Can the same be said about a quantum system?Yes
Do they ,then evolve in discrete ways and not in a continuous fashion except when viewed as part of a classic system?Large objects are made up of quantum particles. The individual particles act in a quantum fashion and the large object acts in a classical fashion. By large object I am talking about 10^23 particles and larger.
Large objects are made up of quantum particles. The individual particles act in a quantum fashion and the large object acts in a classical fashionThanks. Do the quantum systems evolve in discrete ways rather than continuously?
Thanks. Do the quantum systems evolve in discrete ways rather than continuously?I thought I just answered that question. If your asking just about quantum particles then the answer is quantized or discrete.
I think I was trying to distinguish between quantum particles and quantum systems.Thanks. Do the quantum systems evolve in discrete ways rather than continuously?I thought I just answered that question. If your asking just about quantum particles then the answer is quantized or discrete.
Do they evolve in discrete ways and not in a continuous fashion except when viewed as part of a classic system?There may be a confusion here between:
Can quantum system be said to evolve (I think so)?Yes. Without measurement the wavefunction evolves by the TDSE. Since the wavefunction determines everything that can be known or measured for the system, we can reasonably say that the system evolves (changes with time) if the wavefunction changes with time.
Do they ,then evolve in discrete ways and not in a continuous fashion except when viewed as part of a classic system?This is where it gets a bit interesting. The wavefunction can evolve smoothly BUT you cannot go out and see or observe the wavefunction. The tea cup infront of me has a wavefunction but I cannot see it, hear it or smell it. I have no equipment with which I could measure it and indeed no Physics laboratory has the equipment to measure and record the wavefunction of my tea cup. It is generally thought that the wavefunction is not any sort of physical thing.
PS: I hope I haven't simplified/twisted quantum field theory beyond all recognition!Most of it makes sense, you haven't lead many people astray and you didn't accidentally destroy Canada on the way - so that's all good.
..... the measurement "collapses" the wave function, so that the imaginary part of the wave function disappears, and you are just left with the real values.That's probably the bit that might give some people the wrong idea.
There must be a finite time interval associated with the collapse of a wave function.You almost need to decide which camp you are in first.
My point is that a wave function is a model, not a property, of a system.You may very well be right. As you may be aware, since the early 1900's (when QM was a new idea), people have been asking "what is the wave function actually a wave in?" It is quite possible to consider the wavefunction just as an entirely abstract mathematical description of the state of a system.
There must be a finite time interval associated with the collapse of a wave function.Since the wave function may actually be something physical, a few scientists have looked into this.
The "detection" is some process that first triggers wave function collapse, there may be some collapse time and then the detector will click and we declare the entire detection process complete and the photon was detected.but that involves time reversal. We know that photons travel at a finite speed, so this model implies that the detection event at a distance d behind the slits determines the wavefunction at the slits d/c seconds earlier. Never mind tiny laboratory experiments: it says that every time I look up at the sky, I am influencing events that occurred somewhere between 2 seconds and 14 billion years ago!
there must be some delay between the act of observation and the outcomeThere is also the uncertainty principle; depending on how you structure the experiment:
We can therefore put a lower bound to the collapse speed c′ of 1550 times cThis is what Einstein criticised as "spooky action at a distance".
I think the arguments of Camp 2 are absurd (inanimate objects being able to predict their fate)I assume that you also dismiss the "many worlds" interpretation (held in high credence by Sean Carroll)?
What might be the maximum number of coefficients for a typical quantum object and what might they correspond to?Sadly, there could be an infinite set of eigenfunctions, so that means you could have an infinite set of coefficients.
Alternatively what might be a typical quantum object with very few such coefficients?Probably something like the state of a system expressed in an eigenbasis of spin states. If you were only interested in measuring the z-component of spin of your system, then you can just express the wave function in a basis where you will only have as many eigenfunctions as the system has spin states (so that'll be just two for an electron -> one for spin up and one for spin down).
Might there be such an object with ,say only 4(to represent spacetime)or 5 or 6 (to represent additional properties)?See above. It's important to recognise that the eigenfunctions and what we call the "basis" or "eigenbasis" we use to describe the space of wavefunctions will usually change depending on the observation(s) we may be making.
ES said: "detection" is some process that first triggers wave function collapse.Not necessarily. We could try to make a quick reply to Alancalverd's point (maybe a paragraph) or else we can set a firmer background to make everything clearer and then hit the comment much more squarely. We're going to go for a half-and-half approach. One page to set the background and one page to answer Alancalverd's comment.
Alancalverd replied: ...but that involves time reversal.... Never mind tiny laboratory experiments: it says that every time I look up at the sky, I am influencing events that occurred somewhere between 2 seconds and 14 billion years ago!
ES said: We can therefore put a lower bound to the collapse speed c′ of 1550 times c
Evan-au replied: This is what Einstein criticised as "spooky action at a distance".
I assume that attempts to test the Bell inequality are measuring something related?
https://en.wikipedia.org/wiki/Bell%27s_theorem
I assume that you also dismiss the "many worlds" interpretation (held in high credence by Sean Carroll)?I don't know about alancalverd but I quite like the many worlds interpretation.
- This assumes that in measuring the arrival of a photon at a detector, the entire universe branches into two versions, one in which the photon ends at one detector, and another where the photon ends at the other detector?I don't know why there's a question mark at the end of this. Yes. Although, there's really no reason why the branching should only occurr when there was a set of different outcomes. The branching may just happen all the time, say every second (possibly using co-moving co-ordinate time). It's just some nominal attempt to be as economic as you can be with the creation of whole new branched universes, you do only need them when there was a different set of outcomes possible. I'm really not sure that Nature has the same view of things as a human being and sees the creation of new parallel universes as some work and therefore wishes to make as few as possible.
I assume that you also dismiss the "many worlds" interpretation (held in high credence by Sean Carroll)?Again, it's a mathematical model and doesn't imply that there are many worlds! Feynman used to talk about multiple alternative paths, and that nature followed the path of least action, but never said why!
5) Has it Ever happened that a Coin was tossed & it Disappeared into thin air & never landed.Eddington said that the student of physics must become accustomed to having his common sense violated five times before breakfast, and if he disappeared through the floor and rematerialised in the cellar, he would not consider it mysterious but merely a lucky observation of a very rare phenomenon.
1) If a Billion people Toss, someone might get Heads a hundred times in a row.The probability of scoring 100 consecutive heads is obviously 1/2100, which is a lot less than a billion. You would have to do the trial a billion billion times to be reasonably sure that it happened.
Sheer chance or Probability?
Let's say it a is binary system.Let's take the star Algol as an example (an Arabic name meaning "the ghoul"; sometimes called the demon star)
If we observe 2 stars at a very great distance and the light arriving from them only amounts to a very low number of pixels , are there any quantum effects involved in the observation?
1) If a Billion people Toss, someone might get Heads a hundred times in a row.I don't understand what you see as the difference between the words "chance" and "probability" as used in your sentence, sorry.
Sheer chance or Probability?
2) While Coin is in air, is it Heads & Tails both at the Same time.If you treat the coin as a QM object then you could consider it as being in a superposition of states while in the air. Most people wouldn't treat a real world coin as a QM object, it's a macrosocopic object.
Superposition?
3) Say the Coin is tumbling down Stairs(t1 t2 t3 t4 t5)Is this a metaphor for people who exist in different universes as described in the many worlds interpretation of QM? If it was then yes, they can see different results and they see them simultaneously. The branched worlds were just the one world until branching occurred. So whatever event or outcome lead to the branching, that should have happened when the same past applied to all the worlds created in that branching. Since the different worlds should not influence one another after branching, it's a bit arbitrary to ask if their time co-ordinates or flow of time would continue to be synchronous afterwards. However, the same laws of physics should apply in all branches.
If i exist inside of Only t3, i see Heads, but Others existing inside t1245 can see anything at Random(headsORtails)
Simultaneity?
What i am tryin to ask is, can/has the Wave Function ever predicted an Inaccurate result, or is it 100 % Correct every single time.For certain, physicists sometimes make inaccurate predictions. Furthermore, Quantum Mechanics is almost certainly not the final or ultimate theory that models and explains everything corrrectly.
Uncertainty?
5) Has it Ever happened that a Coin was tossed & it Disappeared into thin air & never landed.Maybe. QM predicts some incredibly strange things.
(lol sorry)
If we observe 2 stars at a very great distance and the light arriving from them only amounts to a very low number of pixels , are there any quantum effects involved in the observation?I think most of us are interpreting "low number of pixels" as indicating only a low number of photons were also received.
How many pixels would you need to form any kind of a judgement as to position and relative moment between them?This sounds very specific to the equipment being used and what was being attempted. The light probably went through some imperfect lens before it was brought to focus on this light recpetor, it almost certainly went through a lot of air in our atmosphere. QM effects that may happen involving detection at a pixel aren't the most limiting effect.
If we observe 2 stars at a very great distance and the light arriving from them only amounts to a very low number of pixelsDon't confuse between photons (what the source emits) and pixels (how the receiver is constructed).
How many pixels would you need to form any kind of a judgement as to position and relative moment between them?Two. If we initially detect intensity I1 at pixel A and 0 at A + 1, then subsequently detect I A < I1 and I A+1 > 0, we can infer that the binary is rotating.
any pixel can be activated in principle by a single photon.I'm not an engineer and I honestly don't know what sort of detection devices exist so I went shopping on the internet. Does "in principle" mean ?4, 000 (four thousand GBP) per pixel?
If we initially detect intensity I1 at pixel A and 0 at A + 1, then subsequently detect I A < I1 and I A+1 > 0, we can infer............ that the pixels just don't click with 100% effectiveness? that the air changed its density locally? or maybe that the source image was rotating.
Hi.
I think many of your ( @geordief ) questions have been reasonably answered by others already. Here is just a quick reply to each.
i had Observed this before, in another Thread, you perhaps were referring to me, but you ended up typing Origin's nickname.
I thought it must be a typo or system error.
But here We are, it seems to have happened again.
Instead of my nickname, you typed Geordief's.
But i still Wish to confirm this, was this a typo, or is there a Glitch in the System?
Coz in another Thread, i had typed Varsigma's nickname expecting a response from them, but instead Neilep ended up responding.
Is This phenomenon taking place with Anybody Else?
(to clarify a bit, i type username @abcde...i see it as @abcde.
But the user @abcde sees it as @1234567.
& eventually user @1234567 ends up responding to me, on a query, which i had asked to user @abcde)1) If a Billion people Toss, someone might get Heads a hundred times in a row.I don't understand what you see as the difference between the words "chance" and "probability" as used in your sentence, sorry.
Sheer chance or Probability?
There is No difference.
Sorry i confused you.
Rephrase - if a billion people toss the Coin, one of em gets heads 10 times in a row.
This is simply Probability Right?
Not a Miracle!2) While Coin is in air, is it Heads & Tails both at the Same time.If you treat the coin as a QM object then you could consider it as being in a superposition of states while in the air. Most people wouldn't treat a real world coin as a QM object, it's a macrosocopic object.
Superposition?
Most people are Sane enough to Not do that.
Agreed!
((2) - got it)3) Say the Coin is tumbling down Stairs(t1 t2 t3 t4 t5)Is this a metaphor for people who exist in different universes as described in the many worlds interpretation of QM? If it was then yes, they can see different results and they see them simultaneously. The branched worlds were just the one world until branching occurred. So whatever event or outcome lead to the branching, that should have happened when the same past applied to all the worlds created in that branching. Since the different worlds should not influence one another after branching, it's a bit arbitrary to ask if their time co-ordinates or flow of time would continue to be synchronous afterwards. However, the same laws of physics should apply in all branches.
If i exist inside of Only t3, i see Heads, but Others existing inside t1245 can see anything at Random(headsORtails)
Simultaneity?
& what if t12345 was Time, and i checked heads/tails 5 times.
Will i see a Pattern emerge?
t1h t2t t3h t4t t5h
Or
t1t t2h t3t t4h t5t
Or
t1h t2h t3h t4h t5h
Or
t1t t2t t3t t4t t5t
Will i be able to Predict future readings of t6 t7 t8 t9 t10 based on emergent pattern or Do the Readings remain Absolutely Random without predictable Patterns?
(t/1/h --- time/1/heads
&
t/1/t --- time/1/tails)What i am tryin to ask is, can/has the Wave Function ever predicted an Inaccurate result, or is it 100 % Correct every single time.For certain, physicists sometimes make inaccurate predictions. Furthermore, Quantum Mechanics is almost certainly not the final or ultimate theory that models and explains everything corrrectly.
Uncertainty?
There are many inherent problems with Quantum Mechanics. Problems concerning measurement and wave function collapse have been discussed elsewhere. Other problems include assuming a particle does have a mass - which you will need to do when constructing the Hamiltonian that appears in the Shrodinger wave equation. QFT is one extension of (basic) Quantum Mechanics where "mass" doesn't have to be an inherent property of particles (it can be just an interaction from a field). QM, even in the more developed form of QFT, still doesn't reproduce results consistent with all of General Relativity (GR).
Cordially agreed!
QM is Incomplete.
((4) - got it)5) Has it Ever happened that a Coin was tossed & it Disappeared into thin air & never landed.Maybe. QM predicts some incredibly strange things.
(lol sorry)
Strange things like Virtual Particles?
That pop into existence from nothing & go back into nothing.
If VPs are truly physical, Why then does the Universe not glow with a Blinding light when matter/antimatter VP pairs collide?
Or VPs just exist in 2d sheets of mathematical equations & the Energy released from anti/matter collisions remains trapped behind thick book covers, busy illuminating the bookmarker Within.
Best Wishes.
Much Appreciated & Thanks!
I also thought these SPD (single photon detectors) were considerably less than 100% effectiveA cryogenically-cooled semiconductor sensor as used by astronomers has something like 70% photon-capture efficiency, at chip level.
Will i be able to Predict future readings of t6 t7 t8 t9 t10 based on emergent patternAs far as we can tell, quantum phenomena are truly random.
Instead of my nickname, you typed Geordief's.I.T. support would say it was a PEBKAC issue (problem exists between keyboard and chair).
Quote from: alancalverd on Today at 09:21:10Detection efficiency isn't relevant - you have to integrate over a reasonable period to determine intensity.
If we initially detect intensity I1 at pixel A and 0 at A + 1, then subsequently detect I A < I1 and I A+1 > 0, we can infer.......
..... that the pixels just don't click with 100% effectiveness? that the air changed its density locally? or maybe that the source image was rotating.
The example you found appears to be a photomultiplier tube, which (in the past) tended to be a single pixel, ie not an image-forming device? (I am sure alancalverd will know!)Not really even a pixel, though we have used arrays of photomultipliers to determine the location of an event in a scintillator crystal or swimming pool full of carbon tetrachloride*, and display the resulting vector as a pixel on a flat screen.
Air density and turbulence may have been problems for neanderthal astronomers, but any respectable Waitrose customer buys his data from space telescopes nowadays.If you want high resolution images of really faint objects, the best option is still to use really large telescopes on top of really high mountains (a number of them in the Atacama desert of South America).
- I am assuming that the calculations involved treating light from the star as a classical light wave passing through a classical medium with time-varying refractive index, so no quantum effects need to be calculated.At some point in the system, you need to generate an electrical signal representative of the wavefront distortion. This involves a photon-electron converter (usually a CCD), which, like all photon detectors, employs quantum phenomena!