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Author Topic: What is the evidence for force-carrying particles?  (Read 7992 times)

Offline PAOLO137

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Notwistanding I have read a very large number of books concerning quantum physics, I have not found a satisfactory explanation of why
forces, at the level of elementary particles, are exerted by means of "carrier particles" as e.g.  gluons between nucleons. By the way
this concept,which looks so strange to me, convinced everybody that a particle called graviton must be responsible of gravitational force.
Who and when proposed this solution to explain what Einstein used to call "spooky action at a distance"? Thanks for Your attention,Paolo de Magistris, Rome, Italy.
« Last Edit: 11/11/2013 19:15:58 by chris »


 

Offline Pmb

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Re: Force carrying particles
« Reply #1 on: 10/11/2013 12:09:06 »
Quote from: PAOLO137
Notwistanding I have read a very large number of books concerning quantum physics, I have not found a satisfactory explanation of why forces, at the level of elementary particles, are exerted by means of "carrier particles" as e.g.  gluons between nucleons. By the way this concept, which looks so strange to me, convinced everybody that a particle called graviton must be responsible of gravitational force.
Who and when proposed this solution to explain what Einstein used to call "spooky action at a distance"?
I too wish I understood that. I e-mailed an acquaintance of mine who knows the answer to that question. Until I hear back from him I want to let you know that this has nothing to do with what Einstein was referring to when he used the phrase spooky action at a distance Einstein used that when describing his dismay at the prospect of entangled particles. Two such particles can be separated by distances large enough for light not to reach one from the other when an observation of one particle immediately determines the state of the other particle.
 

Offline PAOLO137

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Re: What is the evidence for force-carrying particles?
« Reply #2 on: 13/11/2013 18:28:43 »
You are right. I'm sorry for having quoted a sentence which has nothing to do with those particles responsible of carrying the force.
If you don't mind, I would like to share with somebody the following impression : All the explanatory books for the common man, report a kind
of historical tale about the years from 1900 to 1930. Very interesting with al the debates and anectodes repeated in every book, like the love adventures of Shrodinger or the hay fever of Heisenberg. Then, suddenly, the history ends, and we are trown in the world of Feynman and Gell-man
without any explication of the steps that bring to the necessity of a Higgs boson. Is it only my impression, or these writers think the recent developments
not so interesting or credible? I would be interested to know your opinion. With my best regards, Paolo.
 

Offline jeffreyH

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Re: What is the evidence for force-carrying particles?
« Reply #3 on: 13/11/2013 19:11:54 »
You are right. I'm sorry for having quoted a sentence which has nothing to do with those particles responsible of carrying the force.
If you don't mind, I would like to share with somebody the following impression : All the explanatory books for the common man, report a kind
of historical tale about the years from 1900 to 1930. Very interesting with al the debates and anectodes repeated in every book, like the love adventures of Shrodinger or the hay fever of Heisenberg. Then, suddenly, the history ends, and we are trown in the world of Feynman and Gell-man
without any explication of the steps that bring to the necessity of a Higgs boson. Is it only my impression, or these writers think the recent developments
not so interesting or credible? I would be interested to know your opinion. With my best regards, Paolo.

The search for gravitational waves is underway but because the force is weak it is thought these will only be found by examining large compressed objects such as black holes. What perplexes me is the fact that we can detect electromagnetic waves and know that the photon is the carrier but not gravitation. If it is so hard to detect such a particle as the graviton then maybe that is because it does not exist. Spacetime curvature is thought to be responsible so maybe it is simply the effect of mass on the spacetime containing it that causes the effect and the momentum induced by compression is the driving force.
 

Offline yor_on

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Re: What is the evidence for force-carrying particles?
« Reply #4 on: 18/11/2013 01:16:45 »
There are historical papers, and I think I linked one at least, some time before? It was of German origin I think (Max Planck institute?) and described the almost feverish time when Quantum mechanics first started to bear fruit, and the 'competition' between theorists and experimentalists, as experimentalists was more interested in validating existing theory than creating new, whereas a theorist was free to soar. I'll see if I can find it, but I agree. It's not that much history about those first years on the internet.
 

Offline yor_on

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Re: What is the evidence for force-carrying particles?
« Reply #5 on: 18/11/2013 01:28:49 »
Try http://www.edition-open-access.de/proceedings/5/index.html

It's a free book over QM history. Not what I linked the first time, but it seems interesting and made in the same spirit.

"More than a century after the beginning of the quantum revolution, historians continue to explore new facets in the history of quantum physics, and to re-examine some of its better-known aspects. The thirteen papers collected in this volume, by authors from five continents, present central trends in the current study of quantum physics within its theoretical, experimental, philosophical, technological and social contexts. They discuss developments from the late nineteenth to the early twenty-first century and go beyond the traditional focus on Europe and North America to include China and Japan, and beyond the Heisenbergs and Diracs to reveal the role of actors who hitherto have played only a marginal role in historical account, but left their mark on the development of quantum physics. Also a wider array of subdisciplines comes into view, from optics to quantum gravity through quantum electrodynamics, from atomic and nuclear to condense matter physics and foundations of physics. Moreover, the volume shows that fields such as dispersion, physical chemistry and solid state physics should not be seen merely as areas of applications of ideas that evolved in other contexts, but should be regarded as birthplaces of important theoretical insights. The perspective of the papers ranges from local histories to global discussions, from conceptual changes via the role of experimentation to interactions with social and technological forces and to the interpretation of the theory."
 

Offline JP

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Re: What is the evidence for force-carrying particles?
« Reply #6 on: 18/11/2013 18:22:58 »
The early QM of Heisenberg and Schrodinger dealt with what's termed the first quantization, in which one describes particles in terms of quantum mechanics, but fields such as the electric field are still classical, meaning continuous and divisible into infinitesimally small parts. 

There was then a lot of work (much of the pioneering work by Dirac) on how to quantize fields.  In other words, how to describe fields in terms of their smallest constituent parts rather than treating them as classical. 

Joining this together with the concept of particles led to being able to describe interactions between particle in quantum terms.  Classically, two electrons interacting would do so via a classical electromagnetic field.  In quantum mechanics, the electromagnetic field is quantized, so the field connecting these two particles has smallest "bits" to it, which can be described as particles.  It does get much more complex than that, but that's the basic idea.
 

Offline Bill S

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Re: What is the evidence for force-carrying particles?
« Reply #7 on: 18/11/2013 19:07:43 »
Gravity is one of those things that I find puzzling.  It is not a force.  Deutsch, and many other authors make that quite clear.

David Deutsch (1998) argues that there is no gravitational force.  “In the nineteenth century, few things would have been regarded more confidently as real than the force of gravity.  Not only did it figure in Newton’s then-unrivalled system of laws, but everyone could feel it, all the time, even with their eyes shut – or so they thought.  Today we understand gravity through Einstein’s theory rather than Newton’s, and we know that no such force exists.  We do not feel it!  What we feel is the resistance that prevents us from penetrating the solid ground beneath our feet.  Nothing is pulling us downwards.  The only reason why we fall downwards when unsupported is the fabric of space and time in which we exist is curved.”

However, Gribbin (1996) says – along with other authors – that “Gravity is the weakest of the four forces of nature”.

If it is not a force, how can it me mediated by a graviton? 

If it is a force, why are we told it is not?
 

Offline JP

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Re: What is the evidence for force-carrying particles?
« Reply #8 on: 18/11/2013 19:58:52 »
It really depends on what you mean when you say force.  Like so many concepts that we can all agree on in Newtonian physics, the concept of force has to be refined when you go to relativistic physics.  In Newtonian physics, objects move in straight lines unless acted upon by a force.  Those forces include gravity.  In general relativity, objects move on geodesics (the generalization of a straight line) unless acted upon by a non-gravitational force.  So in that sense, gravity just redefines "straight line" and doesn't behave like a Newtonian force. 

However, Newtonian forces act in flat (Cartesian) space and an independent time dimension, while gravity in general relativity is described by the curvature of space-time.  In this sense, the fact that the geodesic isn't a straight line is due to gravity.  So gravity is deviating straight lines. 

I haven't done a poll, but gravity is still taught as a force in most textbooks, and I suspect that most physicists would say that it is a force, but seems to be very unlike the other forces in having its properties bound up in space-time.
 

Offline jeffreyH

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Re: What is the evidence for force-carrying particles?
« Reply #9 on: 19/11/2013 03:25:14 »
It can be argued either way. There may be a graviton or it could simply be space-time curvature. However you have to ask what causes the curvature in the first place. A densly packed mass effects space-time in such a way but in an undeterimed way. If we don't have a carrier then spooky action at a distance is nearer than we think. If space-time and matter are inseparable then the curvature itself could be inherant and produced by states of matter. We may have to look at the relationship between matter and space-time in a different way. They may not be two individual entities.
 

Offline acsinuk

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Re: What is the evidence for force-carrying particles?
« Reply #10 on: 19/11/2013 17:19:55 »
I don't think it is either gravitons or curvature of space.
When it comes to molecules the inside particles are surely all electric; so the forces will also be electric. To force 2 similarly charged particles together requires a 10^38G strong nuclear force but as the protons and neutrons [which are touching the electron enclosure] are both magnetised upwards or the same way they repel each other with a10^36G force which is greater than the 10^25G electro-weak force. The 1G gravity is insignificant.
CliveS
 

Offline jeffreyH

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Re: What is the evidence for force-carrying particles?
« Reply #11 on: 20/11/2013 04:57:58 »
I don't think it is either gravitons or curvature of space.
When it comes to molecules the inside particles are surely all electric; so the forces will also be electric. To force 2 similarly charged particles together requires a 10^38G strong nuclear force but as the protons and neutrons [which are touching the electron enclosure] are both magnetised upwards or the same way they repel each other with a10^36G force which is greater than the 10^25G electro-weak force. The 1G gravity is insignificant.
CliveS

Interesting. So do you believe that gravitation is an inherent property of matter.
 

Offline PAOLO137

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Re: What is the evidence for force-carrying particles?
« Reply #12 on: 27/11/2013 18:22:34 »
I feel very happy noting how many have read and (in many cases) posted a comment on my original question. My difficulties in figuring out
how forces are made up of particles jumping back and forth between the (how may I call them?) real particles. Let's perform the following
simple experiment : an electron is travelling along a straight line in space, when it meets a space volume between two parallel metal plates
charged with opposite sign charges (a classical field, I used to think). The path of the electron becomes parabolic. Why? Because a kind of shower of photons is "raining" like cats and dogs in that volume. Do I see it correctly? Thanks,Paolo.
 

Offline yor_on

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Re: What is the evidence for force-carrying particles?
« Reply #13 on: 28/04/2014 20:50:18 »
hah, I don't care if anyone reads it, they should!!!
 

Offline acsinuk

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Re: What is the evidence for force-carrying particles?
« Reply #14 on: 06/05/2014 09:30:56 »
Jeffrey
"Interesting. So do you believe that gravitation is an inherent property of matter."

Although gravity is an insignificant force it is absolutely essential as a matter volume enclosure has the ability to absorb 3D light and heat as a magnetic vibration that stops moving at the speed EM light and just becomes EM heat.
BTW  Correction to my last post the neurton and electron shell inside a molecule are magnetised upwards and protons downways so their 2 north poles push each other apart at 10^36G which is greater than the 10^25G charge attraction.
CliveS
 

Offline McKay

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Re: What is the evidence for force-carrying particles?
« Reply #15 on: 06/05/2014 11:35:14 »
I don't think it is either gravitons or curvature of space.
When it comes to molecules the inside particles are surely all electric; so the forces will also be electric. To force 2 similarly charged particles together requires a 10^38G strong nuclear force but as the protons and neutrons [which are touching the electron enclosure] are both magnetised upwards or the same way they repel each other with a10^36G force which is greater than the 10^25G electro-weak force. The 1G gravity is insignificant.
CliveS
h
It can be argued either way. There may be a graviton or it could simply be space-time curvature. However you have to ask what causes the curvature in the first place. A densly packed mass effects space-time in such a way but in an undeterimed way. If we don't have a carrier then spooky action at a distance is nearer than we think. If space-time and matter are inseparable then the curvature itself could be inherant and produced by states of matter. We may have to look at the relationship between matter and space-time in a different way. They may not be two individual entities.
yes, perhaps mass IS the curvature. It doesnt cause space tu curve. The curvature is mass.
 

Offline jeffreyH

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Re: What is the evidence for force-carrying particles?
« Reply #16 on: 06/05/2014 19:11:49 »
I don't think it is either gravitons or curvature of space.
When it comes to molecules the inside particles are surely all electric; so the forces will also be electric. To force 2 similarly charged particles together requires a 10^38G strong nuclear force but as the protons and neutrons [which are touching the electron enclosure] are both magnetised upwards or the same way they repel each other with a10^36G force which is greater than the 10^25G electro-weak force. The 1G gravity is insignificant.
CliveS
h
It can be argued either way. There may be a graviton or it could simply be space-time curvature. However you have to ask what causes the curvature in the first place. A densly packed mass effects space-time in such a way but in an undeterimed way. If we don't have a carrier then spooky action at a distance is nearer than we think. If space-time and matter are inseparable then the curvature itself could be inherant and produced by states of matter. We may have to look at the relationship between matter and space-time in a different way. They may not be two individual entities.
yes, perhaps mass IS the curvature. It doesnt cause space tu curve. The curvature is mass.

You could argue it is just a curved length contraction of the mass.
 

Offline mxplxxx

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Re: What is the evidence for force-carrying particles?
« Reply #17 on: 23/05/2014 03:57:13 »
The best evidence for bosons (force-carrying particles) is to be found in the cloud chambers associated with colliders. The standard model of physics predicts the existence of families of particles and the results from the collision of high energy protons in colliders like the Large Hadron Collider back up the theory. Gluons are not directly detected, but certain events in the cloud chamber indicate something like a gluon is involved in the events. The Higgs boson which was predicted by the standard model has recently been verified in the LHC. A book, the Particle at The End of the Universe by Sean Carroll is a fabulous reference for answering your question. Sean is one of many modern writers who are making physics more and more accessible to non-mathematicians.
 

Offline jeffreyH

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Re: What is the evidence for force-carrying particles?
« Reply #18 on: 23/05/2014 22:42:36 »
Jeffrey
"Interesting. So do you believe that gravitation is an inherent property of matter."

Although gravity is an insignificant force it is absolutely essential as a matter volume enclosure has the ability to absorb 3D light and heat as a magnetic vibration that stops moving at the speed EM light and just becomes EM heat.
BTW  Correction to my last post the neurton and electron shell inside a molecule are magnetised upwards and protons downways so their 2 north poles push each other apart at 10^36G which is greater than the 10^25G charge attraction.
CliveS

That implies that an unknown force holds solid matter and even atoms together. Maybe something linked to colour change. Maybe gravitation, both or they are intimately related.
 

Offline evan_au

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Re: What is the evidence for force-carrying particles?
« Reply #19 on: 24/05/2014 11:38:17 »
Quote from: jeffreyH
There may be a graviton or it could simply be space-time curvature.
I am interested in how space-time curvature alone can explain the behaviour of binary pulsars.
  • These are seen to have a gradually decreasing orbital period.
  • In Newton's theory of gravity, this can be explained by the mass of the pulsars increasing, which increases the attractive force between them
  • In space-time curvature of gravity, this can be explained by the mass of the pulsars increasing, which increases the curvature of space, so the geodesic is more tightly curved in 3-Space.
  • But the explanation which won the 1993 Nobel Prize in Physics originates with General Relativity: some of the energy and momentum of the orbiting pulsars is not remaining within the system, but is being radiated out of the system by ripples in the gravitational field, which propagate away from the system at the speed of light. We call these ripples "gravitons". 
This discovery is regarded as indirect evidence for the existence of gravitational waves, which are coherent waves of gravitons.
 

Offline acsinuk

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Re: What is the evidence for force-carrying particles?
« Reply #20 on: 24/05/2014 12:05:21 »
Jeffrey
The unknown force is the electromagnetic force which is massless so there is no point in looking for a particle.  The strong nuclear and weak electrostatic may in some ways be mass related though.
CliveS
 

Offline jeffreyH

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Re: What is the evidence for force-carrying particles?
« Reply #21 on: 26/05/2014 06:13:18 »
Quote from: jeffreyH
There may be a graviton or it could simply be space-time curvature.
I am interested in how space-time curvature alone can explain the behaviour of binary pulsars.
  • These are seen to have a gradually decreasing orbital period.
  • In Newton's theory of gravity, this can be explained by the mass of the pulsars increasing, which increases the attractive force between them
  • In space-time curvature of gravity, this can be explained by the mass of the pulsars increasing, which increases the curvature of space, so the geodesic is more tightly curved in 3-Space.
  • But the explanation which won the 1993 Nobel Prize in Physics originates with General Relativity: some of the energy and momentum of the orbiting pulsars is not remaining within the system, but is being radiated out of the system by ripples in the gravitational field, which propagate away from the system at the speed of light. We call these ripples "gravitons". 
This discovery is regarded as indirect evidence for the existence of gravitational waves, which are coherent waves of gravitons.

I was working on field density equations for gravitons before I got too busy. The loss via radiation would be at the surface of the object and limited. Gravitational energy loss would be much like the radiation of photons from the sun, being mainly contained within the solid mass. Light and heat may take millions of years to escape. This gravitational loss would be partly counter-balanced by the much smaller absorption of gravitation from external sources. Due to field scattering this re-absorption would be very low compared to gravitational loss from the mass itself. Angular momentum would be gradually lost along with gravitational mass-energy. To me the proton and neutron are the best candidates for graviton emission and should be linked to the gluon via some unknown mechanism.
 

Offline jeffreyH

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Re: What is the evidence for force-carrying particles?
« Reply #22 on: 26/05/2014 07:21:25 »
One article I happened upon was this.

http://arxiv.org/abs/1206.5078

Here not only is an attempt made to include dark matter and dark energy into relativity but the field density with radial distance plays an important part. This reflects my own thinking on the field density but they raise some other interesting points such as two Higgs particles and a spin 1 dark energy boson.
 

Offline acsinuk

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Re: What is the evidence for force-carrying particles?
« Reply #23 on: 05/06/2014 10:06:09 »
The statement Φ in the gravity momentum equation needs to be explained. Is this similar to the rate of cutting of flux refered to in Faradays ElectroMotiveForce equation  e=-NdΦ/dt which also defines a force in space in terms of curling voltage difference during a circumference length movement of that force?
CliveS
 

Offline jeffreyH

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Re: What is the evidence for force-carrying particles?
« Reply #24 on: 08/06/2014 23:09:07 »
The best evidence for bosons (force-carrying particles) is to be found in the cloud chambers associated with colliders. The standard model of physics predicts the existence of families of particles and the results from the collision of high energy protons in colliders like the Large Hadron Collider back up the theory. Gluons are not directly detected, but certain events in the cloud chamber indicate something like a gluon is involved in the events. The Higgs boson which was predicted by the standard model has recently been verified in the LHC. A book, the Particle at The End of the Universe by Sean Carroll is a fabulous reference for answering your question. Sean is one of many modern writers who are making physics more and more accessible to non-mathematicians.

I wish more people would take the trouble to read up on the early history of the development of the standard model. A lot of wild speculation would then be reduced. It is fascinating and shows the steps leading to the recognition of the bosons as force carriers. The story of the development of the various colliders and the steps in energy levels required shows just how difficult this was.
 

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Re: What is the evidence for force-carrying particles?
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