with subjects that are way beyond our everyday experience, and even in that category, are very hard to conceptualize and understand, cause at a time they can be very counterintuitive, he still manages to connect them with things slightly closer to 'our world', so they become more presentable to people who are not so familiar with QM and information theory, and at the same time, offer a new perspective to people who are (and you can never have enough different perspectives of entropy, trust me). So this book is never boring even if you have previously encountered theory of universe as ultimate quantum computer, entropy explained through known and unknown qubits, connection of all of that with ToE...
In certain fields you can never find a middle ground between popular science literature and strictly scientific literature, and as someone who studied CS and will also be studying physics, lately I try to stay away from the first and focus on the second, but nonetheless, I really liked and enjoyed this book.
Also,I used to think I would be willing to give a kidney to be able to attend Lloyd's lectures @ MIT. I was wrong. Now I KNOW I would gladly give both of them.

[Sarah Far · Rating 4 out of 5]

این کتاب نخستین کتاب مرجع فارسی مقدماتی در بحث کامپیوتر کوانتومی است.

رایانش کامپیوتری به دنبال تفسیر و توضیح نمونه در آغاز و انجام عالم هست.که بگوید عالم چیست و چرا هست؟
این کتاب رمان نیست ولی کتاب درسی هم نیست
کتابی برای علاقمندان به فیزیک،کامپیوتر و کیهان هست (و حداقل منو یادِ کتاب جدید دن براون «سرچشمه» میندازه)

[Юра Мельник · Rating 5 out of 5]

Можливо колись значну частину цієї книги відправлять у бібліотеку псевдонаукової писанини, але на сьогодні це збірник найпрогресивніших природничих ідей. Якби у мене спитали, про що ця книга, я б відповів, що вона про квантовий ком’пютер. Дехто може зауважити, що вона розказує про щось більше ніж квантовий комп’ютер, але хіба такі речі існують?

Рекомендовано до прочитання після Короткої історії майже всього на світі Б. Брайсона, Фізики часу Річарда Мюллера і Початку безкінечності Девіда Дойча.

[Ami Iida · Rating 4 out of 5]

This book covers the basics of quantum understanding science.
But explanation of quantum computer is difficult dramatically.
You should be aware of it.

It has described the quantum mechanics from the primary step. it is easy for the beginners to read it.
my recommendation.

chapter 2 ; It is written about a logical game of Wittgenstein. the author is an extensive knowledge.

chapter 2 ; it is written about The principle of the computer. for example Logical gate,etc..........
chapter 3 ; the story of Big Bang. Bang! Bang!Bang! Big Bang LOL

Maxwell's demon appears in chapter 4.
https://en.wikipedia.org/wiki/Maxwell...
maxwell demon experimenthttps://www.youtube.com/watch?v=jB5IJ...

the author's Quantum mechanical interpretation is different from that of other physicists .
So you should not read Quantum mechanics for the first time ...more

[Antonio · Rating 5 out of 5]

The idea of the universe as a computer is not new, of course. Lloyd declares that from the very beginning and continues to explain in some detail several theories that have seen the universe as such a machine. Then, he asserts that in fact the universe is a quantum computer and from there, plenty of new stuff spread over the book. Lloyd describes briefly, but concisely quantum theory and its relevant aspects to create a quantum computer. The final chapter about measuring complexity was particularly interesting.

[Tavo · Rating 2 out of 5]

This book ambitiously sets out to demystify the complexities of quantum computation but ultimately falls short in execution. The author's intent to unpack such a complex topic within the confines of a relatively brief text leads to an experience that oscillates between confusion and clarity. Despite its goals, the book struggles to deliver a coherent narrative, often feeling more like a poor summary version of a far more detailed manuscript.

The presentation of foundational topics such as thermodynamics, information theory, Boolean logic, and particle physics is cursory at best, providing a shaky platform from which Lloyd attempts to launch into deeper explorations. The utilization of images, which could have served as a valuable tool for elucidation, instead adds to the perplexity; repetitive depictions of an atom and its spin do little to enhance the reader's understanding of the material.

Lloyd's prose does not help matters, as it too often veers into self-promotion, detracting from the potential to engage meaningfully with the content. This focus on the author's credentials and prior work adds an unnecessary layer of distraction, further impeding the book's ability to educate and inform.

However, it's not without its merits. The concluding chapters offer intriguing reflections on the intersections between biology, cosmology, computation, and quantum mechanics, highlighted by apt analogies that strive to make the complex concepts of quantum mechanics more accessible. These moments of clarity and insight earn the book a modest recognition.

Ultimately, it deserves a two-star rating, acknowledging the fleeting glimpses of potential amidst a largely frustrating endeavor. The insights into biology and cosmology, coupled with the occasional effective analogy, provide some redemption. Yet, these strengths are insufficient to overcome the book's significant shortcomings, leaving it as a missed opportunity to compellingly convey the wonders of quantum computation to the lay reader.

[Maxwell Dalton · Rating 2 out of 5]

One final review to close out the year. Seeing as it's 8pm on new years, I'll try and keep it relatively concise.

This is, as the title states, a book about quantum computers. Seth Lloyd is a key figure in quantum computers and has been from the outset of the field, and in this slim volume he attempts to guide the general populace through such topics as computer science, quantum mechanics, astrophysics, and the history of the universe.

Needless to say, this is a monumental task to attack without any detailed mathematics, and sadly Lloyd often falls a bit short: I was excessively confused when reading many parts of this book, in particular anything about quantum mechanics itself. I suppose that Lloyd does state, however, that being confused is a good sign that you're understanding quantum mechanics.

The main / most interesting part of this book is Lloyd's definition of the universe as one large quantum computer. This is really just a different way of looking at things, and didn't seem excessively monumental to me, but then again I am not a physicist. Once you've defined a quantum computer as the interplay among quantum particles as Lloyd does, it pretty much directly follows that everything is a quantum computer, unless I am missing something huge here.

But yeah, for me, these books that try to convey something that requires 10+ years of study to the general populace are almost always doomed to fail: they are too dumbed-down to actually explain anything in a satisfactory way, and always leave the reader excessively confused. Couple that with Lloyd's weird rhythms / interjections of personal informations and his pacing, and you're left with a pretty meh book in my opinion.

Nevertheless, I'm still glad I read this book as I feel that I know a little bit more about quantum computers and quantum mechanics in general than before I read it, but I would hardly call this an enjoyable read.

TL;DR: A poorly-written book but with some pretty cool ideas, provided you can understand any of it.

[Bria · Rating 2 out of 5]

Pretty disappointing - I generally like Seth Lloyd but this book was hard to get through. Luckily I slept through most of it while Rob read. Not sure exactly what the problem is - too repetitive? Too simplified? Jokes didn't land? Personal stories uninteresting? I potentially could have learned something when we finally got to the actual quantum universe stuff closer to the end, but by then I was just trying to get it over with.

[Maith · Rating 5 out of 5]

An eye-opening look into quantum mechanics and it's influence over the universe

[Daniel Woodworth · Rating 4 out of 5]

Well written, if a bit obscure at times. Lloyd failed to show me--but then, I am rather dense when it comes to theoretical physics--what, precisely, he meant by "computing," when used with regard to the universe, but the discussion was nevertheless fascinating.

[AmirInt · Rating 5 out of 5]

This book threw me into the world of physics and computers. Coupled with masterly explained material in a way that the reader can go deep through the subjects, the reader finds themselves being levelled up and encouraged to expand their view and get new ideas through this page-turner. Helped me establish a new method of thinking.

[Charles Daney · Rating 3 out of 5]

This short book (about 220 pages) covers a large number of topics: information theory, thermodynamics, complexity, computing, quantum computers, quantum mechanics, the quantum measurement problem, interpretations of quantum mechanics, cosmology, and quantum gravity. Unfortunately, that's too many for such a short book. If one hasn't read separately about each of those topics, the treatment here will provide only a superficial picture. The book was first published in 2006, and there don't seem to have been important new developments in any of the topics since them. What is said seems accurate enough, but there's just too little detail. (One small exception is that the effects of dark energy on the expansion of the universe, known since 1998, are glossed over.)

The main thesis of the book is important, though not new. It's that the universe can usefully be regarded as a computer - a quantum computer - whose function is to compute its own behavior. That's sort of a tautology, like saying that a city (for example) computes how it develops. A lot of the process is the semi-random behavior of smaller parts acting more or less independently. For the thesis to become really interesting, the detailed mechanism of how the computation works needs to be shown.

The author proposes that the universe is, specifically, like a quantum computer - the theoretical mechanism of which has been gradually worked out since the 1980s. That mechanism involves representing data as "qubits" and processing being done with quantum logic "gates". All that has been much better described in other books for a general readership, such as Minds, Machines and Multiverse: The Quest for the Quantum Computer. What needs to be done to support the universe-as-computer thesis is to show how these mechanisms work in the universe as we know it.

The strange ways that quantum mechanics works have been pretty well known for almost 90 years, since the work of Schrödinger, Heisenberg, Born, Dirac, and others. And that is quite sufficient to design working quantum computers. (Actually building such things is much harder.) What is still mysterious is what's going on "under the covers". It could be that the universe uses quantum processes for computing that humans haven't even thought of yet.

But even how the universe might work as a quantum computer of the kind already envisioned isn't explained in the book. It is true that during the first instants after the Big Bang quantum fluctuations in the extremely hot particle soup should be responsible for very small inhomogeneities that over billions of years grew into the stars, galaxies, and galaxy clusters of the present universe. However, what "causes" the quantum fluctuations in the first place is still a mystery. They appear to be essentially random.

There's some speculation in the book that quantum processes may be able to explain how gravity works, and it is gravity (and perhaps dark energy) that has been in control of the universe's evolution for the past 13.7 billion years or so. But to make the connection between quantum mechanics and gravity is to develop a theory of quantum gravity. And even today, 10 years after the book's publication, there's no agreed-upon theory of quantum gravity.

[DJ · Rating 3 out of 5]

I read this book in the midst of a wave of readings on viewing the world as information (cybernetics, thermodynamics, information theory). I can't say it introduced many new concepts to this conversation, but more importantly, Seth Lloyd is a wizard with strange analogies that cast old ideas in new frameworks. Many scientists are so obsessed with the importance of their ideas (read: Stephen Wolfram) that they'd be horrified to toss them around and play with them like a child learning new words. Like Feynman though, Lloyd has avoided building a scientific pillow fort and posting his "no jokes allowed" sign. (And like Feynman, he's probably been mistaken for a baked potato a few times.) I'd like to see him write more, but his papers on arxiv are (in comparison to most physics papers) just as quirky but accessible.

If anything, this book mostly served mostly as reinforcement:
- reinforcement of my appreciation of analogy (both as an indication of understanding and a means for teaching)
- reinforcement of my interest in this line of readings
- reinforcement of my intent to apply for MIT's quantum information summer program for undergraduates (which Seth Lloyd heads)

[Javier Cano]

El libro está muy bueno, es una introducción, mas de divulgación, a la computación cuántica, para esto el autor primero presenta una discución muy interesante sobre qué es la información, pues como teórico de la información considera que una computadora sólo sabe manipular información (bits), argumentando que el universo está formado de información, las partículas son bits y hablar en el lenguaje de los átomos es hablar el lenguaje del úniverso y cómo esto podría servir para hacer cómputo, concluyendo que aún así sería muy caro. Después de esto da una introducción muy ligera sobre la mecánica cuántica, la "rareza" cuántica, el principio de incertidumbre, superposición de estados y tal, para al final describir cómo se puede usar todo esto para construir una computadora cuántica, la cual en muchas tareas sería exponencialmente más rápida que las computadoras "clásicas". Al final, se avienta una discusión filósofica en la que expone diferentes argumentos bajo las cuales el asume que el mismo universo es una computadora cuántica en operación.

Haciendo a un lado los malviajes, es un buen libro de divulgación y me parece muy bueno como introducción al cómputo cuántico.

[Larry · Rating 4 out of 5]

I’ve been reading this book for a while. Non-fiction books except history books) always take me longer, as I like to check the facts, absorb the ideas…yeah, I know, it reminds some of you of schoolwork.

Dr. Lloyd’s book is full of ideas worth absorbing, the main one being that the universe is a continually running quantum computer. His book is an excellent mix of computer science, quantum mechanics and information theory, three subjects that can get quite difficult to explain separately, let alone combined. Dr. Lloyd does an excellent job of laying out the groundwork of past and current science, then using that foundation to theorize his ideas. It is a short (211 pgs, PB) little book that is dense with concepts and ideas.

Longer review here.

[David · Rating 5 out of 5]

I really like the Book. Lloyd presents a very strong case for Universal Quantum Computation as being the main synthesizing method behind reality and Universal evolution. Not only were his ideas clear and concise but they were also well backed up by creditable references and experimental data. Though in the end he falls short of nailing down the last pesky pieces of a holistic model of a true "Theory of Everything," that includes a working model of gravity or an explanation of the initial cause of reality, he still certainly has brought a large and interesting piece of the pie. While String Theory has helped us see just how complex and mysterious the Universe can be, I feel this much simpler pathway to understanding the development of the cosmos may in the end prove to be a much more complete model. I would definitely recommend this book to anyone interested in Cosmology and understanding the nature of existence, it was a very worthwhile read.

[David · Rating 4 out of 5]

Really good book. I thought it was going to be a little thicker to read through, given the subject matter it deals with, you know, "Quantum Computing", way beyond rocket science if you ask me, but in the end it resulted in a very well written and well paced book. It did feature some thick paragraphs here and there, but nothing that a double-read wouldn't solve.

I highly recommend it as it adds a whole new perspective to one's universal view. We might be living inside the ultimate quantum computer and it makes sense once you read this book.

By the way, I don't know why the title for the ebook edition has this looping triple take...

[Matt Belcroft · Rating 2 out of 5]

I enjoyed the first few pages of the book because I was joyfully anticipating learning something totally exotic and cool. Unfortunately I began to lose understanding as the book went on and since everything that went later, built on previous explanations, I felt more and more lost. Lloyd does throw in some interesting stories throughout the book and these did help keep the interest level up somewhat. If you have a basic grounding in atomic physics you should be able to get through the book a lot easier.

[Hollis Fishelson-holstine · Rating 2 out of 5]

Interesting and fascinating ideas about quantum computers - truly 'universal' ideas that are mind-bending. I was intrigued and found it interesting, despite realizing I just didn't 'get' much of it in a deep way and finally decided I'd had enough

[Atti · Rating 5 out of 5]

great book, a must read for anyone passionate about natural science.
Mr Lloyd does a great job at explaining the informational theory of the universe. Its a bit to short for me, I would have loved to read more about this theory and about quantum computing.

[Andrew Young · Rating 1 out of 5]

interesting viewpoint on the universe, but very repetitive.

[Nick · Rating 5 out of 5]

Quantum computing pioneer and MIT professor Seth Lloyd gives theoretical and historical meat to the computational/informational/simulated universe hypothesis I have encountered in pieces from John Wheeler’s intellectual disciples—Nick Bostrom, Paul Davies, Ray Kurzweil, Max Tegmark, and Frank Tipler—but in a systematic way. In Programming the Universe, Lloyd builds on Wheeler’s “it from bit” idea—that physical reality emerges from information—to argue that the universe is a vast quantum computer processing bits and qubits. Written with clarity and enthusiasm, this accessible yet rigorous book brings the computational universe to life for intermediate readers, making complex ideas digestible without sacrificing depth.

The book’s core argument unfolds systematically, with Chapters 2 and 7 standing out as critical pillars. Chapter 2 introduces the concept of a bit short for ‘binary digit’ as the fundamental unit of information—not just zeros and ones, but any distinct alternatives, the ‘difference that makes a difference’, in the words of Gregory Bateson. Lloyd explains how computation, built from Boolean logic gates (and, or, not, copy), underpins everything from classical computers to the universe itself. He touches on the halting problem and self-reference, hinting at the limits of computational systems, which resonates with philosophical questions about free will and probability. Chapter 7, “The Universal Computer,” is the book’s crescendo, where Lloyd argues that a quantum computer could simulate the observable universe on a one-to-one basis and if so then would be indistinguishable from the universe. With 10^92 bits of storage and 10^105 operations per second, the universe’s informational capacity is finite yet staggering, governed by quantum laws that classical computers can only approximate.

Lloyd’s historical detours enrich the narrative. He traces the computational universe idea back to Edward Fredkin and Konrad Zuse in the 1960s, later refined by Stephen Wolfram, while grounding information theory in the work of Maxwell, Boltzmann, Shannon, and Landauer. Chapter 4, for instance, elegantly connects Maxwell’s demon to Landauer’s principle: erasing a bit always transfers information elsewhere, preserving the first law of thermodynamics. Similarly, Chapter 5 demystifies quantum mechanics, emphasizing the probabilistic nature of qubits and the many-histories interpretation (favored by Lloyd over the many-worlds model), which treats unobserved quantum states as abstract possibilities rather than physical realities.

For readers, the book’s strength lies in its accessibility and intellectual ambition. Lloyd distills complex ideas—quantum entanglement, decoherence, algorithmic complexity—without sacrificing rigor, making the computational paradigm feel like a natural successor to the mechanical worldview. His discussion of complexity in Chapter 8 is particularly compelling, showing how simple quantum programs, seeded by fluctuations at the Planck scale, can generate the universe’s intricate structures, from spacetime curvature to biological life. Drawing from futurist Freeman Dyson in the final pages, Lloyd describes how intelligence can persevere even in the midst of cosmic entropy, as energy density decreases but space’s expansion increases available energy, by slowing down processing all the way to the quantum level and increasing storage capacity towards infinity, intelligence literally envelops the universe with finite energy but by operating at the vast scales of Brahmic cosmology.

However, the book’s scope invites critique. Lloyd’s conclusions remain firmly within physics, sidestepping metaphysical implications. For some, like myself, the computational universe hypothesis feels incomplete. The halting problem and Gödel’s incompleteness theorem suggest that self-referential systems cannot fully describe themselves, implying that a complete understanding of the universe might require an external perspective—perhaps a noninterventionist, Laplacean “demon” akin to a deistic god, with enough capacity to simulate the universe but not intervening to disrupt it. Lloyd’s preference for the many-histories interpretation aligns with this, treating unobserved states as abstract rather than material, in line with Plato, but he stops short of exploring such philosophical territory. This restraint, while disciplined, may leave readers yearning for a broader synthesis, especially when contrasted with the speculative multiverses of Deutsch or Tegmark.

Programming the Universe is a must-read for those intrigued by the intersection of physics, computation, and philosophy. Chapters 2 and 7 are essential for grasping the computational universe, but the entire book rewards readers with its historical depth and theoretical clarity. While Lloyd’s vision doesn’t resolve the ultimate questions of existence, it provides a powerful framework for understanding the universe as a symphony of information—a provocative idea that lingers long after the final page.

[Leftjab · Rating 4 out of 5]

After the first few chapters, I felt I had drunk the Kool-Aid and this was one of the most mind-blowing reads I’d stumbled across in a while. Yes- the universe can be boiled down to energy and information. That completely and totally makes sense. Everything happens because of some form of energy – time is a chronicle of all energy in flux. And to decode what type of energy is occurring, then we have information. So being cognizant is similar to decoding quantum messages at all times. Written in a very simplistic, declarative style. I was on board.

Lloyd goes pretty deep into the basics of programming and quantum computers and I have to admit, he lost me. I am not a scientist though I enjoy reading pop science books – way more than I had every thought I would. I don’t quite know when that happened – I looked back through my non-fiction reads of the past 5 years and a large number were science related. Maybe because I’m liking more difficult science fiction, something in me was like, if I want to keep up with some of these writers (Greg Egan, Greg Bear), I better at least grasp some of the concepts with which they are dealing so I can visualize where they are taking me. I’ll freely admit that I am not interested in coding – I might be missing out on a major aspect of life as so much of what we do involves code – it really is the lifeblood of our cybernetic existence (Norbert Wiener!). I was watching maybe the movie Us or Fassbinder’s Lola or maybe Demonlover – something pretty heady and was thinking how the best filmmakers present puzzles for the viewer to decode – so this identifying energy varietals via information (i.e. decoding) I find to be completely true. I am decoding the present tense right now by writing this – which then is being coded and uncoded by the program I am using. I believe all of this to be true – so Lloyd blew my little brain wide open there for a minute.

Maybe I’m a bit lost when we get into the purely theoretical aspects of math and science because to me, if it can’t be observed or if there’s no way to determine if something does exist, my layman’s sensibility wants to go to something that can be proven. And I know, Lloyd and others say it repeatedly – the evidence of quantum existence is there – we just collapse the wave once we start talking about it – there’s no way to directly observe all the possible outcomes because we would need to be able to exist out of time. And no one can do that yet. So Lloyd is pontificating about what a quantum computer could be able to do if we were able to create one powerful enough to be able to decode more than one wave. Or something.

I think I would enjoy Lloyd as a professor.

[V Vijendran · Rating 5 out of 5]

Seth Lloyd paints a clear and concise picture regarding the computational capability and the complexity of our observable universe. For a book of merely 200 pages, Seth effortlessly explains the concepts of Information Theory, Quantum Mechanics, both the Theoretical Model and some of the Physical Realizations of Quantum Computations, and maps them to the entire observable universe. He finally finishes the book by explaining the concept of Computational Complexity and how the logical depth of programs could be modified as the Thermodynamical Depth to quantify the complexity of all physical systems.

One of my favourite explanations that Seth Lloyd provides in this book is regarding the Quantum Algorithms; how quantum algorithms are simply an orchestrated symphony of quantum waves and to acquire any valuable information, each wave in must cancel each other rather than the observer forcing an output. This is grossly overlooked by many scientists who publish scientific papers on quantum algorithms and then claiming that Quantum Computers do not offer any sort of speed up compared the classical counterpart.

Moreover, Seth Lloyd is one of the few Quantum Scientists who believe that the Laws of Gravity or The Theory of Relativity could be derived or found within the frameworks of Quantum Mechanics and Quantum Computation. Instead of striking out an entirely new path like String Theory of Quantum Loop Gravity, Seth goes a step ahead. He skillfully describes how one could go on to model a version of Quantum Computation that could adequately capture the essence of gravity and effectively reproduce its results.

More than the ideas presented in this book, what surprises me is that this book was published in 2006, and Theoretical Physicists and Theoretical Computer Scientists were discussing these issues to as early as the 1980s.

[Justin Harnish · Rating 5 out of 5]

One of the best books on the link between quantum physics, computation, and dynamic systems since Deutsch's "Fabric of Reality!" Lloyd makes a mighty effort to explain the qubit-wise computation happening at the fabric of reality and utilizes these quantum distinctions to arrive at larger systems of computation, thermodynamics, quantum gravity!, and ultimately selection and order. While I got lost in some of the early circuitry descriptions, Lloyd works through them numerous different ways to help the reader get to the basic level of understanding necessary to see how classical and quantum computation differ and how quantum computation can be used to arrive at physical, chemical, and ultimately more complex systems.

Lloyd's circuit diagrams of quantum computation AS quantum gravity and the randomness of qubit flipping AS the "monkeys typing on computers" ultimately being responsible for the instructions that led to the universe we have and the complex nature of the present age of the universe are masterstrokes of explanation and truly place this work as a fundamental read for anyone curious how existence generated the reality we live in.

[Jina · Rating 5 out of 5]

Quantum mechanics is always really weird to think about since it’s literally everywhere, but we just can’t see it. Seth Lloyd is an amazing, scientific author. He approaches this topic with humour and humility in realizing his audience isn’t just other scientists who know what he’s talking about. I really enjoyed reading his book. He was truly fantastic at explaining things. While he seems to go off topic here and there, it’s really just to help his readers gain a better understanding of complexity of what he’s talking about. I finally have a better understanding of how to count in binary because he took a few paragraphs to explain the logic behind it. I’ve heard quantum computers mentioned in many books, but had no idea what they literally were or how they operated. They were alway vaguely mentioned as if the author also had no idea what they were. However, after reading this book, I finally know what their physical form is and, as a result, find myself agreeing with Seth Llyod’s proposed idea that the universe, itself, is a actually quantum computer.