Are you referring to entanglement as the process of particles interacting, as the process of propagation of particles through spacetime, or in terms of the act of measurement?danshawen said:
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danshawen
Valued Senior Member
Both. The Chinese satellite split the photon into entangled beams and directed separate beams to two different Earth stations 1500 miles apart, where one entangled beam was observed and the other one 1500 milse away correlated to it. Both processes require a direction to be chosen; one for the wavefronts of the photons to propagate, another to choose to observe them in the direction they propagated.
Think about how direction specific this is. If an entangled communication is being directed at your location right now, how do you know what direction it is coming from without all of this communication protocol being arranged in advance beforehand? As I've mentioned before, entanglement is really not the most practical means of setting up instant communication point to point without prior instructions and protocols from the carrier on how to do so.
The instant communication link cannot be set up until the photons traveling at c arrive at the points they are to be observed, so in a sense they are still limited by the speed of light on the one hand, and the speed of entanglement only comes into play after they arrive.
In a 2-qubit quantum circuit, the qubits can be localised in a quantum well or dot. Since there is no direction of propagation as such, how do you entangle two stationary qubits?
The direction of propagation of photons, which can never be stationary, is an artefact of any photon experiment--using a waveguide instead of a vacuum means a direction of propagation is arbitrary, it can be a loop for instance.
Actually, in a universe which occupies a single point, I imagine communication from point to point (i.e. to the same point) would indeed be instantaneous.
Our universe doesn't occupy a single point. Sad.
The direction of propagation of photons, which can never be stationary, is an artefact of any photon experiment--using a waveguide instead of a vacuum means a direction of propagation is arbitrary, it can be a loop for instance.
I imagine you would not be the first to notice that communication depends on pre-arranged protocols.danshawen said:
. . . hell freezes over?
Actually, in a universe which occupies a single point, I imagine communication from point to point (i.e. to the same point) would indeed be instantaneous.
Our universe doesn't occupy a single point. Sad.
One other observation:
Quantum mechanics is not very precisely named. That happens in science for mostly historical reasons. Some things we call laws of physics are really about relations between different parts of space and time. QM is about relations between probabilities, and probabilities are related to measurement.
But, QM doesn't really say anything about the physics, because it's only about probabilities, except these probabilities are complex-valued, and this makes a really, really big difference.
It means having to think about some kind of fundamental difference between what we understand as information, and what we can store in quantum states (what really is it, and does it matter if we know or not?).
Measurement is not something QM can really tell us much about, we have to 'gerrymander' the logic, to borrow a phrase. QM is about relative phases of completely abstract probability amplitudes, the phases are related to the phases of group velocities in wave mechanics, hence quantum wave mechanics would be more accurate, but it's really quantum gauge mechanics, the gauge (a photon) is what represents a change in phase of a matter-field.
The phases, along with superpositions of amplitudes which can, unlike classical probabilities, be negative and so cancel positive amplitudes, are what gives us the means to store information in quantum states. We get quantum computers because complex amplitudes and the related field of phases are negative or positive, like wave amplitudes.
We don't fully understand the underlying relations, but we do understand the physics (along with its laws), at least well enough to start constructing real quantum computers. This is not a trivial thing.
Quantum mechanics is not very precisely named. That happens in science for mostly historical reasons. Some things we call laws of physics are really about relations between different parts of space and time. QM is about relations between probabilities, and probabilities are related to measurement.
But, QM doesn't really say anything about the physics, because it's only about probabilities, except these probabilities are complex-valued, and this makes a really, really big difference.
It means having to think about some kind of fundamental difference between what we understand as information, and what we can store in quantum states (what really is it, and does it matter if we know or not?).
Measurement is not something QM can really tell us much about, we have to 'gerrymander' the logic, to borrow a phrase. QM is about relative phases of completely abstract probability amplitudes, the phases are related to the phases of group velocities in wave mechanics, hence quantum wave mechanics would be more accurate, but it's really quantum gauge mechanics, the gauge (a photon) is what represents a change in phase of a matter-field.
The phases, along with superpositions of amplitudes which can, unlike classical probabilities, be negative and so cancel positive amplitudes, are what gives us the means to store information in quantum states. We get quantum computers because complex amplitudes and the related field of phases are negative or positive, like wave amplitudes.
We don't fully understand the underlying relations, but we do understand the physics (along with its laws), at least well enough to start constructing real quantum computers. This is not a trivial thing.
Hi there argument (as you wish to be called.) That was an interesting proposal. However IS ob- servation interaction?
I know it's your thread, but you do not have to really crap it with such foolish statements.
For record sake....QM is as good or bad physics as classic physics is and probabilities are never complex valued, these values are always between 0 - 1.
Sorry, that's just wrong, the Hilbert space is $$ \mathbb C^2 $$.The God said:
What you seem to be stumbling along about is something called the 1-norm.
"making the speed of light the basis of time"
Speed has units [distance]/[time] so I see no way to make 'the speed of light' a basis of time without at least incorporating some defined distance. If the metre were defined by (say) the length of a piece of metal then we could have a unit of time that was the time light took to travel the length of that piece of metal. In the real world we have chosen that it is length that is defined in terms of an amount of time and the distance light travels in that amount of time.
" only happens when an interval of time is equivocated to an instant of time,"
I can't extract any meaning from that
" and this is a proportional math equivalent of division by zero,"
?
" a serious mistake "
That you seem to be the only one making.
Imagine you have lost a towel. There may be an amount of time involved before you find it - this is an interval of time between events - there is no distance involved and the concept of speed (distance/time) cannot be applied. Once you find your towel you know 'instantly' that it doesn't occupy any space other than the space you see it in and it doesn't occupy any of the spaces that you looked for it in while you were searching.
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exchemist
Valued Senior Member
I'm confused now. I had thought that the probability of finding a QM entity in a volume of space was given by the wavefunction multiplied by its complex conjugate and then integrated over the volume of space involved. The use of the complex conjugate gets rid of any imaginary part in the result, does it not? In which case the probability value is always real, surely?
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Write4U
Valued Senior Member
From my very limited perspective, that seems a logical question. As I understand it, we do interact with what we observe, but is that proof that this is how things work when we are not observing it?
Try this: http://www.scottaaronson.com/democritus/lec9.htmlexchemist said:
danshawen
Valued Senior Member
Minkowski made the assumption that the speed of light was proportional to time in order to fabricate his Euclidean Pythagorean-complex interval of spacetime. When he did so, he equivocated an instant of time with an invariant speed of light, which is a velocity. A velocity is, AS YOU SAY, a proportion built from a distance (light travel time) divided by time. This error is the same as dividing an interval of time by an instant of time (zero), which makes it into mathematical nonsense.
Anything he concludes after that point, Minkowski intervals, rotation, and a relativity of simultanaeity restricted to a definition of simultanaeity which can never be simultaneous (because he ruled it out with his original error) is likewise nonsense. It would only make sense in a universe in which quantum entanglement did not exist, which is not this one.
Using Minkowski's reasoning, spooky action at a distance can never be considered real, much less understood. In the process, he also eliminated conservation of mass/energy, his poorer student Einstein's most famous relation, which was derived using Newtonian math, not Minkowski / Hilbert mathematical gobbledegook.
Minkowsk's reasoning is why time itself must "stop" for a propagating photon, or something traveling at 0.99999999... x c. It does not. Reality does not recognize a divide by zero, and neither does mathematical consistency, and that's the point. The basis of time is the instant of entanglement state changes. If this is not identically a zero length time interval, it doesn't matter, because nothing in this universe moves faster. It is the simultanaeity that Minkowski never considered because it is not actually faster than light. It is invariant, and it is at rest relative to an all pervading field without which a measurement of the RELATIVE speed of light is impossible, and which has no inertia. Absolute space is nonsense, but absolute time exists in the form of the instant of now.
Boost matrices are only a lasting tribute to this division by zero. Space and time are not related in that way. There is only time. EVERY dimension is light travel time, but the speed of light is not the basis of time because an instant of time cannot be made proportional to a velocity or an interval of time, much less an interval of spacetime. Resorting to complex math or Hilbert space will not save you from an error you made when you divided by zero. I do not exaggerate when I call such reasoning gobbledegook. Math works. Proportional math works as long as you don't divide by zero and tell us you are doing so to better grasp infinity. That isn't just a lie. It's grounds for permanently revoking your PhD in math or whatever else you have by way of credentials. It's pseudoscience masquerading as math.
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I'm certainly no expert but this seems extremely unlikely. Can you show where he did this?
exchemist
Valued Senior Member
Sorry this is long and rather tedious. Can you refer me to the section you have in mind, please?
I think the most relevant part is where constructive and destructive interference is discussed.exchemist said:
Interference is a quantum thing; you get destructive interference where the positive amplitudes are cancelled by negative amplitudes.
This interference is not seen in classical probabilities, where negative amplitudes don't appear. This is why QM is called an extension of classical probability theory.
exchemist
Valued Senior Member
OK but probability amplitude is not probability.
Probability amplitude is that which, when you take its square modulus, gives you the probability density at a point in space, which you then have to integrate over a volume of space to find the probability value associated with that volume.
So yes the idea of probability amplitude is an extension of probability theory, if you like, but probability values themselves are real, I submit.
Quite. This is discussed in the comparison of the 1-norm and the Euclidean 2-norm in the link I posted.exchemist said:
What of information about probabilities, is that real? Is the Schrodinger equation about real probabilities? Is it about measurement?
This is interesting, and knowing something of exchemist's usually excellent posts is likely to be correct.
However - I am unfamiliar the term "probability amplitude". My understanding was that the wavefunction amplitude is that which, when you take the square of its modulus, you get the probability density at a point in space. Care to explain the term "probability amplitude"?
I can let Richard Feynman do that: www.feynmanlectures.caltech.edu/III_03.htmlQuarkHead said:
danshawen
Valued Senior Member
http://www.minkowskiinstitute.org/mip/MinkowskiFreemiumMIP2012.pdf
On page 50 of this document you will find in Minkowski's own words:
"
Thus the essence of this postulate can be expressed mathematically very concisely in the mystical formula:
3 · 10^5 km <speed of light distance covered in 1 second> = √−1 seconds <time in seconds>
"
This is his error.
Because if (light travel distance) / (light travel time) = time, THEN it naturally follows if time = 0, then light travel distance = 0. Time is not proportional to the invariant speed of light or any other velocity all the way down to an instant of time. Describing it in this manner eliminates simultanaeity altogether, because simultanaeity MEANS that t = 0, doesn't it?
So that if time stops <=0>, then so does the propagation of light, which in utter nonsense IN ANY INERTIAL REFERENCE FRAME, including that of the photon, or an observer traveling at 0.9999999,,, x c.
Minkowski used his interval (which you will find on the same page):
o demonstrate both the ideas that in this universe, NO TWO EVENTS ARE EVER SIMULTANEOUS, and also that A 4D ROTATION IS RESPONSIBLE FOR LENGTH CONTRACTION. Both ideas are not based on bindings to reality, are completely wrong, and betray his obsession with playing around with inappropriate geometry and quadratics to relate space and time in ways they were never meant to be, Basically this is the only math the man actually knew, and he knew even less physics, if that is possible.
This is no reflection on E=mc^2 or any of Einstein's excellent work, which was based almost entirely on Newton.
Both of these ideas (simultanaeity and 4D rotation) are utter nonsense, founded in nothing more profound than his first division by zero.
Entanglement is the basis of time. Entanglement spin flips happen faster "slower" than the speed of light in a vacuum can traverse the same space ONCE THE DISTANCE BETWEEN THE TWO ENTANGLED PHOTONS HAS BEEN BRIDGED BY A PROPAGATING BEAM OF ENTANGLED PHOTONS. In essence, Minkowski has ruled out the physics associated with spooky action at a distance, EVEN THOUGH this effect does not violate Special Relativity, an invariant speed of light, or even the edict that nothing travels faster "slower" than the speed of light.
Faster/slower is also relative. Minkowski evidently understood this, which I discovered while reading it. That much is amazing, but dividing by zero to make his spacetime intervals work was not cool at all. Neither is being an OCD obsessed nutjob about quadratics AND CONIC SECTIONS / LIGHT CONES, which this paper of his demonstrates better than any other he ever wrote.
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