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Audio Software icon An illustration of a 3. Software Images icon An illustration of two photographs. These classical objects are decoherent and do not display quantum superposition or interference. The classical world grows out of the quantum world. It is not separate from it. Ball devotes a couple of chapters to quantum computing. The increased speed of quantum computers is commonly ascribed to superposition, accessing more than one state of each qubit.
For this the qubits must maintain coherence and not get entangled with their environment. This is a technological challenge, and so far quantum computers have only been able to maintain a small number of qubits in their quantum state for long enough to perform calculations.
So it may be a while before quantum computers challenge conventional ones. Ball sees quantum computers as having excellent potential for specific tasks such as factoring large numbers, important to cryptography, and also for large data base searches.
He doubts that they will replace your laptop for everyday tasks. He also points out that there are skeptics of the idea that quantum computers achieve their speed through parallel processing due to superposition of the qubits. Rather the increased performance may be due to qubits entangled with each other allowing them to be managed together rather than in separate steps saving time.
There are other theories, but no consensus. Copenhagen is his starting point. He shows great respect for Bohr and much of what he said, but takes exception to the notion that there will never be a way to find out more about the quantum world.
He thinks the theories are important even if they are wrong. They may help find a better path to understanding the quantum by spawning new ideas. He devotes a chapter to Many Worlds which he rejects, not because its implications are bizarre, but because he finds it incoherent.
A good end to this discussion is a parlor game Ball cites. In the normal version the questioner has twenty questions which can only be answered yes or no to discover a word, person or thing the other players have agreed on.
Rather they agree only to answer questions in a manner consistent with all the previous answers in a way that allows the discovery of something. At the end whatever answer the questioner comes up with is right as long as it is consistent with those answers.
It sounds a lot like our investigation of the quantum world. The questions you ask determine what you will find. View all 16 comments. In Beyond Weird, Philip Ball argues that we are undermining and oversimplifying quantum mechanics by calling it weird. Quantum mechanics is much more than that and it is a disservice to just use such a common and easy way to describe it, for want of better wording. The problem is that we might not have the right words to describe quantum mechanics.
Quantum mechanics is famous for being ambiguous. The act of measurement plays a central role in its interpretation. Why is quantum theory probabilistic? What about its lack of causality? And do quantum objects have real properties, just like the ones we see in our classical world, the so-called hidden variables of quantum mechanics, or is the measurement act just a way of getting more knowledge and does it present a limit to our knowledge, represented by the collapse of the wavefunction?
Is there some underlying meaning or must we just accept that quantum mechanics is different from any other scientific theory and stop questioning its reality?
These and many others were central themes in the arguments that Bohr, Einstein and other physicists had in the past and still have to this day. These two ways of looking at quantum theory represent the ontic and epistemic views, respectively, which remain a debate to this day among physicists.
Philip Ball gives subtle hints of his stance on the meaning of quantum mechanics throughout the book. In the last chapters this subtlety slowly disappears, as his opinions get more fleshed out.
He seems to be a big fan of the role information its meaning in physics is described in the book could play in quantum theory and also in quantum computing. This a remarkable book about the foundations of quantum mechanics. Anyone from a physicist to a layperson should enjoy it. Philip Ball is a great science writer. Personally, I loved this book with its complete focus on science and would recommend it to anyone interested in knowing why quantum mechanics is indeed beyond weird.
View all 4 comments. Mar 15, Bradley rated it it was amazing Shelves: shelf , non-fiction , reality-bending , science. I always try to get alternate viewpoints from as many scientists as I can.
I also enjoy sorting out my understanding of quantum physics, searching for better stories, better analogies, and just It may not be as charming as some and I don't mind how it skimps on biographies and jumps right into the SCIENCE, but it does fall short in outright describing the math.
That may be a good thing for some. Especially if you're not in the mood to crunch math. To b I always try to get alternate viewpoints from as many scientists as I can. To be certain, this text goes beyond the everyday norm and focuses on the science.
The ideas. The concerns. And it's all in the service of demystifying it all. Quantum Physics is one of those subjects that agrees on fundamental maths but invites wildly divergent theories that make a coherent STORY of our reality. You know: Copenhagen don't go nuts on us, Everett multiple-worlds , String, and more.
What we have in this book is not a biography of the physicists but an admirable attempt to make the famously weird thank you Feynman! I mean, we're human, and humans are most famous for turning all things truly fantastic into the stunningly banal. Step by step, it demystifies the very small particles, removes the term spooky action, and naturalizes all things entangled. It gives time to the various big-action theories that align the quantum with the macro, and all of this is pretty good if not as good as some other books that cover these topics, but what this book does best is describe the current technology of quantum computers.
It doesn't shirk the shortcomings of our descriptions or the limitations of the process. This isn't a PR job by prospective companies trying to sell you a k computer. Some developers are working on cheaper versions. What are they really good at? Factoring prime numbers.
Thank goodness! That's great for all you hackers out there! View all 6 comments. But it's getting closer -- and there's hope, says Philip Ball. Ball has written about as good a popular introduction to QM as anyone could, perhaps because he got his start as a chemist, as did I. And Ball's book has gotten many, many favorable reviews. So, why did it take me 5 months to finish this short book?
Not exactly a gripping read! But every other pop-science explanation of QM I've tried to read has been worse. Some a LOT worse. This is likely the best to date. It still has problems -- as the author freely admits. Citing something close to Rutherford's Rule, above. I particularly like Ball's observation that recapitulating the history of the discovery of QM, as is often done in physics classes, is misleading.
And that "quanta" are more a symptom than a cause. Quanta were "the telltale clue and no more. I just came to "photosynthesis" in my notes, as a good example Ball and others cite as an example of QM effects in everyday life.
I wrote: Grass is green. Nature is grainy. Leave it at that. OK, that's a bit cryptic Just like this topic! And photosynthesis is, well, really hard to understand. I've tried All particles exhibit a wave nature. All waves such as light exhibit a particulate nature such as photons. Hey, Einstein struggled with this stuff, too!
And it is truly a weird result. As you may recall from school. Ball certainly could have made his book more useful as a reference by adding a TOC [!!
Oh, well. I still plan to reread it sometime -- unless something better comes along. Especially if it passes the Rutherford Test! As did other Famous Physicists, including Einstein! The specific review that brought me to read this book was Brian Clegg's at Physics World. Clegg's review is linked there. View all 12 comments. Nov 17, Paul Ataua rated it really liked it. It covers, among other things, uncertainty, entanglement, superposition, non- locality, measurement, and contextuality.
It also explores the major different interpretations and the issues presently being discussed in the field. The whole thing is presented in broad strokes, which actually suited the lacking in a science background me down to the ground. Worth reading if you are interested in the subject.
Beyond whatever subject I end up being interested in from time to time, quantum mechanics, the study of the processes that lie at the bottom of reality, is the most interesting subject. If you disagree, you can physically fight me. I tend to come back to books on quantum mechanics from time to time to learn about the recent discoveries, which in a field as bizarre as this one could mean a complete reframing of reality.
This is the kind of book on quantum mechanics you read after you've been hit w Beyond whatever subject I end up being interested in from time to time, quantum mechanics, the study of the processes that lie at the bottom of reality, is the most interesting subject. This is the kind of book on quantum mechanics you read after you've been hit with most of its mysteries and you have had some time to ponder them.
In any case, the nonsensical results of the famous double slit experiment are a good first approximation to the subject, or to get a refresher. In the double slit experiment, you put a photon gun on one side of a table, a panel in the middle that you can slide revealing either one or two slits, and on the opposite side of the table some sort of "wall" of material that can capture the impression of the photons as they hit it.
The experiment progressed in phases through the years: 1 In a single slit configuration, you shoot a bunch of photons at once. On the wall a stripe appears where the photons hit it: the kind of impression produced when a bunch of particles go through a narrow slit behaving like microscopic bullets.
That's not what happens. Instead you get something like this on the wall: That's an interference pattern caused by waves, which is routinely described mathematically. So are particles concrete entities, or are they waves? Naturally, the photon then would have to pass through one slit or the other, and the final impression on the wall would suggest a particle based nature for the photons.
However, that's not what happens: you get the same interference pattern as in the previous point. But a single photon could not interfere with any other, so that must at least mean that it is interfering with itself. In a two slit configuration and with the photon gun shooting plenty at once, as long as there is a detector in any of the slits that doesn't otherwise interact with the photon, what you get on the wall is a particle based behavior: two stripes of impressions.
The result changes depending on whether or not you choose to measure the progress midway through. That's a phenomenon unheard of in classical physics, not to mention completely illogical.
A photon would hit it and through the detector you would figure out if it passed through that slit or the other. However, nature would not be tricked: if you try to detect the path of a particle from its origin to the moment it hits the wall, the interference pattern disappears. That would mean that a particle that hits a detector after it passes a slit is able to go back in time or know ahead of time that its properties are going to be measured midway through, and the particle will change how it manifests.
The study of quantum mechanics, even at the level of a layman, implies realizing that the most basic assumptions about reality hold up during your day to day just because that's how the world happens to manifest as at your size. But it's quantum mechanics all the way down, and at some point the following assumptions break down: that there's a history of cause and effect you can follow, that an object has a solid physical presence with defined properties, that the properties of an object will not change depending on how you look at it, that all the properties of an object will be located in that object, and not, lets say, light years away, that measuring the properties of an object repeatedly doesn't change the results or even invalidate some property, etc.
The revelations of quantum mechanics strike us as illogical and contrary to common sense, but only because our instincts and intelligence are not attuned to reality as it is: we evolved to handle the world from the ground to the height of some lowest branches, and that's all we ever needed. It's so bad that even putting the behaviors discovered through quantum mechanics in words in a coherent manner is very hard, because it hits the limits of what human language is able to express.
Although quantum mechanics is a field that started in the early 20th century, there's still no orthodoxy about some of its biggest mysteries: turns out that at the bottom of reality everything comes down to something called a wavefunction, a mathematical representation of the probabilities a quantum object's properties will have this or that value when measured.
For example, an electron "trapped" in a box, when measured could have a 95 percent probability of being found inside the solid box, but a non-negligible probability of being found inside the walls of the box, or even outside of it.
The controversy regarding wavefunctions comes down to two factions: one of them believes that the wavefunction relates to an underlying physical reality with a history of cause and effect, but the other position, so far backed by more evidence, says that asking what exists "under" the wavefunction doesn't make sense, because the properties of a quantum object manifest when measured: literally come into existence.
The phenomenon of radioactivity is evidence for this position, because radioactive decay seems to be truly random. Probably my favorite quantum behavior is that of entanglement: two quantum objects can be "interlinked" so as to the properties of one become part of the other. If an entangled electron spins, you know that its paired electron will have spun in the opposite direction. That's how reality works.
The astonishing issue is that the linked effect will happen immediately, no matter how far away one quantum object is from the other, even light years away. This happens with no apparent physical connection of any kind transmiting information between them. Obviously the phenomenon breaks the speed of light, which should be impossible.
It suggests that the distances in spacetime are illusory, and that all the points are in fact connected. That's some hope for someone like me who wishes we would be able to "move" faster than light to other planets. However, some scientists seem to believe that in fact the effects of entanglement don't break the speed of light, because the correlation between the measurement of one of the pairs and the other, to make sure that they have changed, will always be made at the speed of light.
I'm not sure if I can understand that; it seems to me that the effect would have happened anyway already, but part of quantum mechanics is that the effects don't "pop up" into existence until measured. So it's another head spin. Learning about behaviors like these makes many students of quantum mechanics shiver with the notion that reality is in fact a computer simulation likely in a quantum computer.
Anyone who programs complicated graphic simulations knows that only what's going to appear on the screen therefore to be looked at is really represented and drawn, and everything else is just variables waiting to be transformed into a representation when their turn on the stage comes.
If you were to write a simulation that someone would experience, having all of the entities' properties as a range of probabilities to be spawned when someone would require that experience is likely the least resource intensive way of simulating an entire universe, because the underlying memory wouldn't have to keep precise track of anything nobody is paying attention to.
That's very suspicious. So is entanglement in that case: how you would store the coordinates of the entire universe would have no relation to its physical representation, and therefore there would be no problem with manipulating linked entities at the same time. The notion that depending on how you choose to observe nature at its rawest you get different results, often even contradictory, and therefore consciousness seemed to be able to change reality, has seeped over the decades into the public perception, in nasty ways.
One of the worst recent examples is an idea I won't name that seemed to become most popular amongst isolated housewives: that what the universe creates depends on your thoughts, which often means that positive thoughts result in the universe gifting you whatever you wished for and if your kid ended up developing an aggressive cancer, you weren't positive enough.
However, over the recent decades the role of consciousness has been taken out of the picture entirely, and we now understand how a quantum system becomes "classical". A quantum system starts "coherent", with all its possible states in superpositions, but through interactions with the environment, the system "decoheres".
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