Incredibly huge inconsistency of modern physics

Ziggurat said:
No, he's not mixing up reference frames, the issue is more subtle than that.

Take a reference frame (call it frame A) where a hunk of diamond is motionless. Send a photon through the diamond from left to right. As it passes through the diamond, its average velocity will be 0.4 c to the right.

Now switch to a reference frame (frame B) where the diamond is moving to the left at 0.4 c. The average velocity of that photon, while it's inside the diamond, will be 0 in reference frame B.

The trick is that "average" is not the same as "instantaneous".
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I will also point out that the speed of a wave is not always the same as the speed of the waves quanta.

One example would be a standing wave. A traveling wave has a specific speed (actually, several) that is determined by the frequency and wavelength of that wave. The speed of the quantum (i.e., particle) associated with that wave is sometimes associated with the speed of each anti-node. I haven't found the technical name for the speed of the node, but that is the speed most nonscientists would associate with the speed of a wave.

A standing wave can be made using the same frequency and wavelength. Each node in the standing wave has a speed of zero. However, the speed of the associated particle is still the speed of the standing wave.

This runs into problems of phase velocity, group velocity, energy velocity and signal velocity. Under the conditions of Ehrenfests theorem, the velocity of the particles is the group velocity. However, the group velocity is the same for standing waves and traveling waves. Sometimes all three velocities are different.

So really, the assumption made by the OP is not always valid. The photon does not necessarily move at 'c', the velocity of light in a vacuum. Furthermore, the photon does not have to always move in the same direction as the 'light wave'.


If the wavelength of the light wave is well defined as in a collimated and monochromatic plane wave, then the position of the photon is completely uncertain. Under this condition, the photon doesn't have a well defined 'speed' at all.

Einstein's 1905 article where he presented special relativity (SR) was not about photons. When he says light, he means classical electromagnetic waves in a vacuum. The motion of photons is a bit more complicated. Quantum mechanics had not been formulated yet. So bringing in photons when talking about Einstein's 1905 article is a bit misleading.

The local speed of light in a vacuum that Einstein was talking about is the phase velocity of the electromagnetic wave in a vacuum. However, photon-polariton of a certain energy in diamond won't have the same phase velocity as a photon of the same energy which exists in a vacuum.

Special relativity and quantum mechanics do not contradict each other. However, putting them together is tricky. So you have to be very careful about the word 'photon' when you talk about relativity. Better to talk about pulses of light than photons. At least when you talk about pulses of light, physicists know you are talking about wave packets. Photons are not always wave packets.

Combining general relativity and quantum mechanics is at present impossible. So I think one should be even more careful about the word 'graviton'.
 
wogoga in #130 said:
The refractive index of our vitreous humor n = 1.336. Propagation speed c/n is therefore around 224,400 km/s. If such a vitreous humor moves to the left at 224,400 km/s, and a photon in it moves to the right, then according to SR, the photon is at rest. See: Fizeau_experiment#Derivation_in_special_relativity. With a diamond (n = 2.42) a speed of roughly 40% of c would be enough to produce a photon at rest.
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Ziggurat in #137 said:
No. According to QED, a photon traveling through a material with n>1 will take a curved path on the microscopic level. In a reference frame where the macroscopic velocity of light has been reduced to zero, what this essentially means is that the light is moving in a circle, but it's still moving, and still moving at c.
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You assume here that a photon takes "a curved path" at speed c, circling around a point moving at v = c/n in a frame at rest, or circling around a point which is at rest in a frame co-moving at v = c/n. Your ad-hoc-hypothesis is only a further attempt to explain away the empirical fact of a propagation speed less than c. The necessity to replace the empirical propagation speed c/n by a 'theoretical' speed c only stems from the ineffective concept 'invariant mass' (and related dogmas).

In post #100 I have shown that in case of propagation at v = c/n in diamond, this revisionist mass concept leads to an 'invariant' photon-mass of 91% of the relativistic mass, if we believe in Abraham's momentum, and even in an imaginary value if we believe in Minkowski's momentum.

The assumption that photons are always moving at c rescues the 'massless-ness' of photons in action. If photons are assumed to move only in direction of propagation with phase conservation, then they must rest from time to time. Thus, if a pulse of 100 photons of visible light enters a diamond, the pulse is reduced to around 40 photons in action with no 'invariant mass', whereas around 60 'photons' are sleepers adding invariant mass to their sleeping spots. (As even the 'massless' non-sleeping photons contribute 'invariant mass' to the diamond, one has to conclude that "invariant mass is in general not an additive quantity"WP).

Your ad-hoc-hypothesis of photons taking "a curved path" at speed c near a center of propagation moving at c/n resolves the problem of sleeping photons. Photons never rest, only regularly change directions. In order to change direction a photon can exchange momentum with the atoms of the diamond. But how on earth can a photon keep track of all these momentum changes on microscopic level so that momentum remains unchanged on macroscopic level?

Eventually, all such problems stem from the elimination of the concept instantaneous-action-at-a-distance from physics. Then complicated reincarnations of theological concepts (such as virtual particles with properties attributed in past only to gosts, angels and so on) were introduced in order to explain what previously had been explained in a simple and transparent way by Newton, Coulomb, Ampère and others.
And based on instantaneous-action-at-a-distance, common sense (i.e. reasoning in the tradition of natural science as opposed to theology) must not be given up in order to explain emission and absorption of photons. When a photon emerges, energy from a region much smaller than spatial extension of the photon is transferred more or less instantaneously to the whole photon. Atoms 'eat' and 'excrete' photons whose wavelengths are several orders of magnitude longer than their own radiuses.

Any quantum concept remains a theological concept, as long as simple quantitative questions cannot be answered, such as e.g.:

  • How many virtual photons are involved in a force of 1 Newton between two electrically charged spheres?
  • How many times does a photon change from sleeping to in-action (or change direction in case of the always-in-action hypothesis)?
Cheers, Wolfgang
 
wogoga said:
You assume here that a photon takes "a curved path" at speed c
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I'm not assuming that. That's a standard quantum electrodymanics result. You can try to argue that quantum electrodynamics is wrong, but good luck with that.

Your ad-hoc-hypothesis of photons taking "a curved path" at speed c near a center of propagation moving at c/n resolves the problem of sleeping photons. Photons never rest, only regularly change directions. In order to change direction a photon can exchange momentum with the atoms of the diamond. But how on earth can a photon keep track of all these momentum changes on microscopic level so that momentum remains unchanged on macroscopic level?
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Momentum remains unchanged on the macroscopic level only if the photons exit the diamond at the same angle that they entered the diamond. And that only happens if the entry plane and exit plane are parallel. That's what allows the coordination of momentum transfer.

[*]How many virtual photons are involved in a force of 1 Newton between two electrically charged spheres?
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You can take the Fourier transform of a static electric field, basically breaking it down into a superposition of photons. But why would you? The answer won't mean anything useful.

[*]How many times does a photon change from sleeping to in-action (or change direction in case of the always-in-action hypothesis)?
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How many times does the earth change direction in its orbit around the sun?

It's a stupid question. The process is continuous.
 
wogoga said:
In post #100 I have shown that in case of propagation at v = c/n in diamond, this revisionist mass concept leads to an 'invariant' photon-mass of 91% of the relativistic mass, if we believe in Abraham's momentum, and even in an imaginary value if we believe in Minkowski's momentum....
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Which is obviously wrong, wogoga. The relativistic mass of a photon depends on its momentum. Change the momentum and the relativistic mass changes. The lower momentum in diamond that you use leads to a lower relativistic mass is standard, expected and even trivial physics :eek:!

Ranting about "revisionist" hides an actual dilemma in physics: the Abraham–Minkowski controversy
Two equations exist describing momentum transfer between matter and electromagnetic fields.[1] Both seem to be supported by contradictory experimental data. The two existing equations were first suggested by Hermann Minkowski (1908)[2] and Max Abraham (1909),[3][4] from which the controversy name derives.
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The Minkowski equation has a lower photon momentum in dielectric media.
The Abraham equation has a higher photon momentum in dielectric media.

wogoga said:
The assumption that photons are always moving at c ...
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Does not exist, wogoga. SR has a postulate that "light in vacuum propagates with the speed c (a fixed constant, independent of direction) in at least one system of inertial coordinates (the "stationary system"), regardless of the state of motion of the light source.".
 
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Mass-Energy is a conserved quantity, and so is Momentum-Energy. a massless particle, like a photon, 'just exists'. Accept it like that. It doesn't matter
that it happens to have zero mass, which is then of course automatically conserved. Its energy however can be given by the equation for momentum-energy and just
plugging in zero as the mass. E^2 = P^2c^2 + m^2c^4 --> E = Pc. Too bad that there wasn't any way to use the Maxwell equations to calculate the momentum from the frequency.
It requires probability distribution mechanisms called Quantum Mechanics, and beyond that there's only fruitless attempts to define pure chance. Chaos.
 
Correct up to "E = Pc", TheAdversary.
However:
Maxwell equations by themselves cannot be used to calculate momentum.
Probability distribution mechanisms are called probability distribution mechanisms!
Quantum Mechanics is a theory whose solutions include probability distributions, e.g. electron orbitals.
 
TheAdversary said:
Mass-Energy is a conserved quantity, and so is Momentum-Energy. a massless particle, like a photon, 'just exists'. Accept it like that. It doesn't matter
that it happens to have zero mass, which is then of course automatically conserved. Its energy however can be given by the equation for momentum-energy and just
plugging in zero as the mass. E^2 = P^2c^2 + m^2c^4 --> E = Pc. Too bad that there wasn't any way to use the Maxwell equations to calculate the momentum from the frequency.
It requires probability distribution mechanisms called Quantum Mechanics, and beyond that there's only fruitless attempts to define pure chance. Chaos.
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The amplitude determines total energy, not the frequency, according to both Maxwells equations and quantum electrodynamics. The frequency does not determine the total energy of a wave. The frequency only determines the energy of a single photon. Electromagnetic waves can carry far more than one photon.

Total energy and momenta in a specific volume are not calculated from the frequency using Maxwells equations. Total energy and momenta in a specific volume are calculated from the distribution of amplitudes among frequencies and wave vectors.

The amplitude determines the total energy. Amplitude is not intrinsically statistical. If one has a monochromatic wave collimated in a specific direction, then the total power of that wave per unit area (intensity) is determined by the amplitude not the frequency.

The photon represents only a fraction of the total energy and momentum. The energy and momentum of the photon is determined by frequency and wave vector. However, the photons are distributed statistically.

The photon only exists in quantum mechanics, or quantum electrodynamics. The amplitude determines the total number of photons, so the amplitude determines the total energy, even in quantum mechanics.
 
I'm talking about a single photon. Energy and momentum are related to frequency/wavelength via the de Broglie hypothesis. The absolute square of the amplitude forms a
probability distribution function which when integrated over an interval gives you the probability of measuring the photon in that interval. So if the probability is higher,
you'll detect more photons, all of which have an energy and momentum determined by the frequency/wavelenght.
What I'm saying is that we already had a very nice theory of light, the Maxwell equations, that led to the discovery of the Lorenz transform, the essence of Relativity,
but we couldn't use it to complete the Relativistic theory of light, since the treatment of 'particles' requires a probability distribution function methodology.
And after that, just pure chance remains and nothing soever can be said about that. This is unfortunate if you'd like physics to be completely closed.
 
You see? It doesn't make sense to talk about it in terms of particles. Measurements and conservation of probability only. Anything else leads to the fallacious notion of
attempting to reason about pure chance. Shut up and calculate!
 
TheAdversary said:
You see? It doesn't make sense to talk about it in terms of particles. Measurements and conservation of probability only. Anything else leads to the fallacious notion of
attempting to reason about pure chance. Shut up and calculate!
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Tell me more... This conservation of probability thingy sounds so scientific, but seems a little thin.
 
Feynman used the more colourful expression 'so that particles don't 'get lost'', if I remember correctly. If probability isn't conserved, particles disappear or
come out of nowhere.
 
TheAdversary said:
I'm talking about a single photon. Energy and momentum are related to frequency/wavelength via the de Broglie hypothesis. The absolute square of the amplitude forms a
probability distribution function .....
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Sorry, TheAdversary, but the promising start of your post declines into non-science.
The de Broglie hypothesis is that all particles can be assigned a wavelength related to its momentum. It is a simple equation with no connection to probability.

You may be confusing de Broglie "waves" with the wave function of QM. For wave functions, the "absolute square of the amplitude forms a probability distribution function"
In the Copenhagen interpretation, an interpretation of quantum mechanics, the squared modulus of the wave function, |ψ|2, is a real number interpreted as the probability density of measuring a particle as being at a given place at a given time or having a definite momentum, and possibly having definite values for discrete degrees of freedom.
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Are you seriously maintaining that the de Broglie wave isn't Quantum Mechanical? And its interpretation has nothing to do with probability? I thought that's what the
early days of QM where all about! Learning that those new 'waves' were different from the classical waves. What wavelength are you talking about then?

And conservation of probability obviously has to be maintained as a base axiom. That should be obvious even if you know nothing about QM.
The theory will then state that stuff can disappears or come out of nowhere. That's just nonsense.
 
I can think of waves in a pool, electromagnetic radiation, or quantum mechanical 'particle waves'. The latter is required for us to have a model of a photon at all,
if I'm not mistaken. I'm seriously interested in where the wavelength to calculate the momentum comes from then.
 
TheAdversary said:
Are you seriously maintaining that the de Broglie wave isn't Quantum Mechanical?
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I am telling you the science, TheAdversary.
  • There is no such thing as a " de Broglie wave". There is no actual wave just the assignment of a wavelength to the momentum of particles. Particles get "wave-like" properties. Particles do not become waves.
  • This is the de Broglie equation and has nothing to do with probability.
  • Where "waves" appear in QM is the wave function which is not the de Broglie equation.
  • There are many interpretations of QM.
    Some of these interpretations are deterministic, i.e. no probability distribution functions.
  • One interpretation of QM is the Copenhagen interpretation where the wave function
    In the Copenhagen interpretation, an interpretation of quantum mechanics, the squared modulus of the wave function, |ψ|2, is a real number interpreted as the probability density of measuring a particle as being at a given place at a given time or having a definite momentum, and possibly having definite values for discrete degrees of freedom.
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Repeating an idea about "conservation of probability" does not make it less a fantasy, TheAdversary :eye-poppi! Citations to the scientific literature about "conservation of probability" would make it less a fantasy. A coherent or better a mathematical definition of "conservation of probability" would make it less a fantasy.

Repeating the logical fallacy of argument from incredibility does not make the argument valid, TheAdversary. A person not understanding virtual particles and calling them nonsense does not mean that they that they do not exist.
 
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Well, you get a continuity equation for the probability current in non-relativistic quantum mechanics. I can see calling this equation "conservation of probability." Such an equation doesn't really apply in relativistic quantum field theory, though. You have conservation (and continuity equations) for other currents, like the electromagnetic current for instance, but this conservation law holds through the creation and annihilation of particles.

For instance, a muon will decay into an electron, a muon neutrino, and an electron antineutrino. Electromagnetic current is conserved through this process. The number of each species of particle is not.

You could also call the fact that all possible outcomes have probabilities that sum together to 1 "conservation of probability," but then this wouldn't in any way entail that particles can't be created or destroyed.
 
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