Technological Singularity

[Mr. Tea]

There is no reason to believe quantum computers can do that. QC can speed up some computations like the factoring of integers (which would be problematic for the kind of cryptography used today to secure the internet.

Is that so? Shame, I was probably getting confused with Penrose's quantum tubules again. Which can supposedly decide non-computational problems because they're quantum-gravitational tubules. Naturally!

Speaking of biological intelligence, I think it's pretty cool that a slime mould can solve a maze:

Never mind a lack of nerve cells, slime moulds don't even have separate cells - they're just a naked mass of protoplasm with nuclei strewn throughout. Lovecraft-tastic!

Edit:

Others discuss if there's substance behind quantum biology.

The subconscious is to consciousness as the quantum world is to the classical world.

Like, duuude, whoaah...

 

[nomadthethird]

There is no reason to believe quantum computers can do that. QC can speed up some computations like the factoring of integers (which would be problematic for the kind of cryptography used today to secure the internet.



Others discuss if there's substance behind quantum biology.

Ok, I just waded through that, and that's not actually what they're discussing. They're discussing whether the effects of quantum physics are trivial in biological systems, which is a different claim.

Quantum biology would be a superimposition of principles from quantum physics over biological processes, but not necessarily over biological systems as wholes, would it not?

 

[3 Body No Problem]

Is that so? Shame, I was probably getting confused with Penrose's quantum tubules again. Which can supposedly decide non-computational problems because they're quantum-gravitational tubules. Naturally!

There are only very few known quantum algoritms (see this list), most are fairly artificial. The big one that put (the idea of) quantum computing on the map is Shor's algorithm for factoring integers. All known conventional (i.e. non-quantum) algorithms for factoring integers run in time exponential in the length of the number, which means they are very slow for large numbers. Essentially all cryptography that you use (whether you are aware of this or not) when you use the internet is based on (the hope) that no fast factoring algorithms exist.

It is not known if Shor's algorithm can be implemented on classical computers.

It is also not known if quantum computers can be built.

Speaking of biological intelligence, I think it's pretty cool that a slime mould can solve a maze:

Never mind a lack of nerve cells, slime moulds don't even have separate cells - they're just a naked mass of protoplasm with nuclei strewn throughout. Lovecraft-tastic!

That's brilliant. How do they do it?

 

[3 Body No Problem]

Ok, I just waded through that, and that's not actually what they're discussing. They're discussing whether the effects of quantum physics are trivial in biological systems, which is a different claim.

No, it's the same, just more politely expressed.

The question is: do we to go down to the level of QM to explain biological phenomena, i.e. how the proteins work in cells, or can all of this be explained classically?

The people who are argue for quantum biology all say: in the future we will find biological effects that can only be explained with reference to quantum phenomena. Their detractors say: there is currently no example where we know that it cannot be explained classically, please quantum biology guys & girls show us one.

A strong form of detractors says: biological entities (like macro molecules) are too large to exhibit quantum effects due to decoherence..

I'm not a physicist, please correct me if I'm wrong, but I think the strong detractor's claim touches on an interesting open problem on physics (which is also key to the question whether we can build real quantum computers): can large systems exhibit quantum effects, or not. Nothing in quantum mechanics as we understand it today says there cannot be macroscopic quantum effects, but there seem to be serious obstacles to scaling quantum effects to macroscopic systems. They may just be engineering problems that will eventually be overcome, but it is also possible that there is a fundamental scale limitation to quantum effects which we don't understand.

Quantum biology would be a superimposition of principles from quantum physics over biological processes, but not necessarily over biological systems as wholes, would it not?

Biology is based on chemistry, and chemisty is based on quantum mechanics. However, for large systems, quantum mechanics (as far as we know) collapses to classical mechanics, and consequently we work with classical physics in biology. The claim of quantum biologists is that there are biological phenomena that cannot be explained classically.

 

[Mr. Tea]

A strong form of detractors says: biological entities (like macro molecules) are too large to exhibit quantum effects due to decoherence..

But macromolecules are made up of micromolecules, aren't they? And micromolecules are made up of atoms. I mean, genetic nucleotides are pretty small, and molecules bigger than that (Buckyballs, for example) have been shown to exhibit explicitly quantum-mechanical behavior, viz. diffracting when you pass a beam of them through a narrow slit.

Then in the brain you've got nitrous oxide acting as a neurotransmitter, and that's only got three atoms - not to mention the individual potassium/sodium ions involved in the transmission of nerve impluses. Decoherence time is, AFAIR, inversely proportional to the size* of the system under consideration, so it's much longer for a single atom or a monocyclic molecule than for, say, a whole protein or something.


*not sure if this means mass or length scale, but doesn't substantially change the argument

 

[nomadthethird]

No, it's the same, just more politely expressed.

The question is: do we to go down to the level of QM to explain biological phenomena, i.e. how the proteins work in cells, or can all of this be explained classically?

The people who are argue for quantum biology all say: in the future we will find biological effects that can only be explained with reference to quantum phenomena. Their detractors say: there is currently no example where we know that it cannot be explained classically, please quantum biology guys & girls show us one.

A strong form of detractors says: biological entities (like macro molecules) are too large to exhibit quantum effects due to decoherence..

I'm not a physicist, please correct me if I'm wrong, but I think the strong detractor's claim touches on an interesting open problem on physics (which is also key to the question whether we can build real quantum computers): can large systems exhibit quantum effects, or not. Nothing in quantum mechanics as we understand it today says there cannot be macroscopic quantum effects, but there seem to be serious obstacles to scaling quantum effects to macroscopic systems. They may just be engineering problems that will eventually be overcome, but it is also possible that there is a fundamental scale limitation to quantum effects which we don't understand.



Biology is based on chemistry, and chemisty is based on quantum mechanics. However, for large systems, quantum mechanics (as far as we know) collapses to classical mechanics, and consequently we work with classical physics in biology. The claim of quantum biologists is that there are biological phenomena that cannot be explained classically.

Ahhhhh...now a couple of things from the debate make more sense.

I don't know, I think I'm with the "Yes" team on this. There are plenty of things that we just can't explain yet with reference to classical explanations (biomechanical ones), viz., for example, how spindle fibers/microtubules move down a cell during mitosis. In fact, there are plenty of microbiological processes that work and we just can't figure out how the cells parts know to move this way or that way--what is attracting them?? This doesn't mean that we will never discover a way to explain them with reference to classical physics, but I wouldn't be shocked if somebody comes up with a wacky and awesome quantum explanation. There does seem to be a gaping whole at the center of microbiology just waiting to be filled by somebody.

Why not think big? (Or small...whatever...)

 

[nomadthethird]

But macromolecules are made up of micromolecules, aren't they? And micromolecules are made up of atoms. I mean, genetic nucleotides are pretty small, and molecules bigger than that (Buckyballs, for example) have been shown to exhibit explicitly quantum-mechanical behavior, viz. diffracting when you pass a beam of them through a narrow slit.

Then in the brain you've got nitrous oxide acting as a neurotransmitter, and that's only got three atoms - not to mention the individual potassium/sodium ions involved in the transmission of nerve impluses. Decoherence time is, AFAIR, inversely proportional to the size* of the system under consideration, so it's much longer for a single atom or a monocyclic molecule than for, say, a whole protein or something.


*not sure if this means mass or length scale, but doesn't substantially change the argument

Oh yes there are some amazingly simple and elegant neurotransmitters, including all kinds of ions. Ca 2+ is a fav of mine.

Are you saying here that the quantum tendencies of a system cohere longer in a more complex system? Or can't this be expressed this way?

 

[Mr. Tea]

Are you saying here that the quantum tendencies of a system cohere longer in a more complex system? Or can't this be expressed this way?

I don't think complexity is the main thing, it's more to do with size. Bigger systems decohere faster, meaning there's less time for quantum interference between different states, not more. Though it seems reasonable to assume bigger systems are generally more complex than smaller ones.

 

[luka]

Thing is, exponential increase just keeps getting gradually steeper and steeper, there's no sudden cut-off moment where everything goes "WHOOSH!" all in one go. I think the idea of the Singularity is that some breakthrough is made which enables not merely a quantitative change in the pace of technological innovation, which after all is happening all the time (Moore's law) , but a qualitative shift so that a graph of processor power or whatever vs. time effectively looks like a vertical wall.

One possible catalyst people have mentioned already could be computers that are better at designing things than we are - genetic algorithms and the like. Another could be quantum computers, which (once some fairly substantial practical difficulties are solved) offer effectively limitless computing power. I think some theorists think they may even be able to solve problems that are even in principle insoluble to classical Turing machines (eg. common-or-garden computers as they exist today). Then there's work people have been doing with pieces of DNA, using base pairs as digits to perform immensely complex calculations...some people think DNA/RNA can unzip and re-zip much more quickly than it 'should' be able to according to semi-classical molecular dynamics, which means the nucleotides may be existing in quantum superposition before actually binding to the phosphate backbone to complete the reaction.

I dunno if it counts as a fully-fledged subdiscipline yet, but people are already writing papers on 'quantum biology'. And some of them have a bit more of a basis in experimental reality than Penrose's magic tubules, too.

its actually pretty cool listening to tea talk about something he knows about.

 

[Mr. Tea]

Nomadologist had a favourite neurotransmitter! I would say we'd have been perfect together, but I fear craner would track me down and murder me in a jealous rage.