8 ms·

Dumb question: Say I have a wooden stick and I break it in half in less than a second. Assume a computer would need several minutes to simulate everything that

Dumb question: Say I have a wooden stick and I break it in half in less than a second. Assume a computer would need several minutes to simulate everything that would've happened in the stick. I clearly got the output faster than a computer (and with more precision), so does this imply I'm doing anything particularly fascinating? I assume the same scenario is possible to concoct for a quantum computer. I assume it wouldn't be particularly interesting either. So what are the criteria for distinguishing those scenarios from the "interesting" cases? And how do we know which case this one is like?

bawolff 3y ago
If you're in the stick making business and need to know how sticks break, the yes.
deleted 3y ago
[deleted]
knorker 3y ago
If you can control your experiment perfectly, then you don't need the simulation. Now break the wooden stick in half while on the moon. In space. At absolute zero. While under acceleration. While spinning. While bombarding it with 10^100 neutrinos/second. And do it with 100'000 randomized iterations of the wooden fibers.
tedivm 3y ago
I don't think this is a stupid question at all- it actually touches on some pretty interesting topics. The human brain is absolutely fascinating, in particular because it is extremely energy efficient and fast at the tasks it does. The more we learn and understand how the brain is working the more we'll be able to improve a ton of computer science topics, from AI to signals processing and a whole bunch more in between.
jabbany 3y ago
One would be the direction of entropy. Breaking the stick is not "particularly fascinating" because you're going in the direction of increasing entropy. However, _putting it back together_ is. In the simulation it takes no more effort to go one way or the other, while you probably cannot put the stick back together no matter how hard you tried. A quantum question that is "interesting" would also be similar to finding order out of disorder (e.g. factoring).
- glompers 3y ago
  Nice comment
- tedunangst 3y ago
  If I provide two model sticks to a physics simulation, it can work out how to put them back together with no more effort than it took to model the break? Like I can model shooting a cannon ball out of a cannon and it will tell me where it lands. Or I can model a cannon ball sitting on the ground and it will tell me where the cannon was?
  - jabbany 3y ago
    A hypothetical perfect simulation should be able to do it both ways indeed! However, the current consensus take of quantum uncertainty means _if_ such a simulator exists, it cannot be of our universe. Or, more likely, such a perfect simulator does not exist. Of course all of this is about a hypothetical of a hypothetical at this point... (This is the same problem as entropy (our current understanding of it). We know it is increasing one-way w.r.t. time, and we can imagine what it means to "reverse entropy" and that there's nothing really theoretically preventing that, but we can't build an actual machine to do that.)
- dataflow 3y ago
  I really love this comment -- it "feels" like the right criterion -- but I guess I'm wondering what criteria (if any) researchers actually use right now. Do they have any criteria for this?
  - jabbany 3y ago
    I'm not a quantum computing researcher but I have friends who work on it. The way they've described this to me (answering a question around "how does one know what quantum stuff is bs") was that it's largely a set of known "hard" questions where we've empirically found hard for classical computing but we maybe could solve with quantum. In a way it's been described as similar to crypto primitives or P?=NP problems where we don't know for certain why it's harder one way vs the other but it seems to be the case based on our current knowledge. It could possibly (but unlikely) be the case that we eventually find classical solutions that are just as fast. They don't seem worried about this though, since at least research-wise just working with quantum as a new tool to solve problems itself is intellectually interesting (and the "solves classically challenging problems" is a good way to frame the work's potential impact to general audiences). Also, there's other supposed uses of quantum beyond just computing, like for communication etc.
rcme 3y ago
Did you really get the answer faster than a computer?or put another way, what question did you answer? How much force was applied to the stick before it broke? How fast was the stick moving 0.04s after breakage? How much sound was produced? There are thousands of questions you don’t have answers to when you simply break a stick.
- Aperocky 3y ago
  I think that was his exact argument against quantum computing.
  - ImPostingOnHN 3y ago
    seems more like an argument for quantum computing
zdragnar 3y ago
The difference between you breaking a stick and the computer modeling it is that you've measured nothing. You don't know, with any precision, the amount of force you used, the rate the stick broke at, how much mass remains in the two pieces and how much was lost to splintering, etc. In other words, assuming the computer model has sufficiently accurate data as an input, it can produce significantly more refined output than a human can through trial. In fields where human trial is exceptionally inefficient- molecular physics, chemical synthesis design, structural material design, etc- a sufficiently fast computer will allow for faster design iteration and perhaps even development of new processes and materials. More concretely, if you wanted to design a new stick that breaks under exactly the conditions that you intend it to, then you can skip a lot of trial and error if your computer can accurately model the materials you are designing and testing. Think construction, civil engineering, energetic chemistry, biological processes (medicine design) etc.
- deleted 3y ago
  [deleted]
- BasedAnon 3y ago
  Now if we had a way of measuring it, it would be interesting to ask what sort of model of computation we could derive from the breaking of sticks
  - reb 3y ago
    I cannot wait to tell you about the cutting-edge technology my team is developing — it's called the twigchain and it's going to change everything.
- dataflow 3y ago
  > You don't know, with any precision, the amount of force you used, the rate the stick broke at, how much mass remains in the two pieces and how much was lost to splintering, etc. But I can measure those with a ruler and a scale. Both before and after the breakage. Takes a few seconds, and I'd need to do that before punching those numbers into the simulator anyway. And I can be precise with where I apply the force, etc. So I don't see how this gets to the point of the question.
wuubuu 3y ago
Not a dumb question! There is a great video by the mathematician Richard Borcherds on this exact objection to current examples of quantum supremacy. https://www.youtube.com/watch?v=sFhhQRxWTIM https://www.youtube.com/watch?v=sFhhQRxWTIM
- dataflow 3y ago
  I love this video, thanks for sharing it. I'm watching it right now and I think I'm going to refer to his "teapot supremacy" from now on.
  - AlexCoventry 3y ago
    I declare AlexCoventry supremacy. No one can compute AlexCoventry better than I can. :-)
    - pieter_mj 3y ago
      Wait until you see a GTP5 simulation of yourself.
  - tsimionescu 3y ago
    There is also an interesting response to that video from a leading quantum computer scientist, Scott Aaronson: https://scottaaronson.blog/?p=5460 https://scottaaronson.blog/?p=5460 He actually goes into significant details about your exact question and proposes some resolutions. It's quite long and I don't think I can do it justice in a TLDR so leaving the link to speak for itself.
    - dataflow 3y ago
      Thanks for the link! I'll take a look. Edit: I just read it and I don't feel like he really answered the question. He had a rebuttal about being able to freely specify parameters, but then his Facebook friend addressed his rebuttal, to which he replies "this is indeed more interesting"... which, well, it certainly is, and also doesn't answer the question! (Well, I guess he also mentions we should expect speedup greater than Avogadro's number, which seems fair, but clearly that's not the bar anyone is claiming to meet, so it doesn't get us anywhere.)
avidphantasm 3y ago
Regardless of how good our classical or quantum computers get, simulating “complex” natural systems is ultimately limited by our ability to observe and measure the physical properties of the “components” (I put quotes here to acknowledge the difficulty/impossibility of delineating system components) of that system. I’m not sure quantum computers will help with that.
- sfpotter 3y ago
  You're missing the point of the question.
  - avidphantasm 3y ago
    I’m saying that for some problems, neither classical nor quantum computers may arrive at an acceptable answer.
CrampusDestrus 3y ago
When you break a stick you just break a stick. When you simulate breaking a stick you know everything about the broken stick. What if you broke the stick to study its material properties? Then you would need to spend months carefully taking samples and measuring all the broken spots. With a perfect simulation? You're done the moment it ends. All the data is there available with a copy paste
- hutzlibu 3y ago
  "With a perfect simulation? You're done the moment it ends. All the data is there available with a copy paste" As far as I understand, to perfectly simulate reality, you would need a second reality.
  - wholinator2 3y ago
    Well of course the simulation is a simulation. They are speaking of the ideal case. A real simulation is an application of a model, the physics of the molecules and structures interacting. They are saying that in the ideal case, once the simulation is complete you have complete knowledge of the entire system at every moment in time. Of course there's a resolution to all this. The time steps are comparatively large to the planck time and the wave functions are approximations, everything is an approximation, that's what makes it a simulation. But the principle is that within your model, once the simulation is complete you know _everything_. You have measured every aspect of reality possible from your simplified version. If your model was arbitrarily close to reality you really would know everything
mistermann 3y ago
I wouldn't think so in the case of a stick breaking, but if you consider a more realistic scenario like running a risk analysis across a hyperdimensional problem space, there is certainly something extremely interesting going on there.
D4ckard 3y ago
You are right, basically anything can be viewed as a computation. Ray Kurzweil discusses this extensively in his book The Singularity is Near, building upon previous work by Edward Fredkin. > To appreciate the feasibility of computing with no energy and no heat, consider the computation that takes place in an ordinary rock. Although it may appear that nothing much is going on inside a rock, the approximately 1025 (ten trillion trillion) atoms in a kilogram of matter are actually extremely active. Despite the apparent solidity of the object, the atoms are all in motion, sharing electrons back and forth, changing particle spins, and generating rapidly moving electromagnetic fields. All of this activity represents computation, even if not very meaningfully organized. (From The Singularity is Near Chapter 3, The Limits of Computation)
Strilanc 3y ago
The key detail you're missing is that the problem must be written down. All details must be specified, so that you can unambiguously tell how well it's being solved. Yes, you can write down a problem inspired by a specific stick. And yes, the written down problem will of course inevitably differ in the details from the real stick. Normally you'd think of these small differences as small errors in the description. But as soon as you try to argue the stick is computing the written-down problem, they become errors in the stick because they affect its ability to implement the problem you wrote down.
carabiner 3y ago
It's like saying you can breathe, yet a computer might take a long time to simulate every chemical process taking place in your body in those 2 seconds of respiration.
jcims 3y ago
I wonder about that frequently. The universe 'executes' physics in, as far as I can tell, a realtime basis (at least within the local reference frame). What is that called as compared to computing a model of the same.
- wanderingstan 3y ago
  Of course for you it feels like realtime, because the physics of “you” are being executed on the same “system”. It’s funny to think that if we are living in a simulation, that the machine we’re running on might have horrible uptime, but we’d never know because our “time” only works when the machine is running!
  - beebeepka 3y ago
    Just like a tick rate in a game
- chaboud 3y ago
  Why do you think time dilation needs to occur in our simulation? Be it from instance-shard transition due to cell crossing (special relativity) or inter-node lag due to spatial density (general relativity), system design constraints dictated the very rules of our “physical” existence. (Poe’s Law notice: yes, I’m joking)
somenameforme 3y ago
Oddly enough, I think this can be answered by headlines alone. Imagine you could do anything remotely interesting with a relative speedup of 47 years to 'instant', where we can say an instant is 1 millisecond. That'd mean in one day of calculation, you could do things that'd take a current era supercomputer more than 4 billion years to achieve. And so on upward from there. Yet we're focusing on this odd and relatively boring metric of 47 years? That suggests that the implications intentionally provoked by the phrasing "Google’s quantum computer instantly makes calculations that take rivals 47 years" are obviously false, even if the statement itself is true in some extremely specific context. So in other words, when genuine quantum progress has been achieved - I don't think we'll need to debate it, as the results would speak for themselves.
Mizoguchi 3y ago
I think a more fair comparison would be that you know how to break the wooden stick so that you end up with one piece measuring exactly 152 mm and you can repeat the feat every single time with other wooden sticks of different dimensions crafted from different trees under different environmental conditions.
robot_no_421 3y ago
You're not modeling or predicting anything though. That's like saying "what if I built a bridge that failed on the first day? A computer would need several days to calculate all the forces that led to the failure, but my bridge failed just fine without any computer help". Well... yes. But try building a bridge that doesn't break. Or to keep with your scenario, try to predict exactly where and how your stick will break before you break it. You can't.
- ori_b 3y ago
  Does Google's implementation of quantum computing help with this sort of scenario, or is it a really fancy way of breaking the bridge?
  - robot_no_421 3y ago
    Yes, and no. Don't ask me rhetorical questions if you don't want a rhetorical answer.
  - __MatrixMan__ 3y ago
    Well you don't have to sacrifice any sticks or bridges to see what happens, so that's a plus. One could imagine stimulating experiments that are implausible to actually perform.
    - ori_b 3y ago
      Yes, but that's nothing new -- we've had computers that were used to solve simulations faster than digital comuters could by setting up electronic (or hydraulic, or pneumatic) parts that simulated the terms of the differential equations: https://en.wikipedia.org/wiki/Analog_computer https://en.wikipedia.org/wiki/Analog_computer Is this quantum computer another iteration on the same concept, or is it solving things that are polynomially harder to simulate classically?
riwsky 3y ago
Your wooden stick is dedicated hardware for computing the behavior of wooden sticks. Fascinating? Pretty subjective—but one of the best concrete proxies we have for "fascination" is "economic value" (cf OpenAI's AGI definition). Is it going to make (or save) you a lot of money to quickly find out how that stick broke? Probably not.
- gnramires 3y ago
  I think you can make the case that, for example, going out, taking a stick from a forest, breaking it and record the sound will be much more economical than trying to simulate a realistic stick breaking sound -- in particular in developer time trying to model sticks and wood breaking sounds in a convincing way (suppose we need say an art asset for a game). It's something complexity theory isn't well prepared to tackle, at least on first look. Complexity theory doesn't take into account the cost of devising an algorithm itself. And complexity theory usually only is interested in asymptotic behavior -- different in both ways from what we have (n=1 and algorithm cost). I think simulations win only when there are significant gains to be had over just doing it in real life, i.e. when you are only interested in a simple aspect that can be summarized by a model, or when for some reason the real life event uses a lot of energy or costs significantly. An extremely accurate simulation of wood and wood breaking, and sound, I think would be quite computationally costly -- the wood is already very complex (not as complex as the base atomic reality -- you probably don't need to model every single atom -- but still very complex). Sticks are cheap, and breaking a stick is easy. Breaking the stick doesn't seem to take much energy, and realistically stick breaking itself (although perhaps not stick collecting) comes out ahead energetically! It gets quite complicated quickly, and it really depends on what you want to model, but I think it's interesting to see when and if simulations are advantageous (for example, you could take the cost of raising a tree into account, or not! is the stick "free" because it would grow and decay anyway?). I think in the long term many things can be simplified into what we're interested, so models increasingly win. But realistically (in our limited lives and limited universes :)) I think there will always be a place for physical experimentation, taking pictures of sticks and recording the sound as they break. (and hopefully our relationship with trees and sticks itself still lasts for a long time...) I say that as someone who really enjoys modelling nature! :) I think modelling and trying to recreate natural process (sometimes with an artistic touch as well) is a great way to understand and appreciate the wonders of the universe. Note: Also, even with ideal reversible 0-cost computation, there's likely to be some kind of polynomial time overhead to 1:1 simulation of reality. This can be enough to justify experimentation instead of simulation, in some cases, when your model itself isn't a significant simplification over reality.
ablatt89 3y ago
Any problems where the configuration space is large, and you want to find some optimal configurations to the problem, would in theory benefit since you can directly map the configurations into the entangled qubits. Entangled qubits give you the ability to physically represent large configuration spaces. The difficult is ensuring entanglement between qubits, scaling up the qubit count, noise reduction between the qubits and the other physical parts of the quantum computer, error correction, and generating the circuit to represent the optimization problem, formalizing a proof that the total time of quantum computation (computation + preparation) is less than to simulate on high performance computers and what not. There's several YouTube videos where some company has mapped their problem into a quantum circuit and claim it provided solutions to optimization problems that they couldn't have found classically but dunno, I guess it would really require AB testing between classically computing it on an HPC versus a quantum computer.
aleksiy123 3y ago
If you need to measure a billion sticks breaking the simulation might start to come out ahead in terms of cost. I think this makes more sense if you use a bridge instead of a stick. Building a full sized bridge to test your idea is prohibitively expensive but a simulation is cheaper to build even if the actually simulation is slower to compute. In real life simulations, small prototypes , and full size prototypes are all useful with various trade-offs of cost and benefits at various stages.
marcosdumay 3y ago
> so does this imply I'm doing anything particularly fascinating If you mean "useful", then I'd like to point our that breaking rods is a common task in many labs all over the world exactly because it can calculate some things better than any non-rod computer we have. If you literally meant "fascinating", then you'd have to ask yourself. For a lot of people, it is.
fnordpiglet 3y ago
The key is things are interesting if they’re interesting to someone. The fact you can break a stick and observe in detail in real time at a minute level better than a computer is very interesting to many people. Botanists, biologists, material scientists, architects, industrial engineers, etc. It’s just not interesting to you. Likewise even contrived quantum experiments like this aren’t interesting to many people. They’re not practical. But they’re profoundly interested to people interested in quantum computing. They’re milestones on a roadmap. There will and are things computer computers won’t do better than classical computers and there are things in reality neither will simulate, and those things are interesting to someone. In fact I think this is a crucial part of basic science- EVERYTHING is interesting. Even the lack of something interesting is certainly interesting to a psychologist :-)

bawolff 3y ago

If you're in the stick making business and need to know how sticks break, the yes.

deleted 3y ago

[deleted]

knorker 3y ago

If you can control your experiment perfectly, then you don't need the simulation. Now break the wooden stick in half while on the moon. In space. At absolute zero. While under acceleration. While spinning. While bombarding it with 10^100 neutrinos/second. And do it with 100'000 randomized iterations of the wooden fibers.

tedivm 3y ago

I don't think this is a stupid question at all- it actually touches on some pretty interesting topics. The human brain is absolutely fascinating, in particular because it is extremely energy efficient and fast at the tasks it does. The more we learn and understand how the brain is working the more we'll be able to improve a ton of computer science topics, from AI to signals processing and a whole bunch more in between.

jabbany 3y ago

One would be the direction of entropy. Breaking the stick is not "particularly fascinating" because you're going in the direction of increasing entropy. However, _putting it back together_ is. In the simulation it takes no more effort to go one way or the other, while you probably cannot put the stick back together no matter how hard you tried. A quantum question that is "interesting" would also be similar to finding order out of disorder (e.g. factoring).

glompers 3y ago
Nice comment
tedunangst 3y ago
If I provide two model sticks to a physics simulation, it can work out how to put them back together with no more effort than it took to model the break? Like I can model shooting a cannon ball out of a cannon and it will tell me where it lands. Or I can model a cannon ball sitting on the ground and it will tell me where the cannon was?
- jabbany 3y ago
  A hypothetical perfect simulation should be able to do it both ways indeed! However, the current consensus take of quantum uncertainty means _if_ such a simulator exists, it cannot be of our universe. Or, more likely, such a perfect simulator does not exist. Of course all of this is about a hypothetical of a hypothetical at this point... (This is the same problem as entropy (our current understanding of it). We know it is increasing one-way w.r.t. time, and we can imagine what it means to "reverse entropy" and that there's nothing really theoretically preventing that, but we can't build an actual machine to do that.)
dataflow 3y ago
I really love this comment -- it "feels" like the right criterion -- but I guess I'm wondering what criteria (if any) researchers actually use right now. Do they have any criteria for this?
- jabbany 3y ago
  I'm not a quantum computing researcher but I have friends who work on it. The way they've described this to me (answering a question around "how does one know what quantum stuff is bs") was that it's largely a set of known "hard" questions where we've empirically found hard for classical computing but we maybe could solve with quantum. In a way it's been described as similar to crypto primitives or P?=NP problems where we don't know for certain why it's harder one way vs the other but it seems to be the case based on our current knowledge. It could possibly (but unlikely) be the case that we eventually find classical solutions that are just as fast. They don't seem worried about this though, since at least research-wise just working with quantum as a new tool to solve problems itself is intellectually interesting (and the "solves classically challenging problems" is a good way to frame the work's potential impact to general audiences). Also, there's other supposed uses of quantum beyond just computing, like for communication etc.

rcme 3y ago

Did you really get the answer faster than a computer?or put another way, what question did you answer? How much force was applied to the stick before it broke? How fast was the stick moving 0.04s after breakage? How much sound was produced? There are thousands of questions you don’t have answers to when you simply break a stick.

Aperocky 3y ago
I think that was his exact argument against quantum computing.
- ImPostingOnHN 3y ago
  seems more like an argument for quantum computing

zdragnar 3y ago

The difference between you breaking a stick and the computer modeling it is that you've measured nothing. You don't know, with any precision, the amount of force you used, the rate the stick broke at, how much mass remains in the two pieces and how much was lost to splintering, etc. In other words, assuming the computer model has sufficiently accurate data as an input, it can produce significantly more refined output than a human can through trial. In fields where human trial is exceptionally inefficient- molecular physics, chemical synthesis design, structural material design, etc- a sufficiently fast computer will allow for faster design iteration and perhaps even development of new processes and materials. More concretely, if you wanted to design a new stick that breaks under exactly the conditions that you intend it to, then you can skip a lot of trial and error if your computer can accurately model the materials you are designing and testing. Think construction, civil engineering, energetic chemistry, biological processes (medicine design) etc.

deleted 3y ago
[deleted]
BasedAnon 3y ago
Now if we had a way of measuring it, it would be interesting to ask what sort of model of computation we could derive from the breaking of sticks
- reb 3y ago
  I cannot wait to tell you about the cutting-edge technology my team is developing — it's called the twigchain and it's going to change everything.
dataflow 3y ago
> You don't know, with any precision, the amount of force you used, the rate the stick broke at, how much mass remains in the two pieces and how much was lost to splintering, etc. But I can measure those with a ruler and a scale. Both before and after the breakage. Takes a few seconds, and I'd need to do that before punching those numbers into the simulator anyway. And I can be precise with where I apply the force, etc. So I don't see how this gets to the point of the question.

wuubuu 3y ago

Not a dumb question! There is a great video by the mathematician Richard Borcherds on this exact objection to current examples of quantum supremacy. https://www.youtube.com/watch?v=sFhhQRxWTIM https://www.youtube.com/watch?v=sFhhQRxWTIM

dataflow 3y ago
I love this video, thanks for sharing it. I'm watching it right now and I think I'm going to refer to his "teapot supremacy" from now on.
- AlexCoventry 3y ago
  I declare AlexCoventry supremacy. No one can compute AlexCoventry better than I can. :-)
  - pieter_mj 3y ago
    Wait until you see a GTP5 simulation of yourself.
- tsimionescu 3y ago
  There is also an interesting response to that video from a leading quantum computer scientist, Scott Aaronson: https://scottaaronson.blog/?p=5460 https://scottaaronson.blog/?p=5460 He actually goes into significant details about your exact question and proposes some resolutions. It's quite long and I don't think I can do it justice in a TLDR so leaving the link to speak for itself.
  - dataflow 3y ago
    Thanks for the link! I'll take a look. Edit: I just read it and I don't feel like he really answered the question. He had a rebuttal about being able to freely specify parameters, but then his Facebook friend addressed his rebuttal, to which he replies "this is indeed more interesting"... which, well, it certainly is, and also doesn't answer the question! (Well, I guess he also mentions we should expect speedup greater than Avogadro's number, which seems fair, but clearly that's not the bar anyone is claiming to meet, so it doesn't get us anywhere.)

avidphantasm 3y ago

Regardless of how good our classical or quantum computers get, simulating “complex” natural systems is ultimately limited by our ability to observe and measure the physical properties of the “components” (I put quotes here to acknowledge the difficulty/impossibility of delineating system components) of that system. I’m not sure quantum computers will help with that.

sfpotter 3y ago
You're missing the point of the question.
- avidphantasm 3y ago
  I’m saying that for some problems, neither classical nor quantum computers may arrive at an acceptable answer.

CrampusDestrus 3y ago

When you break a stick you just break a stick. When you simulate breaking a stick you know everything about the broken stick. What if you broke the stick to study its material properties? Then you would need to spend months carefully taking samples and measuring all the broken spots. With a perfect simulation? You're done the moment it ends. All the data is there available with a copy paste

hutzlibu 3y ago
"With a perfect simulation? You're done the moment it ends. All the data is there available with a copy paste" As far as I understand, to perfectly simulate reality, you would need a second reality.
- wholinator2 3y ago
  Well of course the simulation is a simulation. They are speaking of the ideal case. A real simulation is an application of a model, the physics of the molecules and structures interacting. They are saying that in the ideal case, once the simulation is complete you have complete knowledge of the entire system at every moment in time. Of course there's a resolution to all this. The time steps are comparatively large to the planck time and the wave functions are approximations, everything is an approximation, that's what makes it a simulation. But the principle is that within your model, once the simulation is complete you know _everything_. You have measured every aspect of reality possible from your simplified version. If your model was arbitrarily close to reality you really would know everything

mistermann 3y ago

I wouldn't think so in the case of a stick breaking, but if you consider a more realistic scenario like running a risk analysis across a hyperdimensional problem space, there is certainly something extremely interesting going on there.

D4ckard 3y ago

You are right, basically anything can be viewed as a computation. Ray Kurzweil discusses this extensively in his book The Singularity is Near, building upon previous work by Edward Fredkin. > To appreciate the feasibility of computing with no energy and no heat, consider the computation that takes place in an ordinary rock. Although it may appear that nothing much is going on inside a rock, the approximately 1025 (ten trillion trillion) atoms in a kilogram of matter are actually extremely active. Despite the apparent solidity of the object, the atoms are all in motion, sharing electrons back and forth, changing particle spins, and generating rapidly moving electromagnetic fields. All of this activity represents computation, even if not very meaningfully organized. (From The Singularity is Near Chapter 3, The Limits of Computation)

Strilanc 3y ago

The key detail you're missing is that the problem must be written down. All details must be specified, so that you can unambiguously tell how well it's being solved. Yes, you can write down a problem inspired by a specific stick. And yes, the written down problem will of course inevitably differ in the details from the real stick. Normally you'd think of these small differences as small errors in the description. But as soon as you try to argue the stick is computing the written-down problem, they become errors in the stick because they affect its ability to implement the problem you wrote down.

carabiner 3y ago

It's like saying you can breathe, yet a computer might take a long time to simulate every chemical process taking place in your body in those 2 seconds of respiration.

jcims 3y ago

I wonder about that frequently. The universe 'executes' physics in, as far as I can tell, a realtime basis (at least within the local reference frame). What is that called as compared to computing a model of the same.

wanderingstan 3y ago
Of course for you it feels like realtime, because the physics of “you” are being executed on the same “system”. It’s funny to think that if we are living in a simulation, that the machine we’re running on might have horrible uptime, but we’d never know because our “time” only works when the machine is running!
- beebeepka 3y ago
  Just like a tick rate in a game
chaboud 3y ago
Why do you think time dilation needs to occur in our simulation? Be it from instance-shard transition due to cell crossing (special relativity) or inter-node lag due to spatial density (general relativity), system design constraints dictated the very rules of our “physical” existence. (Poe’s Law notice: yes, I’m joking)

somenameforme 3y ago

Oddly enough, I think this can be answered by headlines alone. Imagine you could do anything remotely interesting with a relative speedup of 47 years to 'instant', where we can say an instant is 1 millisecond. That'd mean in one day of calculation, you could do things that'd take a current era supercomputer more than 4 billion years to achieve. And so on upward from there. Yet we're focusing on this odd and relatively boring metric of 47 years? That suggests that the implications intentionally provoked by the phrasing "Google’s quantum computer instantly makes calculations that take rivals 47 years" are obviously false, even if the statement itself is true in some extremely specific context. So in other words, when genuine quantum progress has been achieved - I don't think we'll need to debate it, as the results would speak for themselves.

Mizoguchi 3y ago

I think a more fair comparison would be that you know how to break the wooden stick so that you end up with one piece measuring exactly 152 mm and you can repeat the feat every single time with other wooden sticks of different dimensions crafted from different trees under different environmental conditions.

robot_no_421 3y ago

You're not modeling or predicting anything though. That's like saying "what if I built a bridge that failed on the first day? A computer would need several days to calculate all the forces that led to the failure, but my bridge failed just fine without any computer help". Well... yes. But try building a bridge that doesn't break. Or to keep with your scenario, try to predict exactly where and how your stick will break before you break it. You can't.

ori_b 3y ago
Does Google's implementation of quantum computing help with this sort of scenario, or is it a really fancy way of breaking the bridge?
- robot_no_421 3y ago
  Yes, and no. Don't ask me rhetorical questions if you don't want a rhetorical answer.
- __MatrixMan__ 3y ago
  Well you don't have to sacrifice any sticks or bridges to see what happens, so that's a plus. One could imagine stimulating experiments that are implausible to actually perform.
  - ori_b 3y ago
    Yes, but that's nothing new -- we've had computers that were used to solve simulations faster than digital comuters could by setting up electronic (or hydraulic, or pneumatic) parts that simulated the terms of the differential equations: https://en.wikipedia.org/wiki/Analog_computer https://en.wikipedia.org/wiki/Analog_computer Is this quantum computer another iteration on the same concept, or is it solving things that are polynomially harder to simulate classically?

riwsky 3y ago

Your wooden stick is dedicated hardware for computing the behavior of wooden sticks. Fascinating? Pretty subjective—but one of the best concrete proxies we have for "fascination" is "economic value" (cf OpenAI's AGI definition). Is it going to make (or save) you a lot of money to quickly find out how that stick broke? Probably not.

gnramires 3y ago
I think you can make the case that, for example, going out, taking a stick from a forest, breaking it and record the sound will be much more economical than trying to simulate a realistic stick breaking sound -- in particular in developer time trying to model sticks and wood breaking sounds in a convincing way (suppose we need say an art asset for a game). It's something complexity theory isn't well prepared to tackle, at least on first look. Complexity theory doesn't take into account the cost of devising an algorithm itself. And complexity theory usually only is interested in asymptotic behavior -- different in both ways from what we have (n=1 and algorithm cost). I think simulations win only when there are significant gains to be had over just doing it in real life, i.e. when you are only interested in a simple aspect that can be summarized by a model, or when for some reason the real life event uses a lot of energy or costs significantly. An extremely accurate simulation of wood and wood breaking, and sound, I think would be quite computationally costly -- the wood is already very complex (not as complex as the base atomic reality -- you probably don't need to model every single atom -- but still very complex). Sticks are cheap, and breaking a stick is easy. Breaking the stick doesn't seem to take much energy, and realistically stick breaking itself (although perhaps not stick collecting) comes out ahead energetically! It gets quite complicated quickly, and it really depends on what you want to model, but I think it's interesting to see when and if simulations are advantageous (for example, you could take the cost of raising a tree into account, or not! is the stick "free" because it would grow and decay anyway?). I think in the long term many things can be simplified into what we're interested, so models increasingly win. But realistically (in our limited lives and limited universes :)) I think there will always be a place for physical experimentation, taking pictures of sticks and recording the sound as they break. (and hopefully our relationship with trees and sticks itself still lasts for a long time...) I say that as someone who really enjoys modelling nature! :) I think modelling and trying to recreate natural process (sometimes with an artistic touch as well) is a great way to understand and appreciate the wonders of the universe. Note: Also, even with ideal reversible 0-cost computation, there's likely to be some kind of polynomial time overhead to 1:1 simulation of reality. This can be enough to justify experimentation instead of simulation, in some cases, when your model itself isn't a significant simplification over reality.

ablatt89 3y ago

Any problems where the configuration space is large, and you want to find some optimal configurations to the problem, would in theory benefit since you can directly map the configurations into the entangled qubits. Entangled qubits give you the ability to physically represent large configuration spaces. The difficult is ensuring entanglement between qubits, scaling up the qubit count, noise reduction between the qubits and the other physical parts of the quantum computer, error correction, and generating the circuit to represent the optimization problem, formalizing a proof that the total time of quantum computation (computation + preparation) is less than to simulate on high performance computers and what not. There's several YouTube videos where some company has mapped their problem into a quantum circuit and claim it provided solutions to optimization problems that they couldn't have found classically but dunno, I guess it would really require AB testing between classically computing it on an HPC versus a quantum computer.

aleksiy123 3y ago

If you need to measure a billion sticks breaking the simulation might start to come out ahead in terms of cost. I think this makes more sense if you use a bridge instead of a stick. Building a full sized bridge to test your idea is prohibitively expensive but a simulation is cheaper to build even if the actually simulation is slower to compute. In real life simulations, small prototypes , and full size prototypes are all useful with various trade-offs of cost and benefits at various stages.

marcosdumay 3y ago

> so does this imply I'm doing anything particularly fascinating If you mean "useful", then I'd like to point our that breaking rods is a common task in many labs all over the world exactly because it can calculate some things better than any non-rod computer we have. If you literally meant "fascinating", then you'd have to ask yourself. For a lot of people, it is.

fnordpiglet 3y ago

The key is things are interesting if they’re interesting to someone. The fact you can break a stick and observe in detail in real time at a minute level better than a computer is very interesting to many people. Botanists, biologists, material scientists, architects, industrial engineers, etc. It’s just not interesting to you. Likewise even contrived quantum experiments like this aren’t interesting to many people. They’re not practical. But they’re profoundly interested to people interested in quantum computing. They’re milestones on a roadmap. There will and are things computer computers won’t do better than classical computers and there are things in reality neither will simulate, and those things are interesting to someone. In fact I think this is a crucial part of basic science- EVERYTHING is interesting. Even the lack of something interesting is certainly interesting to a psychologist :-)