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Is Quantum Reality Analog after All?
Conventional wisdom says that quantum mechanics is a theory of discreteness, describing a world of irreducible building blocks. It stands to reason that computers—which process information in discrete chunks—should be able to simulate nature fully, at least in principle. But it turns out that certain asymmetries in particle physics cannot be discretized; they are irreducibly continuous. In that case, says David Tong, author of "Is Quantum Reality Analog after All?" in the December 2012 issue of Scientific American, the world can never be fully simulated on a computer.
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20 Comments
Add CommentThis is the question I had fifty years ago when I first heard the proposition that light appears to exist both as waves and particles. I could not fully accept it then and I still cannot now. The condition, as I later found out, is that the change is observed in interaction with matter. Lately, I refined my ideas to suggest that a stream of discrete packets of energy (photons)or interruptions in the continuity of the wave is caused when the wave intersects with the energy of electrons in orbit around a nucleus. The electrons, as we know, gain energy in this interaction and are promoted to larger orbits around the nuclei of their respective atoms. The energy that is absorbed from the intersecting wavefront reduces the constancy needed for continuity and appears as discrete packets to the observer. The exact nature of this interaction should be able to be calculated as a function of the frequency of the waveform and the energy constant of the outer orbitals of the specific elements involved. Under this conjecture, when out of the influence of matter, the wave should reform at the same or at a less energised level of the spectrum (e.g., the same or a different colour), depending on how much energy has been "robbed" from it. Can this be tested?
Reply | Report Abuse | Link to thisNicely put! I think you might find this essay quite interesting: Eric Stanley Reiter, "A Challenge to Quantized Absorption by Experiment and Theory",
Reply | Report Abuse | Link to thishttp://fqxi.org/data/essay-contest-files/Reiter_challenge2.pdf
The title doesn't follow from this evidence. The suggestion is that reality cannot be fully simulated (although if time is not constrained an analog process could be simulated to whatever level of granularity one might choose, *approaching* a simulation, a la digital audio, video, and images) which may in fact be true. It's not the case, however, that one can deduce that one is not a simulation from that information. Human perception is not continuous, and it would still be entirely possible to simulate analog events *to a simulated consciousness*. That is, "Level Of Detail" writ... well, very, very small. Larger processes could be simulated probabilistically/statistically, with precision provided only when a simulated mind was actually interacting with them in some way.
Reply | Report Abuse | Link to thisTwo words: Analog Computer
Reply | Report Abuse | Link to thisThree words again: Asimov Galactic Multivac
More words: Analog-digital hybrid computers
Even more words: Alien Analog-Digital Quantum Hybrid Multiverse Simulator (C) and 12-D printer
The Matrix lives on =)
My point being, YOUR computer may not be able to simulate the Universe, but who says that we, as simulated entities, even have the capability to understand or even imagine the device used to simulate us?
Reply | Report Abuse | Link to thisSorry, the simulation thingy cannot be discarded so easily.
Well, the simulation argument does assume similar universes. It uses our own ability/inability to simulate reality to draw a conclusion about the probability of our own universe being a simulation. It says, essentially, if we can simulate consciousness and an encapsulated reality for that consciousness, and if those simulations become ubiquitous, then its likely that the vast majority of conciousnesses that will ever exist are simulations - therefore, the likelihood is high that *I* am such a simulated consciousness. If we cannot, in fact, simulate our own universe for encapsulated consciousnesses, then the Simulation Argument loses most of its teeth, and the Matrix goes back to being "cool sci-fi" rather than a fairly interesting philosophical argument.
Reply | Report Abuse | Link to thisWell, the simulation argument does assume similar universes. It uses our own ability/inability to simulate reality to draw a conclusion about the probability of our own universe being a simulation. It says, essentially, if we can simulate consciousness and an encapsulated reality for that consciousness, and if those simulations become ubiquitous, then its likely that the vast majority of conciousnesses that will ever exist are simulations - therefore, the likelihood is high that *I* am such a simulated consciousness. If we cannot, in fact, simulate our own universe for encapsulated consciousnesses, then the Simulation Argument loses most of its teeth, and the Matrix goes back to being "cool sci-fi" rather than a fairly interesting philosophical argument.
Reply | Report Abuse | Link to thisI agree with you, in the general sense of the argument. My sarcasm was basically directed at the absoulte tone of the title and, in fact, the article that completely discards the possibility. I think it is still an iteresting (although go-nowhere and improbable anyways) possibility to ruminate when feeling philosophical.
Reply | Report Abuse | Link to thisAs an aside, as VR references go, I'd go with The Thirteenth Floor rather than The Matrix in this case... but that's just me =)
LOL - I liked 'em both. The Thirteenth Floor was a nice take on it as well. I think we agree that the title's complete dismissal was unwarranted :D
Reply | Report Abuse | Link to thisI think that if we discover a means of simulating a universe with encapsulated consciousnesses, the Simulation Argument becomes suddenly compelling. Until that time, it's (as you say) just a fun possibility to consider.
I can't say for sure, but the title may have been specified more by the SA editors than the author. Eye-catching titles that are not particularly well suited to their subjects seem to be a common occurrence in SA.
Reply | Report Abuse | Link to thisYour point of using an analog computer to model continuous processes is an excellent suggestion to particle physicists! It seems the idea of using that more appropriate presumedly superseded technology has not occurred to any of them. Perhaps they are simply too enamored with digital/quantum dogma!
As for the simulation, as I understand it's really just a discussion point - the essay's argument is over whether the universe is digital or analog: specifically whether the continuous process of nuclear decay produced by the weak interaction can be described using only discrete, quantifiable elements.
How comical,doesn't anybody know that if we are in a simalation we can be made to see and think whatever who's running it wants.All our tests and outcomes are part of the program.
Reply | Report Abuse | Link to thisAmong other things, the "disproof" of the universe being a computer simulation is, essentially, jus the readouts of machines. For events at the quantum level, supposedly, there is no direct personal observation. An event occurs, a result develops, the result interacts with a sensor, the sensor delivers information to a measuring device and the measuring device reports what it sees. If the universe was a simulation, being run by advanced beings, there are any of a number of places in the process where erronesou continuous looking information could be inserted! Basically, once constructed, any machine for observation functions like a black box. There is no guarantee that what comes out is always an accurate representation of what was observed. For individual events at the quantum level, for example, it is presumably impossible that they can be observed both by individuals and then by machines. There is no proof that what the machine says it sees is what the observer would see.
Reply | Report Abuse | Link to thisAnd, again, so like the presumption of God creating the universe, yet this is discussed and treated as a legitimate consideration, while, if someone talks about God, so many, if not all, "science" devotees call them insane.
I'm generally not in the habit of staying up late to prove that someone is wrong on the Internet but, besides not really explaining anything clearly, this podcast states something which is just so massively wrong it'd be irresponsible of me not to correct it before Saturn rings of bollocks start to gravitate around it. I'll get right to the point: electrons, quarks, even photons (how quantum mechanics actually started!), do come in lumps, and that does never ever emerge from solving any equation. There is never a quantity in the equations which is a continuous amount of electron. That's just scary wrong. What might be continuous however, is the probability distribution of finding that electron somewhere. The microscopic world has taught us two things: matter and radiation come in lumps and their probability of moving from somewhere to somewhere else follows wavelike laws. What does that mean physically? Well, for example, when the electron is caught in a force field, I will only detect electrons in there with an energy taken from a discrete set of values. If the electron however moves fast enough so that it can altogether escape, the allowed set of energy values will be continuous. One interesting resulting effect is the famous Casimir force. If I take two reflective plates, the particles between them will be distributed in a discrete energy spectrum because they are confined, but the ones outside are allowed to take any energy value. As a result, there is a higher pressure on the outer side of the plates which translates into an attractive force between them.
Reply | Report Abuse | Link to thisI'm not a physicist, but in his FQXi essay contest entry that is the subject of this discussion, the author states at the bottom of page 4:
Reply | Report Abuse | Link to this"Despite what we learn in high school, the basic building blocks of Nature are not discrete particles such as the electron or quark. Instead our fundamental laws of physics describe the behaviour of fields, continuous fluid-like objects spread throughout space. The electric and magnetic fields are familiar examples, but our best description of reality — the Standard Model — adds to these an electron field, a quark field, and several more. The objects that we call fundamental particles are not fundamental. Instead they are ripples of continuous fields, moulded into apparently discrete lumps of energy by the framework of quantum mechanics which, in this context, is called quantum field theory. In this way, the discreteness of the particle emerges. It is conceptually no different from the energy levels of the Hydrogen atom."
Please see David Tong, "Physics and the Integers,"
http://fqxi.org/data/essay-contest-files/Tong_integers.pdf
While for many purposes particles can be considered to be pointlike, I think the author is correct - also see
http://en.wikipedia.org/wiki/Quantum_field_theory
See Young's experiment.
Reply | Report Abuse | Link to thisThere is an experiment underway to test if we can see if we are in a simulation.
Reply | Report Abuse | Link to thisAnd yes if we are in a simulation of sufficient complexity we would not know. And if we did find out they could rewind the clock and change the results....
Yes, that is exactly what i meant by bollocks. That exact sentence. I won't tell you that I actually am a physicist because that really shouldn't affect your opinion. What is meant by an electron field is actually the set of transition amplitudes between states that an electron can take in a given system. That is not as abstract as it sounds. Just as I said before, non-relativistically an electron in a force field can only be in a discrete set of energy states. These states might not be stable, and an electron in one has a probability per time unit of switching to another state. Now the problem in relativistic mechanics, is that electrons in a force field also have a chance of switching to negative energy states which, as mystical as that may sound, represents the annihilation of a positron and an electron. The existence of such a process means that this field of transitions must also include transitions between states of different number of particles, in this case, for example, from two particles to none. But never does anywhere the wave function of a half electron appear anywhere. What's more impressive is that even the electromagnetic interaction between charged particles comes in bits, called photons. The fact is so puzzling that, if I'm not mistaken, Richard Feynman said that if all scientific knowledge should be erased but one thing, that thing should be that everything is made of particles.
Reply | Report Abuse | Link to thisIf the creators of "Matrix reality" are advanced enough to devise such an incredible simulation, couldn't those creators also have devised algorithms that would support the realism of the simulation--including making sure to mask those pesky physics problems that could threaten the believeability of the matrix?
Reply | Report Abuse | Link to thisJust sayin'...
I agree with a lot of the criticisms of this article, including the idea that if our universe is simulated, it is at the level of our perceptions, not at the level of the subatomic particles. We could never know just by looking at our physics experiments whether the universe is simulated or not.
Reply | Report Abuse | Link to thisThere is another way to know, however, and that is by looking to see if the universe makes any "mistakes" that would give itself away. Back when I was a grad student, I and my colleagues noticed many events like this. We just called it "just one of those things," and went on like it was no big deal. In fact, my first encounter with professional science involved just such an event, and the scientist in charge said I was imagining things. After that I started looking for them, and I see that they happen all the time. I started asking other people if they noticed such things, and more than half of the scientists I asked reluctantly admitted that they had.
I think we can tell a lot about how the simulation works by looking at the kind of "mistakes" it makes, and also considering the fact that it does not actually eliminate the "mistake" by rewinding and correcting itself.
I have been putting quotes around the word "mistake" because maybe they are not really mistakes. To me, the fact that we can see them at all means that we are supposed to notice them, and include that in our knowledge of the universe.
I appreciate your perspective and your superior specific knowledge - I am certainly not a physicist. You make a good point - "But never does anywhere the wave function of a half electron appear anywhere," however virtual particles do seem to cross back and forth between the threshold of discrete quantification. I also have to point out that while "even the electromagnetic interaction between charged particles comes in bits, called photons," actually those interactions only terminate in the collapse of a disperse, linearly propagating wave.
Reply | Report Abuse | Link to thisI'm in essence merely an old information systems analyst, but I can refer to an alternative perspective that you might find interesting, as it relates to "But never does anywhere the wave function of a half electron appear anywhere": Eric S. Reiter, (2012), "A Challenge to Quantized Absorption by Experiment and Theory,"
http://fqxi.org/data/essay-contest-files/Reiter_challenge2.pdf