No.Would it confirm Bohmian Mechanics?
No.Would it confirm Bohmian Mechanics?
Yes.
Wave functions are used to describe the quantum states of entities with mass. A wave function does not "have" a mass, as it is a description of a quantum state of an entity which has mass as one of its properties. It is the entity that has the mass, not the wave function. Photons, being massless, do not have a wave function, or not in the sense that Schrödinger developed it: https://physics.stackexchange.com/q...describes-the-wavefunction-of-a-single-photonYes.
AFAIK, a wave function has no mass. So tell me, how could a particle be a massless wave?
Now what? Going to close this thread? That will be enlightening!
According to the article, photons do have mass, albeit extremely small.Wave functions are used to describe the quantum states of entities with mass.
But does a photon in transit not act as a wave? Is the double slit experiment not about wave interference of photons.A wave function does not "have" a mass, as it is a description of a quantum state of an entity which has mass as one of its properties.
I understand that, but the article claims that photons do have mass. And that makes all the difference, no?It is the entity that has the mass, not the wave function. Photons, being massless, do not have a wave function, or not in the sense that Schrödinger developed it: https://physics.stackexchange.com/q...describes-the-wavefunction-of-a-single-photon
In Bohmian mechanics a system of particles is described in part by its wave function, evolving, as usual, according to Schrödinger’s equation. However, the wave function provides only a partial description of the system. This description is completed by the specification of the actual positions of the particles. The latter evolve according to the “guiding equation”, which expresses the velocities of the particles in terms of the wave function. Thus, in Bohmian mechanics the configuration of a system of particles evolves via a deterministic motion choreographed by the wave function. In particular, when a particle is sent into a two-slit apparatus, the slit through which it passes and its location upon arrival on the photographic plate are completely determined by its initial position and wave function.
Wrong. The article says the measurements show that if it has mass, it can only be less than 9.52 × 10⁻⁴⁶ kilograms. That result is consistent with the actual mass being zero, as theory indicates, as the article makes this clear.According to the article, photons do have mass, albeit extremely small.
No.Yes.
A wave function is a piece of mathematics. No piece of mathematics is a particle.AFAIK, a wave function has no mass. So tell me, how could a particle be a massless wave?
All the experimental evidence we have is consistent with the proposition that photons have zero rest mass. There is no reason to suspect that photons have non-zero mass, as far as I am aware.According to the article, photons do have mass, albeit extremely small.
Nobody knows. Photons are never detected "in transit".But does a photon in transit not act as a wave?
It can be about that, certainly.Is the double slit experiment not about wave interference of photons.
Does it?Hence my question about Bohmian mechanics that assumes photons to have mass...
Makes all the difference to what?I understand that, but the article claims that photons do have mass. And that makes all the difference, no?
All the experimental evidence we have is consistent with the proposition that photons have zero rest mass. There is no reason to suspect that photons have non-zero mass, as far as I am aware. It sounds like you probably misunderstood the article.
We have a new upper limit for the mass of light.
According to measurements of pulsing stars scattered throughout the Milky Way and mystery radio signals from other galaxies, a particle of light – called a photon – can be no heavier than 9.52 × 10^-46 kilograms.
It's a tiny limit, but finding that light has any mass at all would significantly impact how we interpret the Universe around us, and our understanding of physics.
However, we don't know for absolute certainty that photons are massless.
If a photon did have mass, it would need to be extremely small to not have major effects on the way the Universe appeared, which means that we just don't have the tools to measure it directly.
But we can take indirect measurements that will give us an upper limit for this hypothetical mass, and this is exactly what a group of astronomers did.
So are you saying there is no wave/particle duality as deduced from the double slit experiment?A wave function is a concept that can be used to describe certain features of real-world particles. It is particularly useful for predicting the results of real-world observations made using real-world particles.
The wave-particle duality of photons
These experiments show that while a photon was detected as having the properties of a particle, interference appeared like that of a wave while simultaneously passing through the double-slit, revealing that the photon has the dual properties of a particle and a wave. More... https://photonterrace.net/en/photon/duality/#
Here is the actual paper: https://iopscience.iop.org/article/10.3847/1538-4357/ad2f99I refer back to post #100
How Heavy Can a Particle of Light Be? Scientists Just Figured It Out
If I understand you they are not talking about anything new at all?
What a peculiar way to describe zero rest mass with an upper limit.
Perhaps they not talking about "rest" mass, but acquired mass from motion @ SOL, that cannot exceed that limit?
I could understand that.
If that upper limit was heavier than that the stated limit, it would be unable to travel @ SOL, no?
No, I did (do) not ignore your posts. I just find it very confusing to read that a photon has no rest mass, but if it does it won't exceed that quoted number.(This is what I explained to you in post 105, which you have ignored.)
That is what I posited. So, that's ok.Abstract
Exploring the concept of a massive photon has been an important area in astronomy and physics. If photons have mass, their propagation in nonvacuum space would be affected by both the nonzero mass mγ and the presence of a plasma medium.
What is meant by "deriving a dispersion relation"? Does this mean a nonzero massive photon exist or not?For the first time, we have derived the dispersion relation of a photon with a nonzero mass propagating in plasma.
What is meant by "constraining the upper bound of the photon mass"? Again, does that mean a nonzero photon exists or not?To reduce the impact of variations in the dispersion measure (DM), we employed the high-precision timing data to constrain the upper bound of the photon mass.
Here it is again "upper bound of photon mass". There seemstobea lot of confirmation of nonzero massive photons.The dedispersed pulses from fast radio bursts (FRBs) with minimal scattering effects are also used to constrain the upper bound of photon mass.
It is essential to investigate the photon's mass when they have zero mass? Can a photon acquire mass?In the future, it is essential to investigate the photon mass, as pulsar timing data are collected by PPTA and UWB receivers, or FRBs with wideband spectra are detected by UWB receivers.
I've made it as clear as I can. If you can't understand my explanation, I can't help you any further.No, I did (do) not ignore your posts. I just find it very confusing to read that a photon has no rest mass, but if it does it won't exceed that quoted number.
This the abstract from your much appreciated link.
That is what I posited. So, that's ok.
question: What about photons being affeced by the Higgs field? That's where matter acquires mass, no?
What is meant by "deriving a dispersion relation"? Does this mean a nonzero massive photon exist or not?
If not then what "derivation" was being measured?
What is meant by "constraining the upper bound of the photon mass"? Again, does that mean a nonzero photon exists or not?
Here it is again "upper bound of photon mass". There seemstobea lot of confirmation of nonzero massive photons.
It is essential to investigate the photon's mass when they have zero mass? Can a photon acquire mass?
Now we seem to have statements that we have examples of photons that do have mass under a specific circumstance ?
Am I asking the right question? If not, can anyone tell me what "in space" these folks are talking about.
I am not trying to be difficult, but this apparent contradiction intrigues me.
Quarks and lepton but not neutrinos IIRCThat is what I posited. So, that's ok.
question: What about photons being affeced by the Higgs field? That's where matter acquires mass, no?
No it means it, "cannot be any more massive than..."What is meant by "constraining the upper bound of the photon mass"? Again, does that mean a nonzero photon exists or not?
No, there is no experimental evidence for a massive photon and they have just moved the finishing line closer to zero. If a photon does have some mass then it cannot be larger than 9.5 x10-45 kg that is its upper bound.Here it is again "upper bound of photon mass". There seemstobea lot of confirmation of nonzero massive photons.
All our theories are built around the requirement that photons have zero rest mass. If they do not, we would have to completely rewrite our theories.It is essential to investigate the photon's mass when they have zero mass? Can a photon acquire mass?
Now we seem to have statements that we have examples of photons that do have mass under a specific circumstance ?
Good effort. Let’s see if the penny drops.All our theories are built around the requirement that photons have zero rest mass. If they do not, we would have to completely rewrite our theories.
But we have yet to confirm that zero mass mass experimentally.
How do you prove a zero?
Q: To how many decimal places does it have to be zero before it's zero? A: Infinitely many zeros.
So far, we have shown the rest mass of a photon to be as near to zero as 0.000 000 000 000 000 000 000 000 000 000 000 000 000 000 01kg
When we test for the mess of a photon, we can only do so to a certain degree of precision. If we can't test smaller than that, then someone could always come along and say "it's got mass, just less than you were able to measure".
So we keep testing to push that observed number down - to fifty decimal places, then sixty (note that each decimal place is ten times greater precision. So 10^-50 is 10,000 times more precise than our current observation, 10^-60 is a hundred million trillion more precise than that). We will never reach infinity.
Still, we're "pretty sure" it's zero, Since if it were not, most of our 21st century civilization would collapse around our ears.
So we keep testing to push that observed number down - to fifty decimal places, then sixty (note that each decimal place is ten times greater precision. So 10^-50 is 10,000 times more precise than our current observation, 10^-60 is a hundred million trillion more precise than that). We will never reach infinity.
Ok, I understand that, even as at first glance it appears to be conraditory .Still, we're "pretty sure" it's zero, Since if it were not, most of our 21st century civilization would collapse around our ears.
It is almost certainly impossible to do any experiment that would establish the photon rest mass to be exactly zero. The best we can hope to do is place limits on it. A non-zero rest mass would introduce a small damping factor in the inverse square Coulomb law of electrostatic forces. That means the electrostatic force would be weaker over very large distances.
The Charge Composition Explorer spacecraft was used to derive an upper limit of 6 × 10−16 eV with high certainty. This was slightly improved in 1998 by Roderic Lakes in a laboratory experiment that looked for anomalous forces on a Cavendish balance. The new limit is 7 × 10−17 eV. Studies of galactic magnetic fields suggest a much better limit of less than 3 × 10−27 eV, but there is some doubt about the validity of this method.
zero.Ok, I understand that, even as at first glance it appears to be conraditory .
From a prior paper showing "lower limits" than the current paper with the newly established "higher limit" .
What is the mass of a photon?
This question falls into two parts:
a) Does the photon have mass? After all, it has energy and energy is equivalent to mass.
b) Photons are traditionally said to be massless. This is a figure of speech that physicists use to describe something about how a photon's particle-like properties are described by the language of special relativity.
How does it appear to contradictory?Ok, I understand that, even as at first glance it appears to be conraditory .
The experiment put a new upper limit on the mass of the photon. That's new.If I understand you they are not talking about anything new at all?
It's quite standard in science to quote values with uncertainties.What a peculiar way to describe zero rest mass with an upper limit.
They are talking about rest mass. Note, however, that if the mass of the photon is actually zero, then it can never be brought to rest; if, on the other hand, it does have a minuscule mass, then it would be theoretically possible to bring it to rest.Perhaps they not talking about "rest" mass, but acquired mass from motion @ SOL, that cannot exceed that limit?
Correct, though it would still travel very close to the speed of light after being given the tiniest push.If that upper limit was heavier than that the stated limit, it would be unable to travel @ SOL, no?
In my previous reply to you, I wrote:So are you saying there is no wave/particle duality as deduced from the double slit experiment?
Our current best theory says that mass comes from the way that excitations in certain quantum fields interact with another field (the Higgs field).If there is that duality, then should the wave function not equal the mass of the particle in some way, else where does any mass at all come from?
Bohm's theory is designed to predict all the same experimental results as regular quantum mechanics. Only the suggested "mechanism" is different.OTOH, if there is only the appearance of wave/particle duality, that would suggest Bohmian mechanics, i.e. a separate "guiding pilot wave function" that carries the particle (with an acquired mass), yet answers to the Schrodinger equation.
It means doing an experiment that will give one result if the mass is larger than a certain value and a different result if the mass is larger than that value. The result, in the case of the experiment under discussion, is that the photon mass was found to be less than the quoted value that was calculated based on the parameters of the particular experiment. Hence, the experiment puts an upper bound on the photon mass.What is meant by "constraining the upper bound of the photon mass"?
There is no confirmation that any photons have had, or ever will have, any mass other than zero.There seems to be a lot of confirmation of nonzero massive photons.
We don't know that they have zero mass. All we have is a lower and an upper bound on the mass. The only way to be sure is to investigate.It is essential to investigate the photon's mass when they have zero mass?
I'm aware of no theory that predicts that photons ought to have non-zero mass. There might be one, but it would have to be incompatible with a lot of other well-verified theories. Still, some of our well-established theories have turned out to be wrong before. There's no way to know without investigating.Can a photon acquire mass?
No, we don't.Now we seem to have statements that we have examples of photons that do have mass under a specific circumstance ?