Interaction Definition and 653 Threads

  1. T

    I Schrödinger equation and interaction Hamiltonian

    Given 1A.1 and 1A.2, I have been trying to apply the Schrödinger equation to reproduce 1A.3 and 1A.4 but have been struggling a bit. I was under the assumption that by applying ##\hat{W} \rvert {\psi} \rangle= i\hbar \frac {d}{dt} \rvert{\psi} \rangle## and then taking ##\langle{k'} \lvert...
  2. A

    I Pluto's interaction with solar wind

    Do you think that new discoveries about how Pluto interacts with the solar wind suggests that Pluto should be reclassified as a planet?
  3. T

    A Interaction Hamiltonian coupling question

    System is composed of two qubits and the bath is one bath qubit. The interaction Hamiltonian is: $$\sigma_1^x\otimes B_1 + \sigma_2^x\otimes B_2$$ where $$B_i$$ is a 2 by 2 matrix. I try to interpret and understand this, is it the same as: $$(\sigma_1^x\otimes B_1)\otimes I_2 +...
  4. S

    Blackbody paradox applied to interaction of gravity with electrons

    Homework Statement How does the blackbody paradox argument show that the electromagnetic field cannot be classical while electrons and atoms are quantum mechanical? Should the same arguments apply to treating gravity classically and electrons quantum mechanically? Homework Equations The...
  5. N

    Calculating Force of Attraction Between Electromagnet and Permanent Magnet

    Lets us say that two magnets of unequal strength have one pole each lined up facing the other magnets pole. For convention magnet 1 is an electromagnet with an air core and a 200 gauss field strength. Magnet 2 is a neodymium permanet magnet rated at 20,000 gauss. Assume the "north pole of magnet...
  6. D

    I Energy levels in atoms & speed of interaction

    Hello, I wonder how the speed of interaction affects the energy levels in atoms. We know that electrons in atom are attracted to the protons in the nucleus through the electromagnetic force. Photon, the force carrier for the electromagnetic force, moves in empty space with the speed c (the...
  7. henrco

    Interaction of dust and starlight - extinction

    Hi, I haven't posted an Astronomy question before. I did see some Astronomy questions in this section so I posted it here. But if it's in the wrong place, for future reference, please let me know where it should be posted. 1) The first problem I need guidance on is the value I have obtained...
  8. P

    Find the electrostatic interaction energy between the dipole

    Homework Statement Consider the following pair of dipoles in one dimension. One of the dipoles: -ve dipole positioned at (-D/2, 0) and +ve (+D/2, 0), with the origin between them. Other dipole: -ve dipole positioned at (r-d/2, 0) and +ve at (r+d/2, 0), with (r, 0) being the centre. Show that...
  9. S

    A Is Chiral Symmetry Present in Weak Interaction?

    Dear all Do we have chiral symmetry for weak interaction? I know that weak interaction is chiral. thank you
  10. N

    A D Branes and Gluon-Quark Interaction.

    I have been watching Prof Susskind's lectures on String Theory. I am trying to understand a little more about D branes. I am trying to reproduce a basic quark-gluon interaction. I have the following:http://www.firstcoasttutors.com/images/pf.jpg I think this might describe the right hand...
  11. LotusTK

    How do the magnetic fields of a magnet and a wire interact?

    Im not too sure about the (ii) part of this question. The mark scheme is very poor too and gives very little information (which is always the bloody case with A level mark schemes). I don't know what i can say about how the two fields interact. Can someone tell me what i am missing in my...
  12. A

    Find the interaction potential energy

    Homework Statement 2 concentric shells are placed with inner shell having charge q and outer charge -q, with radii a and b respectively. Homework Equations don't know The Attempt at a Solution the question asked me to find self energy of the 2 shells and interaction potential energy,i found...
  13. J

    How does a virtual particle becomes a point interaction?

    If you want to show that a propagator of a heavy particle reduces to a point interaction at distances large compared to the inverse mass of the particle by Taylor expanding the propagator (for simplicity take 1-dimension): $$G(x)=\int^\infty_{-\infty} \frac{dk}{2\pi} \frac{e^{-ikx}}{k^2+M^2}=...
  14. G

    How can EM interaction escape a black hole?

    Hi. Charge is one of the few properties a black hole can have. EM interaction is mediated by photons. How can they escape the BH?
  15. J

    Interaction of light with a shockwave

    Hello, I am trying to understand how light would interact with a shockwave, but for that I need to make sure my understanding of the physics of light is correct. It is my understanding that light travels independent of a medium because of the electromagnetic waves it produces. A wave, such...
  16. edguy99

    Long-distance correlation, information, and faster-than-light interaction

    [Mentor's note: Split off from https://www.physicsforums.com/threads/an-abstract-long-distance-correlation-experiment.852684/page-6 because this subthread was discussing possible mechanisms behind the phenomenon] My take on these: 1) - not weird at all - you send a photon in one direction...
  17. G

    Light interaction with charged particles

    Does anybody know what happens when say a laser accelerates charged particles? Do photons get absorbed and the intensity of the laser drops, or do they get absorbed and scattered and there's a redshift of the photon etc
  18. gracy

    How to find electrostatic interaction energy?

    How to find electrostatic interaction energy between two uniformly charged conducting spheres /uniformly charged non conducting spheres or between a charge and uniformly charged spherical shell I mean what is general method of finding electrostatic energy in a given system.I don't have any...
  19. S

    Slater determinants in Configuration Interaction

    How does one create the single or doubly excited slater determinants in CI? What I mean is using HF, when I get the MO's, I can create the HF slater determinant which runs over electrons in rows and orbitals in columns. What is the form of single or doubly excited slater determinants? Sorry if...
  20. G

    Understanding the Effects of Laser Interaction with Ions in Doped Fibers

    Will a laser exposed to ions (doped fibre) spread out in the direction of polarisation as momentum sends the peaks in one direction and the troughs in another. Or, as total momentum is 0 does the wave continue on straight.
  21. GuhaGubindam

    Photon-Atom Interaction: Effects on Electron and Nucleus Energies

    Ok, i want to make the question clear: 1) Let's say I strike my hydrogen atom with a single photon; will the electron rise up a shell level, and the nucleus become more energetic as well? OR just the electron will rise up a shell level, and the nucleus will be undisturbed? 2) Also, if I strike...
  22. FrancescoS

    Computing propagators with derivative interaction

    Hi guys, I'm working with this interaction Lagrangian density ##\mathcal{L}_{int} = \mathcal{L}_{int}^{(1)} + \mathcal{L}_{int}^{(2)} + {\mathcal{L}_{int}^{(2)}}^\dagger = ia\bar{\Psi}\gamma^\mu\Psi Z_\mu +ib(\phi^\dagger\partial_\mu \phi - \partial_\mu\phi^\dagger \phi)Z^\mu,## with ##...
  23. S

    Unphysical nature of ##\phi^{3}## interaction

    In page 77 of Peskin and Schroeder, it's mentioned that for a ##\phi^{3}## interaction, the energy is not positive-definite unless we add a higher even power of ##\phi##. Can someone please prove this statement?
  24. N

    Interaction of Two Spin 1/2 Particles

    Hi buddies. I recently finished my quantum mechanics course, however, I would like to know the solution of this exercise because i couldn´t solve it on my last exam, and i would like to take this doubt off. An operator ##F## describing the interaction of two spin ##\frac{1}{2}## particles has...
  25. carllacan

    What determines light-matter interaction processes?

    Hi. Sorry for the awkwardly phrased title, I couldn't think of anything better that summarizes my question. I've been learning about different types light-matter interaction, specially photon- electron processes, and there's something I don't get: what determines whether this process will be...
  26. H

    Order of scalar interaction impact Feynman diagrams

    On page 60 of srednicki (72 for online version) for the $$\phi^{3}$$ interaction for scalar fields he defines $$Z_{1}(J) \propto exp\left[\frac{i}{6}Z_{g}g\int d^{4}x(\frac{1}{i}\frac{\delta}{\delta J})^{3}\right]Z_0(J)$$ Where does this come from? I.e for the quartic interaction does this...
  27. J

    Dual Lorentz force for classical spin-orbit interaction?

    Electric and magnetic parts of Maxwell's equations are kind of similar, so physical effects relating these properties have many 'dual' analogues - with exchanged places. For example in Aharonov-Bohm effect, the phase of charged particle depends on side of magnetic flux tube it comes through...
  28. K

    What is the Quantization Scheme in Frohlich's Electron-Phonon Interaction Paper?

    I am reading Frohlic's paper on electron-phonon interaction. Frohlic.http://rspa.royalsocietypublishing.org/content/royprsa/215/1122/291.full.pdf Here author has introduced the quantization for complex B field in this paper and claimed to have arrived at the diagonalized form of the...
  29. HanningWu

    How could this,Sigma0 decay into Lambda and gamma, happens?

    I found an article, titled Electromagnetic Decay of the Σ0(1385) to Λγ , in the arXiv telling that the reaction Σ0→Λ+γ can happen through electromagnetic interaction. However, if I examine the conservation of parity. Parity on the left side is even(P(Σ0)=+), but that on the right side is...
  30. F

    Interaction picture - time evolution operator

    Hey all, I got some question referring to the interaction picture. For example: I have the Hamiltonian ##H=sum_k w_k b_k^\dagger b_k + V(t)=H1+V(t)## When I would now have a time evolution operator: ##T exp(-i * int(H+V))##. (where T is the time ordering operator) How can I transform it...
  31. K

    Yukawa interaction and chirality.

    i still can't figure out how the higgs vev couples opposite chiral fermions(spinor components) to compose a physical electron/positron. (and actually in kurros 's thread it says that the yukawa interaction does not flip chirality nor helicity. what the hell does it mean for the yukawa...
  32. S

    Feynman rules for Lagrangian with derivative Interaction

    Homework Statement The lagrangian is given by: L = \frac{1}{2} \partial_{\mu} \phi \partial^{\mu} \phi + \frac{\alpha}{2} \phi \partial_{\mu} \phi \partial^{\mu} \phi And the question is to find the feynman rules. Homework EquationsThe Attempt at a Solution I started by using the...
  33. B

    Interaction of Gaussian Beams with Optics

    Homework Statement In a youtube video() it is explained how gaussian beams propagate through an optical lens. Using the complex parameter q \frac{1}{q} = \frac{1}{R} - \frac{j\lambda}{\pi n w^2} (with R the radius of curvature), one can use the ABCD matrix to calculate the effect of an optical...
  34. A

    Yukawa Interaction: What Is It & Why Not Part of Standard Model?

    Hello There I may have some mistakes so correct me when I wrote something wrong.My question is:what's the yukawa's interaction and why it is not part of standard model?
  35. M

    Transition dipole moment: cause or result of interaction?

    According to the wikipedia article about the transition dipole moment: When an atom or molecule interacts with an electromagnetic wave of frequency , it can undergo a transition from an initial to a final state of energy difference through the coupling of the electromagnetic field to the...
  36. N

    Running Coupling for Weak Interaction

    How can I derive the running coupling for the weak interaction. I have found derivations for QED and QCD that involve the β function http://www.physics.umd.edu/courses/Phys741/xji/chapter1.pdf but I can't find anything specific for the WI. Thanks.
  37. S

    Software package for modelling electromagnetic interaction

    Hello! I would like to ask about any software package, where interaction between a moving particle and a monolayer can be simulated. What i need to get is a spectral angular density distribution in the far-field zone within optical frequency range for a problem when a particle crosses a...
  38. C

    Do protons have stong nuclear interaction with other protons

    I was wondering if protons exchange strong nuclear interaction/force with other protons or do protons exchange strong nuclear interaction/force with just neutrons OR do all protons and neutrons exchange strong nuclear interaction/force with all protons and neutrons. Protons exchanging strong...
  39. Garlic

    Decay through gravitional interaction

    Hello, I know that the gravitational force is the weakest of all forces (it is 10^-38 times weaker than the strong force), so it isn't possible a particle to decay through gravitational interaction. As far as I know, the strength of fundamental forces can change during different ages of the...
  40. TotalNovice

    B Speed of interaction between entangled particles

    When the spin of an entanglement particle is established, it is said that the corresponding spin of its entangled twin is revealed immediately, (via wave collapse?), and that this interaction can occur across a substantial distance. It has also been said that this immediate interaction can occur...
  41. S

    Interaction Between Light and Black Holes

    Since light is entirely incapable of slowing down, what happens when light approaches a black hole such that it's trajectory passes through the exact center of the black hole? It seems, based on what I currently know, this would mean that the gravitational force pulling on the light would be in...
  42. D

    Interactions between field operators & locality in QFT

    Why is it required that interactions between fields must occur at single spacetime points in order for them to be local? For example, why must an interaction Lagrangian be of the form \mathcal{L}_{int}\sim (\phi(x))^{2} why can't one have a case where \mathcal{L}_{int}\sim\phi(x)\phi(y) where...
  43. Ryan Reed

    Do Spin-Orbit Interactions change the Orbital of an Electron

    Does the orbital of an electron change when it experiences a spin-orbit interaction, and if so, how?
  44. Mr Wolf

    The charge interaction as a force

    I think this thing came to my mind some times after I studied Electromagnetism when I studied Physics; otherwise, I would have asked it to my professor. (Incidentally, I'm still studying and I'm involved in Electromagnetism, but for a totally different course :wideeyed:) We know from Coulomb's...
  45. Gift Sama

    Find Force of Multiple Charges on Origin Charge Q

    what are the generalised and more quicker ways of finding Force that multiple charges (4 charges along the y-axis and x-axis at most) exert on the origin charge Q. i have used a cartesian plane to try solve for the vectors but seem to not get to the right answer.
  46. naima

    What is the equivalence to the free field in the interaction picture?

    I read in this http://arxiv.org/abs/1501.05658']paper[/PLAIN] "Unfortunately, the derivation of the Dyson series perturbation expansion relies on the use of the interaction picture, in which the interacting field is unitarily equivalent to the free field" It may be obvious but could you tell...
  47. F

    What is interaction Lagrangian of matter and graviton fields

    What is the interaction Lagrangian of matter and graviton fields?So(on the answer)we can say about the nonrenormalization.Why is the divergence of two gravitons diagram able to be the limit of the coincidence of the verties.So we can say about the nonrenormalization.
  48. N

    How to compute the vertices from interaction lagrangian?

    Hello all, If I am having the the effective lagrangian which is actually free + interaction lagrangian (obtained from the minimal substitution for pseudoscalar and vector mesons). then how to compute the vertices of the interaction ? I have taken into consideration of all symmetry breaking...
  49. olgerm

    Potential energy in strong- and weak- nuclear interaction

    Schrödinger equation for N-particles is: U_{System Potential Energy}(r_1,r_2,r_3,...,r_n,t)-\sum_{n=1}^{n_{max}}(\sum_{d=0}^{d_{max}}(\frac{d^2Ψ(r_1,r_2,r_3,...,r_n,t)}{dx_n^2})*\frac{ħ^2}{m_n})=i*ħ \frac{dΨ(r_1,r_2,r_3,...,r_n,t)}{dt} Where \sum_{d=0}^{d_{max}} is summation over dimensions...
  50. caters

    What Happens When Two Bubbles Interact?

    I have seen 4 things happen when 2 bubbles come towards each other. 1) I have seen 1 or both bubbles pop 2) I have seen the bubbles bounce off each other 3) I have seen the bubbles come together and stay there 4) I have seen complete fusion of the bubbles into 1 bigger bubble that then...
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