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Quantum Electrodynamics - Science topic
Explore the latest questions and answers in Quantum Electrodynamics, and find Quantum Electrodynamics experts.
Questions related to Quantum Electrodynamics
A body at rest has rest Energy, so it should also have rest Momentum.
Lao Tzu said, “Gravity is the root of lightness; stillness, the ruler of movement”(重为轻根，静为躁君)*. The meaning of this statement can be extended in physics to mean that "big-G determines how light or heavy an object is, and rest-m determines how easy or difficult it is to move".
According to the mass-energy equation** [1], E=mc^2, any object with mass m has "rest energy" [1], regardless of its inertial frame†. Note that E here is meant to be the energy lost when radiating the photon γ, which is absolute and unchangeable in any inertial frame. The mass-energy equation has been experimentally verified [2] as the correct relation.
According to special relativity [3], the mass of the same object is different in different inertial frames, m' = βm. Therefore, the energy of conversion of m of an object into photon γ is different in different inertial frames. This issue has been discussed in [4], but there is no consensus. Our view is that the "rest energy" is theoretically not Lorentz invariant, and the existence of a minimum value is a reasonable result. The most rational explanation for this is that the minimum corresponds to an absolutely static spacetime, i.e., absolute spacetime(Later we will show that absolute space-time and relative space-time are not in conflict). Analytically, this is one of the reasons why absolute spacetime should exist. The constant speed of light is another reason.
In all cases in physics, energy and momentum coexist and have a fixed relationship, not independent metrics. The energy-momentum ‡ of a photon, E=hν[5], P=h/λ[6]; the energy-momentum relation of Newtonian mechanics, E=P^2/2m; and the relativistic energy-momentum relation, E^2=c^2p^2+m^2c^4. Therefore, it is assumed that if there is a body of mass m that has "rest energy", then it should also have "rest momentum". There is a "rest momentum", and the rest momentum cannot be zero. The rest energy is not intuitive, and the rest momentum should not be intuitive too. The calculation of the rest momentum is the same as the calculation of the rest energy. The nature of mass looks more like momentum; after all, energy is a sign of time, while momentum is a sign of movement. Therefore, instead of calling it the principle of equivalence of inertial mass and rest-energy[1], it should be called the principle of equivalence of inertial mass and rest-momentum.
When positive and negative electrons meet and annihilate [7], -e+e→γ+γ, radiating two photons in opposite directions. Their energy is conserved and so is their momentum. Energy is a scalar sum, while momentum is a vector sum. It seems that the "rest momentum" inside the object should be zero. However, one could argue that it is actually the momentum of the two photons that is being carried away, but in opposite directions. The momentum of the two photons should not come out of nothing, but rather there should be momentum of the two photons, also in some balanced way, and probably playing a very important role, such as the binding force.
Our questions are:
1) Since energy and momentum cannot be separated, should an object with "rest energy" necessarily have "rest momentum".
2) Elementary particles can be equated to a " energy packet ", and energy is time dependent. If an elementary particle is also equivalent to a "momentum packet", the momentum in the packet must be related to space. Does this determine the spatio-temporal nature of the elementary particles? And since momentum is related to force, is it the force that keeps the "energy packet" from dissipating?
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Notes：
* Lao Tzu，Tao-Te-Ching，~500 BCE. This quote is a translation of someone else's. There are some excesses that I don't entirely agree with. Translating classical Chinese into modern Chinese is just as difficult as translating classical Chinese into English.
** There is a historical debate about the process of discovery of the mass-energy equation, and digging into the history shows that there were discoverers and revisers both before and after Einstein, see literature [8][9]. Important contributions came from Poincaré, F. Hasenöhrl, Planck et al. Their derivations do not have the approximation of Einstein's mass-energy equation. And there is also a debate about the interpretation of the mass-energy equation. Notable debates can be found in the literature[10].
† There is a question here, i.e., is the rest mass Lorentz invariant? That is, is the rest mass the same in different inertial systems? Why?
‡ Einstein questioningly emphasized that energy and momentum seem to be inseparable, but did not explain it.
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References：
[1] Einstein, A. (1905). "Does the inertia of a body depend upon its energy-content." Annalen der physik 18(13): 639-641.
Einstein, A. (1935). "Elementary derivation of the equivalence of mass and energy." Bulletin of the American mathematical society 41(4): 223-230.
[2] Rainville, S., J. K. Thompson, E. G. Myers, J. M. Brown, M. S. Dewey, E. G. Kessler, R. D. Deslattes, H. G. Börner, M. Jentschel, P. Mutti and D. E. Pritchard (2005). "A direct test of E=mc2." Nature 438(7071): 1096-1097.
[3] Einstein, A. (1905). "On the electrodynamics of moving bodies." Annalen der physik 17(10): 891-921.
[4] Is there a minimum value of m in the mass-energy equation E=mc^2? https://www.researchgate.net/post/NO7_Is_there_a_minimum_value_of_m_in_the_mass-energy_equation_Emc2；
[5] Planck, M. (1900). " " Verh. Deutsh. Phys. Ges 2: 237.
[6] Einstein, A. (1917). Physikalisehe Zeitschrift xviii: p.121
[7] Li, B. A. and C. N. Yang (1989). "CY Chao, Pair creation and Pair Annihilation." International Journal of Modern Physics A 4(17): 4325-4335.
[8] Ives, H. E. (1952). "Derivation of the mass-energy relation." JOSA 42(8): 540-543.
[9] Sharma, A. (0000). "The past present and future of the Mass Energy Equation DE =Dmc2." http://www.mrelativity.net/Papers/8/Sharma4.htm.
[10] Peierls, R., J. Warren and M. Nelkon (1987). "Mass and energy." Physics Bulletin 38(4): 127.
God said, "Let there be light."
So, did God need to use many means when He created light? Physically we have to ask, "Should all processes of light generation obey the same equation?" "Is this equation the 'God equation'?"
Regarding the types of "light sources", we categorize them according to "how the light is emitted" (the way it is emitted):
Type 0 - naturally existing light. This philosophical assumption is important. It is important because it is impossible to determine whether it is more essential that all light is produced by matter, or that all light exists naturally and is transformed into matter. Moreover, naturally existing light can provide us with an absolute spacetime background (free light has a constant speed of light, independent of the motion of the light source and independent of the observer, which is equivalent to an absolute reference system).
Type I - Orbital Electron Transition[1]: usually determines the characteristic spectra of the elements in the periodic table, they are the "fingerprints" of the elements; if there is human intervention, coherent optical lasers can be generated. According to the assumptions of Bohr's orbital theory, the transitions are instantaneous, there is no process, and no time is required*. Therefore, it also cannot be described using specific differential equations, but only by probabilities. However, Schrödinger believed that the wave equation could give a reasonable explanation, and that the transition was no longer an instantaneous process, but a transitional one. The wave function transitions from one stable state to another, with a "superposition of states" in between [2].
Type II - Accelerated motion of charged particles emitting light. There are various scenarios here, and it should be emphasized that theoretically they can produce light of any wavelength, infinitely short to infinitely long, and they are all photons. 1) Blackbody radiation [3][4]: produced by the thermal motion of charged particles [5], is closely dependent on the temperature, and has a continuous spectrum in terms of statistical properties. This is the most ubiquitous class of light sources, ranging from stars like the Sun to the cosmic microwave background radiation [6], all of which have the same properties. 2) Radio: the most ubiquitous example of this is the electromagnetic waves radiated from antennas of devices such as wireless broadcasting, wireless communications, and radar. 3）Synchrotron radiation[7]，e+e− → e+e−γ；the electromagnetic radiation emitted when charged particles travel in curved paths. 4）bremsstrahlung[8]，for example, e+e− → qqg → 3 jets[11]；electromagnetic radiation produced by the acceleration or especially the deceleration of a charged particle after passing through the electric and magnetic fields of a nucleus，continuous spectrum. 5）Cherenkov Radiation[9]：light produced by charged particles when they pass through an optically transparent medium at speeds greater than the speed of light in that medium.
Type III：Partical reactions、Nuclear reactions：Any physical reaction process that produces photon (boson**) output. 1）the Gamma Decay；2）Annihilation of particles and antiparticles when they meet[10]: this is a universal property of symmetric particles, the most typical physical reaction；3）Various concomitant light, such as during particle collisions；4）Transformational light output when light interacts with matter, such as Compton scattering[12].
Type IV: Various redshifts and violet shifts, changing the relative energies of light: gravitational redshift and violet shift, Doppler shift; cosmological redshift.
Type V: Virtual Photon[13][14]?
Our questions are:
Among these types of light-emitting modes, type II and type IV light-emitting obey Maxwell's equation, and the type I and type III light-emitting processes are not clearly explained.
We can not know the light-emitting process, but we can be sure that the result, the final output of photons, is the same. Can we be sure that it is a different process that produces the same photons?
Is the thing that is capable of producing light, itself light? Or at least contains elements of light, e.g., an electric field E, a magnetic field H. If there aren't any elements of light in it, then how was it created? By what means was one energy, momentum, converted into another energy hν, momentum h/λ?
There is a view that "Virtual particles are indeed real particles. Quantum theory predicts that every particle spends some time as a combination of other particles in all possible ways"[15]. What then are the actual things that can fulfill this interpretation? Can it only be energy-momentum?
We believe everything needs to be described by mathematical equations (not made-up operators). If the output of a system is the same, then the process that bridges the output should also be the same. That is, the output equations for light are the same, whether it is a transition, an accelerated moving charged particle, or an annihilation process, the difference is only in the input.
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* Schrödinger said：the theory was silent about the period s of transition or 'quantum jumps' (as one then began to call them). Since intermediary states had to remain disallowed, one could not but regard the transition as instantaneous; but on the other hand, the radiating of a coherent wave train of 3 or 4 feet length, as it can be observed in an interferometer, would use up just about the average interval between two transitions, leaving the atom no time to 'be' in those stationary states, the only ones of which the theory gave a description.
** We know the most about photons, but not so much about the nature of W, Z, and g. Their mass and confined existence is a problem. We hope to be able to discuss this in a follow-up issue.
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Links to related issues:
【1】"How does light know its speed and maintain that speed?”;
【2】"How do light and particles know that they are choosing the shortest path?”
【3】"light is always propagated with a definite velocity c which is independent of the state of motion of the emitting body.";
【4】“Are annihilation and pair production mutually inverse processes?”； https://www.researchgate.net/post/NO8_Are_annihilation_and_pair_production_mutually_inverse_processes;
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Reference:
[1] Bohr, N. (1913). "On the constitution of atoms and molecules." The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science 26(151): 1-25.
[2] Schrödinger, E. (1952). "Are there quantum jumps? Part I." The British Journal for the Philosophy of science 3.10 (1952): 109-123.
[3] Gearhart, C. A. (2002). "Planck, the Quantum, and the Historians." Physics in perspective 4(2): 170-215.
[4] Jain, P. and L. Sharma (1998). "The Physics of blackbody radiation: A review." Journal of Applied Science in Southern Africa 4: 80-101. 【GR@Pushpendra K. Jain】
[5] Arons, A. B. and M. Peppard (1965). "Einstein's Proposal of the Photon Concept—a Translation of the Annalen der Physik Paper of 1905." American Journal of Physics 33(5): 367-374.
[6] PROGRAM, P. "PLANCK PROGRAM."
[8] 韧致辐射；
[9] Neutrino detection by Cherenkov radiation：" Super-Kamiokande(超级神冈)." from https://www-sk.icrr.u-tokyo.ac.jp/en/sk/about/. 江门中微子实验 "The Jiangmen Underground Neutrino Observatory (JUNO)." from http://juno.ihep.cas.cn/.
[10] Li, B. A. and C. N. Yang (1989). "CY Chao, Pair creation and Pair Annihilation." International Journal of Modern Physics A 4(17): 4325-4335.
[11] Schmitz, W. (2019). Particles, Fields and Forces, Springer.
[12] Compton, A. H. (1923). "The Spectrum of Scattered X-Rays." Physical Review 22(5): 409-413.
[13] Manoukian, E. B. (2020). Transition Amplitudes and the Meaning of Virtual Particles. 100 Years of Fundamental Theoretical Physics in the Palm of Your Hand: Integrated Technical Treatment. E. B. Manoukian. Cham, Springer International Publishing: 169-175.
[14] Jaeger, G. (2021). "Exchange Forces in Particle Physics." Foundations of Physics 51(1): 13.
[15] Are virtual particles really constantly popping in and out of existence? Or are they merely a mathematical bookkeeping device for quantum mechanics? - Scientific American.
Two similar charges repulse one another. if the charges are separated by 'sheet' of parallel moving photons, (the velocity of photon is normal to straight line connecting two charges, and polarization of electric field is normal to both photon motion and similar-change joining straingth line. Thus, the moving away or coming together of those similar charges are not at all effected by photons, if only velocity component of the charges facing one another is concerned. Clearly, magnetic field of photons would be parallel to straight line joining these two charges, but this would not also affect aforementioned velocity components of the charge). So, semi-classically, the moving away of the charged particles, that is their repulsion, would not be affected. also assume the media is vacuum, so no polarization of material media is occuring. Of course, all the photons are required to be palne-polarized and collimeted.
However, accroding to QFT, charged particles exchange photon (virtual?) that is manifested as attraction-repulsion between them. These exchaning photons are surely to collide with real photon stream, get deflected, and hence would no longer be captured by other charged particle. Thus the net force between the two charged particles would no longer be same.
Now my question is, is there any experiment to verify this claim of QED? Or real and virtual particles of same kind would not interact at all? Or the same charge is effective force is also explainable from lorentz force as the charged particles oscillate noremal to their connecting straight line due to electric field, and then magnetic field acts to retard?
(THIS IS A THOUGHT EXPERIMENT, so whether this situation is generatable by present technological means is immaterial. What matters is whether the setup is allowed by laws of Physics on Not. Parallel photon shower can be generated by allowing collimited photons (e.g. by Lens and Laser) to have a light-spot cross-section of a very narrow rectangle or very long slit )
Dear Sirs,
I did not find an answer to this question in Internet for both quasi-relativistic and relativistic case. I would be grateful if you give any article references.
As I think the answer may be yes due to the following simplest consideration. Suppose for simplicity we have a quasi relativistic particle, say electron or even W boson - carrier of weak interaction. Let us suppose we can approximately describe the particle state by Schrodinger equation for sufficiently low velocity of particle comparing to light velocity. A virtual particle has the following properties. An energy and momentum of virtual particle do not satisfy the well known relativistic energy-momentum relation E^2=m^2*c^4+p^2*c^2. It may be explained by that an energy and a momentum of the virtual particle can change their values according to the uncertainty relation for momentum and position and to the uncertainty relation for energy and time. Moreover because of the fact that the virtual particle energy value is limited by the uncertainty relation we can not observe the virtual particle in the experiment (experimental error will be more or equal to the virtual particle energy).
In the Everett's multi-worlds interpretation a wave function is not a probability, it is a real field existing at any time instant. Therefore wave function of wave packet of W boson really exists in the Universe. So real quasi relativistic W boson can be simultaneously located in many different space points, has simultaneously many different momentum and energy values. One sees that a difference between real W boson and virtual W boson is absent.
Is the above oversimplified consideration correct? Is it possible to make any conclusion for ultra relativistic virtual particle? I would be grateful to hear your advises.
Using -e^2/(Re-Rp) potential in Shrodinger equation for hydrogen atom means that proton and electron are point particles. Why do we think, that on atomic size they are point-like? Just guess, that give exact spectrum?
I hope there is someone out there with a solid grasp of renormalization in quantum electrodynamics that can answer this question. It bothers me that the integrals that arise from loop Feynman diagrams involve a limit of infinite energy of virtual particles. But, according to the uncertainty principle a particle with infinite energy has a zero lifetime. It appears this consideration is not taken into account in these integrals. The position 4-vector integrals in the S matrix terms, evaluated before the 4-momentum integrals, are taken over all space and time. So how can the 4-momentum integrals take the uncertainty principle into account?
Earth has a North Pole and a South Pole. Is this a paradigm or a model that we need to understand before we can begin to understand the structural (or some other) design of the universe? If so, point to one other example of polarity. If not, why not?
Hi guys, Maybe someone can tell me about the current state of interpreting sonoluminescence as dynamical Casimir effect? Recently I came across two older theoretical papers from the 90s on this topic. One paper (actually as series) is from Julian Schwinger with the title "Casimir light", the other paper is from Claudia Eberlein "Sonoluminescence as Quantum Vacuum Radiation".
If I understand correctly, these papers say that the rapidly changing bubble wall converts virtual photons, which constitute the field of the cavity as quantum electrodynamic vacuum, into the real ones. However, it is shown that there is significant deviation between the theoretical expectation and experimental observation.
So, are there any new experiments or new theoretical calculations after the 90s on this topic? Thanks a looooot!
Let's assume that states |1> and |2> are degenerate states and the system is prepared in state |1>. Also, the matrix element of electric dipole moment is not zero between these two states (<1|mu|2>=!0). If we interact this system with vacuum field, does this system remain in its initial state? (I know from Wigner Weisskopf theory that if these two levels were not degenerate and level |1> was the excited state, the system would decay with Einstein rate.)
It is known that high energy gamma photons can decay into electron-positron pairs in a strong background field via the multi-photon Breit-Wheeler process. This real photon is first emitted by an energetic electron, therefore this is a two-step process. There exist also one-step process, where the intermediate photon is virtual, thus one electron can directly create the pair in a strong laser field. For the trident production rate I found formulas in the literature, which is implemented in EPOCH for instance, but in the code the energy of newly created particles is zero. In the case of two-step process it is clear that the total energy of pair is equal to the photon energy, but I could not find any clear expression for this initial energy in the case of trident. I think it is assumed that their initial momentum is relatively small and their recoil effect is negligible, that's why it is approximated by zero in order to reduce the computation in PIC codes. However, I could not find any paper supporting this statement. Can someone help me in this ?
The recoil force of radiation is known for spontaneous emission (for the radiation of an accelerating charge or dipole), when the photon field is empty. Is there any difference when stimulated emission is considered? Would it be enough to add an external force to the original radiative reaction-force without changing the original form of the radiative reaction?
I'm trying to learn more about the Purcell effect and specifically how it relates to surface enhanced raman scattering (SERS).
The Purcell effect, or 'modified spontaneous emission' occurs when 'a dipolar atomic transition couples to the vacuum state of the electromagnetic field' (Le Ru and Etchegoin arXiv 2005).
This transition becomes more likely when the local electric field is made stronger, for instance due to the excitation of a surface plasmon.
I believe that the strength of the coupling between the atomic transition and the electromagnetic field depends on the strength of the local electric field. However, I don't have enough background in quantum electrodynamics to really understand why this is.
Why does the local electric field magnitude affect the emission rate (and emitted power) of an emitter?
How can I obtain the DM DM -> SM SM annihilation cross section if the DM effective operator is given? It would be really helpful if someone can show me the detail derivation.
There is formula relating power radiated and acceleration of charged particle. But i want to know the amount of energy is carried by the photon at a particular time by given acceleration by using relativistic quantum electrodynamics.
I saw in a paper that the current in a metal is sigma (conductivity=e*mu*n) multiplied by dk/dx where k is the electrochemical energy (or fermi energy).
It seems to me that it is some kind of a generalized ohm's law (j=sigma*E) where the electric field is 1/e*dk/dx.
My questions are these:
# Is it truely a generalized ohm's law or is it comes from other more fundamental law?
# Is this law valid for semiconductors and/or outside equilibrium (steady state, external applied voltage)?
# I couldn't find anything on this equation and I'll be grateful if someone could direct me to some books referring this equation.
As generally stated that quantum mechanics is the wider theory and it contains classical theory as a special case. We can get classical results from its quantum counter part in the limit of planck constant tends to zero. Can we get classical maxwell electrodynamics as a similar limiting case from quantum electrodynamics?.
Just read "Inflation and the Measurement Problem". If I understand correctly, they proposed a model with interaction between Fourier modes. By tuning parameter one will obtain Harrison-Zel’dovich scale-invariant
power-spectrum as well as Gaussian Random field. What I don't understand is that I think it still need measurement to form a classical field configuration. Did I misunderstand it?
Thanks for answering.
In an exercise* I have to verfy that if qmu is the momentum carried by a gauge boson in QED vertex with an incoming particle and an outgoing particle both being on-shell, then q2 < 0.
*Palash B. Pal
For a Vector Boson DM, I have the following spin-independent direct detection (scattering) cross-section with nucleus (please see the attahced file), where n_n and n_p are the number of nucleons inside the nucleus and f_p, f_n are the effective nucleon-DM coupling, M_T is the mass of target nucleus and M is the DM mass. How do I convert it to per nucleon cross-section, what will be the final expression? Thank you.
When electrons stabilize on atoms' orbitals, unreleasable adiabatic energy is induced in excess of the invariant energy corresponding to their rest mass. For example, an unreleasable amount of 27.2 eV is induced at the hydrogen atom rest orbital in excess of the energy corresponding to the rest mass of the electron, which is an energy not necessarily associated to a velocity, meaning that no momentum may be involved if the electron finds itself translationally immobilized, even if this energy in excess of the rest mass energy remains induced.
I did some research and found this ref. by James Montaldi 2014 (First ref. below).
In the Montaldi paper, the following topics are addressed:
Section 3.1 Zero momentum, non-zero velocity.
Section 3.2 Zero momentum, zero velocity.
Section Zero momentum, zero velocity was the one that should have covered the case, except that it assumes that ξ=0, which, unless I do not understand correctly, does not cover the case of the adiabatic energy induced in orbitals EM equilibrium states.
This makes me observe that the Hamiltonian as formulated, seems to deal only with translational momentum, and doesn't seem to be able to represent zero momentum zero velocity with energy>0, or am I missing something?
I would like input on how this case is being addressed from the electromagnetism perspective.
Adiabatic energy induction is analyzed in the second ref.
Scattering of light by matter has been studied extensively in the past. Yet, the most fundamental process, the scattering of a single photon by a single atom, is largely unexplored. One prominent prediction of quantum optics is the deterministic absorption of a travelling photon by a single atom, provided the photon waveform matches spatially and temporally the time-reversed version of a spontaneously emitted photon.
Here we experimentally address this prediction and investigate the influence of the photon’s temporal profile on the scattering dynamics using a single trapped atom and heralded single photons. We don't often think of photons as being spread out in time and space and thus having a shape, but the ones in this experiment were some four meters long. Christian Kurtsiefer, Principal Investigator at CQT, and his team have learned to shape these photons with extreme precision.
According to the quantum mechanics that photon is an unstructured particle. How the concept of unstructured photon is able to describe the different shapes and four meter long of photon?
In addition to four meters long and shapes of photons, how two opposites’ charged particles such as electron and positron absorb and emit neutral and unstructured photons?
However, in CPH theory photons are combination of positive and negative virtual photons. Photon is a very weak electric dipole that is consistent with the experience and these articles are asserted. In addition, this property of photon (very weak electric dipole) can describe the absorption and emission energy by charged particles.
Update Oct 18: Attached is now a description enhanced by equations and graphs.
The attached text (about 1.3 pages) describes a paradox which seems to have no solution in classical physics. Two solutions in the framework of quantum mechanics are outlined.
Do you think a classical solution is possible? If so, could you please provide a sketch of your solution? If not, what do you think about the suggested QM solutions, and do you know of a better (resp. the true) solution? And finally, this might be a well known paradox; if so, could you please point me to relevant literature?
Many thanks for all helpful comments in advance!
This post is an off-shoot of another post in RG. https://www.researchgate.net/post/If_a_charge_falls_freely_in_the_earths_gravitational_field_does_it_radiate
I am putting this separately outlining the key aspects of it.
Radiation by an excited atom is a well established quantum phenomenon. Typically, additional energy could be supplied by multiple means such as lasers etc. Electrons jump to the higher excited states which are often unstable and so, electrons decay back to the previous configuration by emitting the excess energy as radiation.
Now consider what most books put it bluntly regarding electrodynamics of charges in motion: "An accelerated charge radiates like a dipole." My queries are:
1) Let a charged atom be in accelerated motion. Then one can account for development of fields from the notion of retarded and Lienard-Wiechert potential. However, how does this motion triggers the necessary electronic excitation required for radiation? Or, is it that radiation mechanism from an accelerated charge is not related to the electronic excitation at all?
2) Let there be an isolated charge (electrons, protons) in accelerated motion in empty space. The acceleration could be due to some initial kick (accelerator system) OR could be due to following a trajectory in curved space-time arising as a result of some gravitational potential. If the particle radiates, then by mass-energy equivalence they lose energy and finally fade out in space? True?
It is known that Yang-Mills theory is part of classical field theory. Therefore it seems possible to write down SU(2) electrodynamics. What do you think? Your comments are welcome.
See our new paper: Exploration of a SU(2) Electrodynamics Based on Lehnert’s Revised Quantum Electrodynamics.
Many mysteries and set of behaviors are based on particle and wave functions of energy. Here are few questions which might get raised for more deep down understanding and future applications of natural phenomenon in favor of man controlled technology.
0. Energy adopted wave and particle function in one go, or its inborn or its result of evolution and what will happen if any of both get seize or get some other basic behavioral function? anyhow what any-other behavioral function can be?
01 Is there any transitional, intermediate (stable) sage between particle & wave function?
1. What is wave function and Mass function for energy?
2. What are the specific set of (structural & functional parameters / properties of) wave behavior and particle behavior?
3. Do mass and particle is the same entity?
4. Do wave and field are the same entity?
5. Is there any particle without wave function?
6. Can particle survive without wave fields etc?
7. Any particle can have permanency as particle all the time?
8. If yes then how and if NO then why?
9. Any set of conditions in which any particle can exists in “spore formation” and shred some of its basic behaviors but still sustain as particle?
10. Any wave/field which could have permanency as wave/field all the time?
11. Any set of conditions in which Wave can act like a particle without transforming into particle structure?
These questions are initially for basic elementary particle, subatomic particles specifically for Electron and Photon…("Do all particles have wave function like photons ?")…. But any brainstorming is more than welcome for man-made theoretical/particle particles as well.
Thanks
Recently I wrote a paper discussing possibility to develop Quantum Electrodynamics in Fractal Media and Cantor Sets based on Bo Lehnert's Revised Quantum Electrodynamics. Enclosed is my paper.
I admit that my approach is very rough, but at least I found some interesting things.
What do you think? Your comments are welcome. Thanks
(I already solved the problem by setting the keyboard to US English, I explain a message below)
I'm trying to use SpekCalc to simulate a X ray tube, but apprently it's not showing the bremsstrahlung radiation. I´m using a peak energy of 100keV, a theta of 16 degrees, and 5 milimeters of aluminium. But I obtain the same results whatever I have tried. I'm runing release 1.1 light for macOS, and I obtained the same results for windows.
Note: I'm using the values Nf=2 and p=1, instead of those suggested by Poludniowski because apparently the GUI is not accepting any value minor than 1.0. I have been trying other values with similar results.
I have tried the same steps but did not face the error which you specified (see attached image).
Quantum field theory comes from starting with a theory of fields, and applying the rules of quantum mechanics. A field is simply a mathematical object that is defined by its value at every point in space and time.
Renormalization, that astounding mathematical trick that enabled one to tame divergences in Feynman diagrams, led to the triumph of quantum electrodynamics. Ken Wilson made it physics, by uncovering its deep connection with scale transformations.
According to Relativity, mass and energy are convertible to each other. According to F=-dU/dx, does force (in fact bosons) and energy convert to each other? If so, by which mechanism? If no, why?
Article Unified Force, Energy and Mass
The Nobel Prize in Physics 1965 was awarded jointly to Sin-Itiro Tomonaga, Julian Schwinger and Richard P. Feynman "for their fundamental work in quantum electrodynamics, with deep-ploughing consequences for the physics of elementary particles".
QED rests on the idea that charged particles (e.g., electrons and positrons) interact by emitting and absorbing photons, the particles that transmit electromagnetic forces. These photons are “virtual”; that is, they cannot be seen or detected in any way because their existence violates the conservation of energy and momentum.
In quantum electrodynamics (QED) a charged particle emits exchange force particles continuously. This process has no effect on the properties of a charged particle such as its mass and charge. How is it describable?
A single photon state can be generated by pulsed excitation from an optical transition between two energy levels in a single quantum system such as QD. I am trying to find a way of generating indistinguishable photon pairs from say two or more sources using QFC. Any one with an idea on this can give some advice.
By the 1950s, when Yang–Mills theory, also known as non-abelian gauge
theory, was discovered, it was already known that Quantum Electrodynamics (QED) gives an extremely accurate account of electromagnetic fields and forces. So it was natural to inquire whether non-abelian gauge theory described other forces in nature, notably the weak force and the strong or nuclear force. The massless nature of classical Yang–Mills waves was a
serious obstacle to applying Yang–Mills theory to the other forces, for the weak and nuclear forces are short range and many of the particles are massive. Hence these phenomena did not appear to be associated with long-range fields describing massless particles. In the 1960s and 1970s, physicists overcame these obstacles to the physical interpretation of non-abelian gauge theory. In the case of the weak force, this was accomplished by the Glashow–Salam– Weinberg electroweak theory. By elaborating the theory with an additional “Higgs field,” one avoided the massless nature of classical Yang–Mills waves. The solution to the problem of massless Yang–Mills fields for the strong interactions has a completely different nature. That
solution did not come from adding fields to Yang–Mills theory, but by discovering a remarkable property of the quantum Yang–Mills theory itself, called “asymptotic freedom”.Asymptotic freedom, together with other experimental and theoretical discoveries made in the 1960s and 1970s involving the symmetries and high-energy behaviour of the strong
interactions, made it possible to describe the nuclear force by a non-abelian gauge theory in which the gauge group is G = SU(3). The non-abelian gauge theory of the strong force is called Quantum Chromodynamics (QCD). But classical non-abelian gauge theory is very different from the observed world of strong interactions; for QCD to describe the strong force successfully, it must have at the quantum level the mass-gap and related color confinement
properties. Both experiment—since QCD has numerous successes in confrontation with experiment—and computer simulations carried out since the late 1970s, have given strong encouragement that QCD does have the properties of mass-gap and color confinement cited above. But they are not fully understood theoretically. In the attached link, http://dx.doi.org/10.13140/RG.2.1.1637.3205 the theoretical understanding of mass-gap and related color confinement property have been provided during mathematical calculation of the gluon emission cross section for QCD process by taking over the corresponding results from closely related aforesaid QED process under the assumption that color interactions in perturbative sector are “a copy of electromagnetic interactions.
As such, the direct mathematical calculation for QCD process has been
avoided because the presence of point-like Dirac particles inside hadrons through Bjorken scaling and the carriage of a substantial portion of proton’s momentum by neutral partons, as revealed by the ‘asymptotic freedom’ based analysis of the data on deep inelastic scattering of leptons by nucleons, do not constitute direct evidence that the aforesaid Dirac particles and neutral partons can be identified with quarks and gluons respectively for making QCD the correct physical theory.
- When antiparticles annihilate, all the energy from matter, EM, strong, weak and Higgs fields bound to the particles converts to a pair of photons, involving only EM energy. Across the moment of conversion, the gravitational field is unchanged. (It may of course be changing beforehand or afterward as a result of the motion of the particles or photons and the changing quadrupole moment)
- When a photon decays (in the presence of a suitable momentum absorber) into a particle-antiparticle pair, the reverse happens. Again, there is no immediate change in the gravitational field.
In the case of a binary star system radiating gravitational waves, does the mass of the binary system decrease? Or does it just exchange potential for kinetic energy as the stars revolve faster in their reduced orbit?
If the former, is the process reversible, can gravitational waves carry energy which then converts to kinetic, EM, matter (rest), strong, weak or Higgs energy?
This is not something you can find clearly stated.
If photon is a particle then it should be not applicable, but in the double slit experiment a photon interferes with itself. But if this is the case it must be propagating in all directions but it clearly doesn't.
In the article "tunnel ionization of complex atoms and of atomic ions in an alternating electromagnetic field" (ADK ionization model) it is written in the introduction section that the conditions hbar*omega<<Ei and E<<Eatom permit the use of the quasiclassical approximation, where omega and E are the frequency and amplitude of the laser field respectively and Ei & Eatom are the ionization energy and atomic field strength respectively. In the second section it is written that the quasiclassical approximation is valid when the condition n*>>1 is satisfied, where n* is the effective principal quantum number which is defined in the article as Z/(2Ei)^(1/2) where Z is the ion charge after the ionization process.
My question is how the condition n*>>1 leads to the conditions hbar*omega<<Ei and E<<Eatom and to the quasiclassical approximation?
For example, a water molecule (H2O) in its vapor state has an electric dipole moment of magnitude 6.2*10^-30 C.m.
How much work must an external agent do to rotate this molecule by 180°, starting from its current position, for which theta= 0?
What do you think about the below calculations?
The work done by an external agent (by means of a torque applied to the molecule) is equal to the change in the molecule’s potential energy due to the change in orientation.
Wa= U180 - U0
=(-pE cos 180) - (-pE cos 0)
= 2pE = (2)(6.2*10^30 C.m)
= 1.24*10^-29 J
I know that if we solve the Maxwell equation, we will end up with the phase velocity of light being related to the permeability and the permittivity of the material. But this is not what I'm interested in - I want to go deeper than that. We know that the real speed of light is actually not changing, the decrease in speed is just apparent. Material is mostly empty, the light will still travel with c in the spacing. The rare atoms will disturb the light in some way. So I am interested in how the atoms affect the light.
Photon absorption-emission theory
Some textbooks that I read explain it in a way kind of like this:
In a material the photons are absorbed by atom and then re-emitted a short time later, then they travel a short distance to the next atom and get absorbed&emitted again and so on. How quickly the atoms in a material can absorb and re-emit the photon and how dense the atoms decides the apparent speed of light in that material. So the light appears slower because it has a smaller “drift speed”.
Interference theory
But recently I realize an alternative explanation:
Atoms respond to the light by radiating electromagnetic wave. This “new light” interferes with the “old light” in some way that results in delayed light (advanced in phase), this can easily be shown by using simple phasor diagram. Consequently effectively the light covers a smaller phase each second, which gives the impression of a lower phase velocity. However the group velocity is changing in a complicated way.
I think that the first explanation does not explain the change in phase velocity of light. if we consider light travelling into a slab of negative refractive index non-dispersive material, let’s say the light is directed perpendicular to the slab. The phase velocity’s direction will be flipped, but group velocity’s direction in the material will not change. Only the second explanation can explain the flipped phase velocity direction. I guess that the velocity that we get in the first explanation is actually belongs to the group velocity. It makes sense to me that the front most of the photon stream determines the first information that the light delivers.
So the question is What really cause the phase velocity of light to be decreased?
"drift velocity" of photons (they aren't the same photons, they are re-emitted all the time)
phase difference between absorbed and emitted light
something else
And also, I still don't really understand detailed explanation of the absorption-emission process for small light's wavelength (for large lambda compare to the atoms spacing, the photons will be absorbed by the phonons). The dispersion relation that we know is continuous and also some material is non-dispersive, therefore the absorption process must occur in all frequency for a certain range. So definitely it doesn't involve the atomic transition, otherwise it will be quantized. My guess is that the relevant absorption process gets smooth out by the dipole moment. What makes the spectrum continuous?
I am trying to conceptually connect the two formulations of quantum mechanics.
The phase space formulation deals with Wigner quasi-probability distributions on the phase space and the path integral formulation usually deals with a sum-over-paths in the configuration space.
I see how they both lead to non-classical physics but how do they relate? Either conceptually or formally.
The thing that motivates me is the idea that the Lagrangian, via the action, is a map from the tangent bundle of the configuration space to the reals. The Wigner function is a map from the cotangent bundle (phase space) of the configuration space to the reals. To get expectation values out both W(x,p) and eS(x,v) act as weightings in an integral (S=action, W=Wigner function). I would like to get from one to the other without using Hilbert space as an intermediary.
Quantum field theory tries to reduce the fields to particles (bosons) which interact with their sources (fermions) transferring energy and momentum, if we restrict to electrodynamics. In the case of the weak or strong nuclear interactions the gluons carry also color or flavour, that we can forget for the moment ,without entering in this question dtirectly, given its complexity.
Considering only electrodynamics then, we know that a magnetic field cannot give energy to a free electron, while the electric does. Could we understand this different physical behaviour using a Feynman diagrams or the concept of photon-electron interaction instead of the field? How could we understand the change of "magnetic photons" by "electric ones" using the Faraday or Ampere's law?
we know there are different systems to generate squeezing of light. But I want to know:-
1) which one is the best system and how much squeezing we can get at it's maximum and minimum value?
2) What are the different applications of squeezing of light?
as we all know that skyrmion or vortex domain wall is a real-space berry phase，but In ferromagnet/heavy metal bilayers, an in-plane current gives rise to spin-orbit spin transfer torque where spin-orbit coupling has a mometun-space berry phase if we use this current to induce domain wall, what will happen?
Everyone who is familiar with classical electrodynamics knows about Lorentz invariant quantities (E2 - B2) and (E*B).
Is there any application for these invariants in physics?
The interaction of photons with matter such as Compton and Thompson scattering are well-known at higher photon energies. What about the scattering events between photons? Those likely occur at higher energies where the photons resemble to be particles? If it is possible, the cross-section may be extremely low.
There are a number of models to analyze propagation of light in scattering media, including ballistic, diffusion, Kublai-munk, Monte-Carlo etc. The multiple scattering resembles to be dominant in highly scattering media such as biological tissues, dense clouds, ash plume, dense aerosols and dusts even colloidal solutions and suspensions, while to my knowledge there is no perfect theory to describe multiple scattering in random media or turbid media. Can you suggest how to deal with this phenomena?
If E-M knots can exist, they emit no light, yet they possess energy, and hence mass. Their formation process is, I believe, still unknown, hence the possibility of large formation cross sections . What is the possibility that a large portion of the mass of the universe is tied up in knots?
Can someone explain the procedure by which we can view classic electromagnetism through quantum mechanics? Are we able to look at any field as an ensemble of particles (photons), and how can we develop classic field theory assuming quantum mechanics, such as beamforming .
When we measure the speed of light, we measure a beam or pulse. Are we correct to extrapolate this speed to single photons? Are we correct to infer that single photons have any definite speed, at all?
In QED, a definite speed is assumed.
In cosmology, the rest frame for the cosmic microwave background (CMB) appears to be a preferred frame of reference. For example, galaxies tend to have an average speed of zero relative to their local CMB rest frame. If an observer is traveling at a relativistic speed relative to the local CMB rest frame, the galaxy density would not appear homogeneous in all directions. Also there would be a substantial CMB anisotropy (unequal photon pressure) which opposes motion relative to the local CMB rest frame.
Now, ignoring the anisotropic effects of the CMB, is there any reason to believe that the laws of physics would not be the same in all frames of reference? For example, if a fundamental particle has relativistic kinetic energy exceeding Planck energy (about 2×109 J), then its de Broglie wavelength viewed from the CMB rest frame would be less than Planck length. Is this possible? Is it possible that experiments conducted in such an extreme frame of reference would find noticeable differences in the laws of physics? For example, would QED and QCD operations which depended on virtual particle creation and destruction be affected?
In his paper, Zoltan Imre Szabo argues that he can derive Lamb shift without renormalization. In short, he proposes to use De Broglie geometry to remove infinities in QEd.
So, what do you think?
According to QED, the photon is massless. What would the magnetic field prevailing today be that is associated with its mass? Will that magnitude be a proper seed to generate large-scale structure formations of galaxies?
While the classical, wavelike behavior of light interference and diffraction has been easily observed in undergraduate laboratories for many years, explicit observation of the quantum nature of light i.e., photons is much more difficult. For example, while well-known phenomena such as the photoelectric effect and Compton scattering strongly suggest the existence of photons, they are not definitive proof of their existence.
In particle physics, quantum field theories such as the Standard Model describe nature in terms of fields. Each field has a complementary description as the set of particles of a particular type. A force between two particles can be described either as the action of a force field generated by one particle on the other, or in terms of the exchange of virtual force carrier particles between them. The energy of a wave in a field (for example, electromagnetic waves in the electromagnetic field) is quantized, and the quantum excitation of the field can be interpreted as particles. In quantum electrodynamics (QED) a charged particle emits exchange force particles continuously. This process has no effect on the properties of a charged particle such as its mass and charge. How is it explainable? In theoretically a pure steady state spin current without charge current can induce an electric field. If a charged particle as a generator has an output known as a virtual photon, what will be its input?
What happens to a simple hydrogen atom, i.e. what happens to the energy binding between the electron and the proton, from the point of view of QED, when the hydrogen atom is close to a black hole?
After investigate the data from five experiments measuring the g-factor of electron and muon, I conclude that the experimental result has a value of approximately 1.000000003 times bigger than SM prediction. Detailed discussion is on section 4.2 of my paper.
For the Feynman path integral interpretation:
R. P. Feynman and A. R. Hibbs, Quantum Mechanics and Path Integrals, (McGraw-Hill, New York,1965)
You can find it here:
I have ONE only question. Given the quote of page 29:
"The phase of the contribution for a given path is the action S for that path in units of the quantum action hbar...The contribution of a path has a phase proportional to the action S:
phi[x(t)]=const exp((i/hbar) S[x(t)]) (2.15)"
*Question: What is the legitimation of such an assumption?
I think it is a great jump without reasoning, neither mathematical (why proportional and especially linear) nor physical.
We know that accelerating charges radiate. What if the charge was static in some reference frame and the observer was the one who accelerates with respect to that frame? Is there any relation to Unruh radiation?
New experiments confirm that the radius of the proton is smaller than expected from standard theory: http://www.newscientist.com/article/dn23105-shrinking-proton-puzzle-persists-in-new-measurement.html
I'm looking for a formal description of what exactly the "renormalization" problem is. I understand that some problems in physics can be renormalized, while some problems can't, and the renormalization problem has to do with this discrepancy. A thoroughly sufficient answer would include answers to the following questions: Formally describe what renormalization is. Answer why do we apply renormalization? How does renormalization affect the answers to the problem set? Which problem sets are we referring to? Why doesn't it work where the discrepancy exists?
I have fabricated Ag nanoantenna arrays on glass. It consists of cylindrical nanoantennas at constant separation in symmetrical environment. I have observed a splitting of single particle resonance dip in transmission spectra when the periodicity of the array is increased.
What could be the reason behind the splitting (or two dips) in transmission spectra? I am attaching the image of the transmission spectra for three different periodicities.
I have fabricated a periodic array of cylindrical nanoparticles and taken the transmittance spectrum. The single particle resonance dip that I am getting for the sample is getting blue shifted when the sample is coated with CdSe/ZnS quantum dots. Is it due to strong coupling of surface polaritons with the quantum dots? The absorption peak for the quantum dots are at around 613nm and florescence is at around 665nm. The dip in the transmittance spectra without quantum dot is around 650nm and with quantum dots is around 620nm.
I am working with a plasma simulation code, but physics of the code does not handle quantum Columb forces in small distance in the atom(between electron and proton) and treat them classically in every distance which does not seem true. I want to add an approximate formula of the force between electron and proton in atomic dimensions. I really don't want to solve Schroedinger equation so if you know where to find the code, guide me please.!?
This is not a derivative work, it is an entirely new approach to the problem and neatly explains why QED and GR can be so exact and yet somehow incomplete, and indeed exactly why the theories cannot be extended in their present formulation to a unified framework. I am trained as a process engineer, and finding a physics institute that takes my credentials seriously enough even to consider a critical review of my work is surprisingly difficult.
