Hopefully thus question makes some kind of sense…
Without consideration of the observed reality, which of the following statements should be considered most extraordinary?
1/ of a particular elementary particle, every example in the universe is exactly identical.
2/ of a particular elementary particle, every example in the universe is in some way unique.
In terms of the demands of the propositions.
2/ of a particular elementary particle, every example in the universe is in some way unique
Why?
if I dip my hand into a stream take it out and then put it back in, is the stream the same stream I put my hand into the first time?
1 is most extraordinary as 2 is reality.
>if I dip my hand into a stream take it out and then put it back in, is the stream the same stream I put my hand into the first time?
Am I upstream or downstream.
>1 is most extraordinary as 2 is reality.
I tended to intuitively go to that, but thought the question was more of the abstract propositions.
Huh?
Wikipedia said:
Identical particles, also called indistinguishable or indiscernible particles, are particles that cannot be distinguished from one another, even in principle. Species of identical particles include, but are not limited to elementary particles such as electrons, composite subatomic particles such as atomic nuclei, as well as atoms and molecules. Quasiparticles also behave in this way. Although all known indistinguishable particles are “tiny”, there is no exhaustive list of all possible sorts of particles nor a clear-cut limit of applicability; see particle statistics #Quantum statistics for detailed explication.There are two main categories of identical particles: bosons, which can share quantum states, and fermions, which do not share quantum states due to the Pauli exclusion principle. Examples of bosons are photons, gluons, phonons, and helium-4 nuclei. Examples of fermions are electrons, neutrinos, quarks, protons, neutrons, and helium-3 nuclei.
The fact that particles can be identical has important consequences in statistical mechanics. Calculations in statistical mechanics rely on probabilistic arguments, which are sensitive to whether or not the objects being studied are identical. As a result, identical particles exhibit markedly different statistical behavior from distinguishable particles. For example, the indistinguishability of particles has been proposed as a solution to Gibbs’ mixing paradox.
i would have gone for 1 too. purely because of the old saying that there is really only one electron in the universe. or something like that.
:-)
It depends what you mean by identical.
Fundamental particles have some properties that are identical (or so we believe), and some properties that are all different, such as position and momentum.
Reading the actual question, I’d go for 1) as being the more extraordinary.
The Rev Dodgson said:
It depends what you mean by identical.Fundamental particles have some properties that are identical (or so we believe), and some properties that are all different, such as position and momentum.
The Rev Dodgson said:
It depends what you mean by identical.Fundamental particles have some properties that are identical (or so we believe), and some properties that are all different, such as position and momentum.
Ahh, good point.
So I’d like to exclude position and momentum in the original question.
It just seems odd to me that the universe is able to pump out, for example, uncountable numbers of identical photons from many disparate sources which are not identical to each other, or even (light bulbs, biochemical reactions, stars etc). On the other hand, if particular elemental particles were not all identical, the universe would probably be a very weird place (if it existed at all).
I guess my questions aren’t very well formed. I guess, with the engineering aspect alluded to in the thread title, what I’m thinking is that when we manufacture a bunch of components we can not make them exactly identical, no matter how hard we try. But the universe is able to do that. These are fundamental particles, but is there some more fundamental process behind these particles which allows the universe repeat production of stuff with such stunning accuracy?
>These are fundamental particles, but is there some more fundamental process behind these particles which allows the universe repeat production of stuff with such stunning accuracy?”
Perhaps not ‘process’ as we’d conceive so, but I think the answer to your ponderance is yes.
Some aspects of what may be perceived and conceived as ‘repeat production’ is an artifact of thermodynamics and the way our minds have been shaped to conform to that thermodynamics for survival, but i’d expect there are other ways of seeing it, though these other ways may be constrained by the usefulness of them.
Hope that reads alright, go find my glasses, screens a blur.
The thing that does the ‘work’ in the universe is mostly ‘energy state transition’, whereas humans probably view the world more from slower energy state transitions (which we may even view aspects of as somewhat static, though little or nothing is).
What appears to be the case is that it’s not (perhaps so much) physical things with mass that gives all of the universe predictable characteristic physics, not what we view as ‘solid’.
Counterintuitive it may be, but I believe transitional states of energy are the ‘container’ that generates not just structure, but perhaps more importantly ‘the possibility of structure’.
The Rev Dodgson said:
It depends what you mean by identical.Fundamental particles have some properties that are identical (or so we believe), and some properties that are all different, such as position and momentum.
I nearly said something about position and momentum in my earlier post, but I assumed that esselte wasn’t so interested in those particular observables.
Stealth said:
Yes, I allowed for position as the distinguishing feature. No two particles can occupy the same location in space time.
Actually, they can, especially if they are bosons. Two fermions can occupy the same space (or to be more precise can be in the same position state) as long as all their other properties are not also identical. Eg, in a neutral Helium atom in the ground state the 2 electrons are both in the 1s orbital. This means they both have the same energy and the same (linear) momentum state, and they also have the same position state. But they satisfy Pauli exclusion because their quantum spin states are anti-parallel to each other, i.e. they have opposite intrinsic angular momentum.
I nearly said something about position and momentum in my earlier post
as long as you didn’t mention them in the same post….
esselte said:
So I’d like to exclude position and momentum in the original question.
esselte said:
It just seems odd to me that the universe is able to pump out, for example, uncountable numbers of identical photons from many disparate sources which are not identical to each other, or even (light bulbs, biochemical reactions, stars etc). On the other hand, if particular elemental particles were not all identical, the universe would probably be a very weird place (if it existed at all).
Our scale of existence is way too big to see most quantum phenomena directly. Our senses & brains operate in the macroscopic world so they’ve evolved & been trained to work with objects containing huge numbers of fundamental particles. This masks a lot of the quantum behaviour of stuff, so it’s not surprising that these quantum properies can seem odd in comparison to the properties we’re familiar with in our macroscopic world.
I suppose the key point relating to your OP is that quantum rules tend to restrict the degrees of freedom of a system. It’s hard to notice that directly at our normal macroscopic level, but it becomes quite obvious in small quantum systems, like atoms. The electrons in an atom are restricted in the combinations of energy, momentum and position that they can have. These restrictions give rise to the spectra produced when atoms are excited into emitting light, they also give rise to the chemical properties of the atom.
According to quantum field theory, particles are simply excitations of some quantum field. It doesn’t matter where or when you excite that field, the types of excitation possible will always be the same. So it may be helpful to think of fundamental particles as a type of process rather than as a type of thing, with quantum rules limiting how that process can procede.
So when you excite the electron field, it is restricted in how it can respond. The simplest excitation of the electron field gives rise to an electron, or if you “invert” the excitation you get a positron. If you excite it more, you’ll get more electrons (or positrons), but you can’t get fractional electrons, or electrons that are a bit bigger or a bit smaller (in terms of their rest mass & electric charge) than the basic quantum unit.
esselte said:
I guess my questions aren’t very well formed. I guess, with the engineering aspect alluded to in the thread title, what I’m thinking is that when we manufacture a bunch of components we can not make them exactly identical, no matter how hard we try. But the universe is able to do that. These are fundamental particles, but is there some more fundamental process behind these particles which allows the universe repeat production of stuff with such stunning accuracy?
When we manufacture components, they contain vast numbers of particles. In contrast, an atom only has a fairly small number of components, and they’re restricted in how they can behave and interact, similar to how Lego bricks are restricted in how they can connect together. And as for the fundamental particles themselves like photons, quarks and electrons, they don’t actually have components so there’s not much room for variation. :)
But even with composite particles like protons, the behaviour of its component quarks is so restricted that there’s nothing you can do to a proton (short of disrupting it) to make it permanently different to all the other protons in the universe, although you can temporarily jiggle its quarks around a bit.
…
There might be some more fundamental process underlying the particles of the Standard Model: superstring theory postulates that all of the so-called fundamental particles are simply different modes of vibration of even more fundamental strings; these strings themselves aren’t made of any kind of stuff, they are just strings of spacetime.
If that theory is true it may be possible to transform a particle into another type of particle in a way that the Standard Model says is impossible due to various conservation laws which we’ve never observed to be violated. The theory also implies that there are a whole bunch of possible vibrational modes corresponding to particles we’ve never observed: for every fundamental fermion there should be a supersymmetry boson partner, and vice versa.
It takes a huge amount of energy to invoke such transformations – the kind of energy density that isn’t normally found in the universe except for a fraction of a microsecond after the Big Bang, and different versions of string theory disagree on how much energy is needed for a given reaction. The LHC may be powerful enough to invoke some of the supersymmetry transformations that are forbidden by the Standard Model, or even to produce some of those supersymmetry partners, but it hasn’t so far, which tends to imply that those versions of string theory are wrong.
JudgeMental said:
I nearly said something about position and momentum in my earlier postas long as you didn’t mention them in the same post….
That’d be ok, as long as I don’t try to be certain about them both at the same time. :)
esselte said:
I guess my questions aren’t very well formed. I guess, with the engineering aspect alluded to in the thread title, what I’m thinking is that when we manufacture a bunch of components we can not make them exactly identical, no matter how hard we try. But the universe is able to do that. These are fundamental particles, but is there some more fundamental process behind these particles which allows the universe repeat production of stuff with such stunning accuracy?
That seems to me very likely.
I suppose string theory could be said to be a theory of that fundamental process, or at least the start of a first attempt at such a theory.
I found the question interesting, and thought it put in a way that provoked thought.
They have different locations and momentums…
esselte said:
Hopefully thus question makes some kind of sense…Without consideration of the observed reality, which of the following statements should be considered most extraordinary?
1/ of a particular elementary particle, every example in the universe is exactly identical.
2/ of a particular elementary particle, every example in the universe is in some way unique.
This question makes more sense if you substitute the word “multiverse” for “universe”.
mollwollfumble said:
esselte said:
Hopefully thus question makes some kind of sense…Without consideration of the observed reality, which of the following statements should be considered most extraordinary?
1/ of a particular elementary particle, every example in the universe is exactly identical.
2/ of a particular elementary particle, every example in the universe is in some way unique.
This question makes more sense if you substitute the word “multiverse” for “universe”.
In a topological multiverse every example of a particular elementary particle is identical.
In a quantum multiverse most examples of a particular elementary particle are identical.
In a multi-inflation multiverse every example of a particular elementary particle is different in each universe.