Questions tagged [carrier-particles]

Use for force carrier particles, quanta of characteristic quantum fields, usually gauge fields, such as the quanta of electromagnetic fields (photons), of the electroweak interactions (EW bosons), and of the strong interactions (gluons); elastic forces on on a lattice (phonons); nuclear forces (pions); gravity forces (gravitons), etc. May include conjectural particles from GUTS (like their proton-decay-inducing gauge bosons).

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Why quantum gravity can't be described by spin-1 bosons? [duplicate]

As the title suggests, why quantum gravity can't be described by spin-1 gravitons?
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How does energy/momentum/information transferred to carriers?

The forces , interaction , momentum , information , etc . are transferred through carriers like photons . However , how do the carriers themselves get momentum, information and interactions ? What ...
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Is there some mathematical or physical model that postulates that gravitons exist? [duplicate]

Is there some model, mathematical or physical, that postulates that gravitons exist? For example is there mass missing from some particle decay that is thought to form gravitons? Or something in the ...
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What makes a photon a photon?

As i understand photons are excitation of the electromagnetic field. Therefore charged particles are affected by this excitation. But what if we have (highly theoretically) a particle that has the ...
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Attractiveness of Coulomb potential from Peskin-Schroeder textbook

On page 125 chapter 4.8 of Peskin & Schroeder "An Introduction To Quantum Field Theory" there's a sort of argument that should prove that in the non-relativistic limit of QED like ...
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How can I see mathematically with Feynman rules of QED that same charges repel and opposite charges attract?

I'm trying to 'prove' that electrons repel each other and electrons-positrons attract each other, but I'm not sure what I should be looking at. My guess is that there should be a different sign when ...
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How is it possible for $W$-boson to be so heavy when neutron and proton have similar mass? [duplicate]

I know that in a beta decay a neutron turns into a proton and a $W$-boson. I know that a $W$-boson is very heavy, so I intuitively expect the proton to by much lighter than neutron — I would expect ...
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Does the existence of exchange particles imply that that the 4 fundamental forces are delivered in discrete packets instead of continuously?

If exchange particles transfer the fundamental forces and these particles takes some amount of time to transfer this force does this mean there is a rate of force? (Side question: if two oppositely ...
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Gravitational Waves and Quantum Gravity [duplicate]

Since we can now directly observe gravitational wave signals, can any type of future experiment be set up that might manifest the quantum nature of gravity? For example, perhaps a version of LIGO ...
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Fundamental-ness of fundamental forces

Example : Consider a black hole and it's event horizon of radius R surrounding it . Suppose in the direction of a diameter of the black hole ( or event horizon) , there are two charged particles. ...
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Virtual photons

Is it true what is said about photons that carry electromagnetic force or field? are they virtual photons too? Where exist real photons? I don't understand the concept of virtual photon, in ...
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Does discovery of graviton disprove wormhole since latter is applicable in GR only?

I know graviton is only a hypothetical particle invented probably to serve as a placeholder in standard model, but suppose one day we discovered graviton, does this disprove the existence of wormhole ...
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Would Gravitons have Gravity in it of themselves?

If you held a handful of gravitons, would you be holding a handful of gravity, drawing things towards it, or do gravitons have to be exchanged or transmitted for gravity to take effect, in which case, ...
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How do Gravitons work? as compared to photons

Photons are to Electrons as Gravitons are to ... what? What is it that 'emits' a graviton? And what 'absorbs' it? I've been looking for a good layman's description of how gravitons interact with ... ...
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How does existence of graviton helps explain 2 different objects fall at the same rate?

Actually I want to see how gravitons help to explain why a feather and a bowling ball would fall at the same rate towards the ground assuming no air resistance, I would imagine bowling ball to emit ...
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How do gravitons escape each other's gravity to spread out and form a field?

The hypothetical graviton I'm familiar with is a spin-2 particle. That implies it has angular momentum, which further implies it has energy. If energy attracts energy, what prevents gravitons from ...
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Understanding attractive Feynman diagram [duplicate]

I’m curious about the origins of the positive/negative charge and why there might be the two, and only the two, electric charges. I saw a great example just now which I think was referencing a Feynman ...
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Mathematically, what is a graviton?

There are numerous questions on this site asking what a graviton is, but almost all the answers are superficial. I am hoping for a more formal answer. All I know in the here and now, is that it has ...
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A question on the electrostrong force

I understand that the strong nuclear force is carried by gluons, the electromagnetic force is carried by photons and the weak nuclear force is carried by the $W$ and $Z$ bosons. However, in the ...
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Protons and QED

I have been researching quantum electrodynamics recently and I have found out that when electrons repel each other, they constantly exchange photons with each other. When two protons repel, do they ...
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Would there be a force carrier particle in the unified field theory?

So from what I understand, each fundamental force (with the exception of gravity unless you count the hypothetical graviton) has a force carrier particle that mediates the force. Does that mean if the ...
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Is there such a thing as graviton temperature?

Are there purely gravitational degrees of freedom, and is there such a thing as a graviton temperature?
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What are gravitons made of? And how do they cause gravity? [closed]

What are gravitons made of and how do they cause gravity? Why do bodies with more mass attract more gravitons and hence have a greater gravitational pull? I heard that nobody quite exactly knows this (...
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Does the weak force get transmitted at speeds less than $c$?

The force carrier of EM is the photon (or off-shell photons at least). These are massless field disturbances. However the force carriers in Weak interactions are the $W$ and $Z$ bosons. Having mass, ...
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If the exchange of virtual Gravitons isn't real why do bodies attract?

I have been told Earth is not really sending particles to me and keeping me on the ground. That it is just a convenient thing to do in calculations. However if the exchange of gravitons isn't real, ...
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What does "propagate" mean in QFT?

Studying QFT, one finds the term "the field propagates" and I'm not sure I understand what it means. For example, in QED, one finds that $A_0$ "doesn't propagate" because its ...
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How do Gravitons work?

Gravitons are supposed to mediate the force of gravity, but wouldn't that require Earth, Sun and basically everything else is constantly sending out gravitons to everything else?
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Does quantum gravity contradict general relativity? [duplicate]

As far as I know, quantum gravity basically says that the graviton mediates the force of gravity. And general relativity says that gravitation is the result of masses warping spacetime, and thus ...
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What is really going on when two natural magnets repel each other?

I was listening to Frank Wilczek talking about how the electromagnetic force is actually a field, which is mediated by photons. What is our current/deepest understanding of what is happening when two ...
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Why do we take the quantization of forces so seriously even though the particles mediating the forces are not even real particles as per our theories?

Recently I came across this question on this site, where the answer written by @AndrewSteane says (paraphrased for convenience) The electromagnetic interactions between two particles can be ...
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Gravitational non-scattering [closed]

When gravitation is modelled after real life, there is no such thing as a gravitational shadow. Does this mean that gravitons travel through matter without being scattered?
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What is the physical nature of a "force"?

This has application to E-M as well as gravity, but let me use the gravitational example as I think it's a bit more conceptually easy to grasp. Say we have two 1kg weights placed on the ground a metre ...
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How are gravitons compatible with general relativity?

I have been reading about how gravity has 2 equivalents descriptions: General Relativity. Explained by the graviton. How are these two things compatible? How can it be that gravity is explained ...
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Gravitons and general relativity

First I want to say that I am a layperson, so I want intuitive answers. So all the 3 fundamental forces in nature has a carrier particle except gravity. So we have hypothesized the existence of ...
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Can you have quantum gravity without gravitons? [duplicate]

I was thinking about whether quantum gravity needs gravitons. One can do a sum over histories of curved spaces perhaps without having to have gravitons. But the term "quantization" implies ...
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How do bosons cause two particles to attract, why doesn't the exchange always result in repulsion?

If forces are mediated by the exchange of bosons, and bosons travel out from their "parent" fermion, wouldn't they be carrying momentum which pushes anything that absorbs them away from the &...
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Deriving approximate wave function of virtual photons in a simplified model of momentum transfer [duplicate]

In the virtual particles FAQ here https://math.ucr.edu/home/baez/physics/Quantum/virtual_particles.html, under "How can they be responsible for attractive forces?" I didn't follow this step: ...
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Why is the carrier diffusion neglected as a consequence of a greater penetration depth of the photoexcitation light?

"Since the diffusion lengths are considerably smaller than the penetration depth of the photoexcitation light (...), we can neglect carrier diffusion from our considerations" - THz article ...
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Number of intrinsic charge carriers in semiconductors

On one hand, my book calls both electrons and holes intrinsic charge carriers of a semiconductor, and on the other, it states the relation x = y = n, where x, y and n stand for the number of electrons,...
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Question about Weinberg-Witten theorem

From Weinberg-Witten theorem, people say that the graviton (which has spin 2) can not be composite. But it seems that graviton can still be composite particle by combining spin-3/2 particles. Is ...
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Why must there always exist a real particle with the same mass of the virtual particle of a certain force field?

I've tried to ask this question before, but I've never quite got a satisfying answer so I'm going to simplify my question. As I understand it, virtual particles are just 'internal legs of a Feynman ...
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Can a composite boson like the pion be an exchange particle for the strong nuclear force?

Hi I have been trying to understand the standard model of particle physics and I don't understand why my textbooks says that the fundamental bosons are the exchange particles of the four fundamental ...
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How the idea of force-carrying particles acts in real-world?

The idea of "force-carrying particles" is insane to me. Because if I hold two magnets near each other, probably zillionths of photons are constantly being exchanged bwteen them. In extreme ...
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Attractive Feynman diagrams and virtual photons [duplicate]

In the electromagnetic interaction a photon is exchanged which can cause a repulsive force between to charged particles like the electron/electron or up/up quarks interactions. But when i look at the ...
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Do the strong and weak nuclear forces also travel at the speed of light?

Among the four fundamental forces, it is now pretty well-known that the electromagnetic and gravitational ones travel at the speed of light. How about the other two (strong and weak nuclear forces)? ...
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Why are we searching for graviton? [duplicate]

I am computer scientist and not a physicist, but I really like physics One question popped into my mind recently about gravity. General theory of relativity describes gravity not as a force but as a ...
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Probability of breaking a covalent bond through collisions

I was watching a lecture and at some point they say that for a covalent bond of 1.1 eV and for particles with 0.026 eV mean energy, the number of particles requiered to break the bond is 42, that is 1....
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How to calculate (or do we observe) range of exchange particles in QFT?

In this question Can hydrogen atom exchange induce attractional forces between $e^-e^-$? one answer showed the range of exchange particle but not how to calculate. how do we calculate/know what are ...
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Should gravitational waves quantize similar to photons?

A single photon's energy is given by $E=hf$. This is also generalized to massive particles as $\lambda = \frac{h}{p}$ or $E = \sqrt{m_0^2c^4 + (hc/\lambda)^2}$ (they're equivalent for photons). Having ...
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Why is "Gravity as a result of space-time curvature" not accepted as a fact? [duplicate]

Now that gravitational waves are confirmed. Not to mention the other numerous experimental verifications. Why do we still need an elusive graviton? Isn't there not enough evidence that the space-time ...