Coupling Definition and 385 Threads

  1. P

    Coupling Capacitors: Value & Uses

    When you need to couple ac signals you use coupling capacitors. How do we decide its value and what are the uses of coupling capacitors?
  2. A

    Coupling to gauge fields - charge, doublets, etc.

    Hello, I'm trying to understand the standard model, and I'm confused in a few places. Correct me please, if I seem confused somewhere. I'll give my understanding first, and then a few questions. I'm certain I have a couple of things not straight in my head. Alright, so the standard model has...
  3. S

    How to Calculate Coupling Coefficient Without Mutual Inductance?

    Homework Statement I am trying to find the mtuual inductance between two p-core inductors (they share the same core) but I am not sure how the coupling coefficient would be calculated. I know the inductance of both coils. What else would I have to know in order to calculate the coupling...
  4. M

    How to calculate a Vibronic Coupling?

    I am very interested in calculating the vibronic couplings of a particular system quantitatively, but I am very new to Quantum Physics... so I will highly appreciate your guidance on where to start from? What kind of mathematics do I need to learn? I am quite puzzled because If I have...
  5. R

    Spin orbit coupling for atom at centre of complex

    Hello Forum, This is my first post. There is some preamble, but the problem itself is straightforward enough, even though I cannot solve it. I'm trying to calculate the spin orbit matrix for an alkali metal atom at the centre of a complex of 12 noble gas...
  6. E

    Running coupling of the weak interactions

    Can someone point me to a reference that explains how the (effective) running coupling behaves in the weak interactions(at 1-loop order). I couldn't find it... If I understand correctly, than the coupling is g = \frac{e}{sin(\theta_W)} where e is the QED coupling, which increases with energy...
  7. D

    Change coupling in a system with three angular momentum

    Hi! I'm doing some QM calculations and I'm coupling three spins j_1,j_2,j_3 If they are coupled in ls-coupling I can use the transformation |j_1j_2j_3(j_{23}):JM>=\\ \sum (-1)^{j_1+j_2+j_3+j}\sqrt{2j_{12}+1}\sqrt{2j_{23}+1} \begin{Bmatrix} j_1 & j_2 & j_{12} \\ j_{3} & J & j_{23}...
  8. Talisman

    The cause of entanglement / coupling

    The "cause" of entanglement / coupling Hi all, two questions. I don't have a physics background (but have a decent mathematical background, and have dabbled in QM). * What is the difference between entanglement and coupling? Wikipedia says they're "almost" the same thing, except for the...
  9. J

    What particles can the Z boson couple to in the standard model?

    Hi just wondering if anyone could tell me why the Z boson can couple to any standard model particle except forgluons and photons?
  10. B

    Coupling of angular momenta of many-electron atom

    There are two cases introduced in the lecture notes, depending on strength of spin-orbital coupling in individual electrons, since V_{SL} \propto Z^{4}. 1) jj coupling, which is valid for large-Z atoms, where spin-orbital coupling > electrostatic replusion between electrons 2) L-S coupling or...
  11. I

    How Do You Calculate the Landé g Factor for sd Configuration in jj Coupling?

    This is rather a straightforward question I believe, but somehow I'm not sure about the wording of it... Homework Statement Calculate g value (Landé g factor) for sd configuration in jj coupling. Homework Equations g = 1 + \frac{J(J+1) - L(L+1) + S(S+1)}{2J(J+1)} The Attempt...
  12. S

    Mutual inductance / coupling factor in twisted wire transformer

    I am trying to design UHF quadrature couplers from the following references: [1] 'Broad-Band Twisted-Wire Quadrature Hybrids' , http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1127996 [2] 'Twisted wire Quadrature Hybrid Directional Couplers' QST Vol 63 January 1978 pages 21-23...
  13. J

    How to Couple Two Modules in COMSOL?

    Hi, I want to couple two different modules of COMSOL. For example u is the solution of Module 1 and I want to give 0.95*u+a as subdomain settings parameter in module 2. Here a is a vector. I have succeeded with u and 0.95*u to use as subdomain settings parameter of module 2 but when I add a ...
  14. A

    Spectroscopy and Russell-Saunders coupling

    So, this has been bugging me for years (seriously). So my spectroscopy course says the following: 1) In an atom, for a closed subshell, for each electron possesing an m_l quantum number there is another electron possesing -m_l, which means that the sum M_L = \sum {m_l} = 0. I have no problem...
  15. N

    Determine the tension in the coupling

    A train consists of 50 cars, each of which has a mass of 6.6 e3 kg. The train has an acceleration of 1.5 e-1 m/s2. Ignore friction and determine the tension in the coupling at the following places. (a) between the 30th and 31st cars (b) between the 49th and 50th cars F=ma I got...
  16. H

    Abaqus2 - Kinematic Coupling VS Rigids

    What is the difference between Kinematic coupling in Abaqus and Rigids in Nastran? Why it is named as Kinematic Coupling... what is the physics behind the word kinematic and rigids?
  17. H

    (Magnetic Coupling) Why connect the capacitor in parallel to the inductor?

    I attach below the picture showing the principle of magnetic coupling in witricity (source: Electrons Unplugged by David Schneider, IEEE Spectrum, May 2010). I'm wondering why they connect the capacitor in parallel with the inductor. Why not in series? Any opinion? Thank you :smile:
  18. D

    Find tension in this train coupling

    [b]1. Homework Statement [/b A railway engine of mass 100 tonnes is attahched to a line of trucks of total mass 80 tonnes. assuming there is no resistance to motion find the tension in the coupling between the engine and the leading truck (a) when the train has an acceleration of 0.020 ms/1^2...
  19. D

    Rotational–vibrational coupling scale model

    I feel like playing with a scale model of this: http://en.wikipedia.org/wiki/Rotational%E2%80%93vibrational_coupling Do chemistry supply stores sell any? For educationnal purposes? Or do I have to build one?
  20. P

    Why do we need a coupling capacitor?

    Okay, I get that we need it to block DC while allowing the AC to pass. But if we have to block DC, why apply it in the first place? Is it because we apply it to a certain level and then we want to keep it to that level so we block any further interference by DC? Thanks.
  21. H

    Is the topological insulators a result of boundary conditions with SO coupling ?

    Hi, these days I have been trying to understand the essentials of the so-called topological insulators (TBI), such as Bi2Te3, which seem very hot in current research. As i understand, these materials should possesses at the same time gapped bulk bands but gapless surface bands, and spin-orbit...
  22. S

    Coupling AC and DC magnetic fields

    Hoping that one of you electrical wizards may be able to help me out! I have a 30A DC HP power supply and a 1000W stereo amp that I want to use create a 10mT static DC magnetic field superimposed on top of a 1 mT AC magnetic field. To generate the AC field I have a 1 uF snubber cap. in series...
  23. H

    Coupling coefficient and mutual inductance

    What is the relation between the coupling coefficient and the fraction of flux from one inductor going through the other inductor?
  24. S

    Spin Coupling, Matrix Building

    So I understand that the tensor product of two vector spaces constitutes a new vector space. In the case of spin coupling you have some arbitrary vector |x,z> where x represents the spin state of particle 1 and z represents the spin state of particle 2; bot spin states being general 2 element...
  25. A

    Difference between coupling and constrain equations in ansys

    What is the difference between coupling and constrain equations in ansys
  26. S

    Can you explain the coupling of surface plasmons with photons?

    Hi everyone, I am trying to figure out what is the coupling of a surface plasmon with a photon for the generation of a surface plasmon polariton. In fact I don't understand what a coupling is in this context. Some texts say that for the coupling to happen is necessary that the dispersion...
  27. humanino

    What Are the Experimental Constraints on the Running of the Weak Coupling?

    Dear all, would anybody know of references regarding experimental constraints on the running of the weak coupling ? This running is rather slow, and I guess we do not have evidence one way or the other, but since the SM and the MSSM have opposite slopes, I'd like to see what kind of...
  28. D

    Hund's rule and angular momentum coupling

    Hi. In Hund's second rule, it seems that we calculate the value of L simply by summing the L_z components of the individual electrons. But L has to do with the eigenvalue of the L^2 operator, i.e. the eigenvalue is L(L+1). So how can this be correct?
  29. I

    The weak force and effective coupling

    I just read something about the creation of deuteron in the first step of the pp cycle. Given that you have the reaction: p + p -> d + e^+ + v_e, where e^+ is a positron and v_e is an electron neutrino. Since there is a neutrino present, it is a weak interaction. In addition, as the interaction...
  30. M

    Exploring Non-Minimal Couplings in Particle Interactions

    What is the minimal coupling principle? Is it some sort of a prescription? Thx
  31. I

    Fermions with no mass, and helicity coupling.

    Hi, I was reading a lecture of qft and I found that two equations: \begin{flalign*} i \gamma^\mu \partial_\mu\psi_R - m\psi_L=0 \\ i \gamma^\mu \partial_\mu\psi_L - m\psi_R=0 \end{flalign*} after splitting in two Dirac's equation with Weyl's projectors. I found that really interesting that the...
  32. I

    Spin orbit interaction and LS coupling

    I hope someone can help me out here. I am having difficulty understanding what the difference is between the spin orbit interaction and LS coupling scheme in atoms. I know the spin orbit interaction (or spin orbit coupling) is due to the interaction of say an electron's spin with it's orbital...
  33. J

    General Relativity - gravity self coupling

    I realize that energy is a touchy subject in GR in dynamical situations, and people argued for a long time whether or not gravitational waves carried energy. But it sounds like there has been agreement for quite awhile now that they do carry energy. Since in weak gravity situations, we can...
  34. D

    Effect of Coupling Capacitors/Inductors

    More specifically, I have an NMOS oscillator, where the output is taken from the source terminal. I have to couple the output (50 Ohm load) with a coupling capacitor, but is this going to affect my calculations of the resonant frequency of the circuit? In my case, I have a Clapp oscillator...
  35. M

    LS coupling for identical electrons

    Let's say I'm considering the 3p^2 electrons. From the Pauli Exclusion Principle, we know that two electrons cannot have the same state, which in this case means ml and ms cannot both be the same for each electron. What this means is that the following 6 terms must not be allowed: m_{l1}...
  36. S

    Coupling Raoult's & Antoine's Equations for Mole Fraction & Temp

    Homework Statement Given the equation for Roaults law and Antoine equation for 2 species I need to recast these into a pair of coupled non linear equations to compute the mole fraction of species one and the temperature for given values of vapor fraction and the total pressure, Antoines...
  37. J

    The influence of crossing angle on amplitude in cable to cable coupling

    Homework Statement Hi all, I have this project i have to write but i am having trouble getting the necessary materials to aid my writing. The project topic is the influence of crossing angle on amplitude in cable to cable coupling. It is a magnetic coupling problem and i am supposed to design...
  38. A

    Calculate Spin-Orbit Coupling in 19K: Estimate <(1/r)dV/dr>

    Homework Statement The 4p → 4s transition in 19K produces a pair of lines at 766.49nm and 769.90nm. Estimate the value of <(1/r)dV/dr> for the optically active electron in 19 K Homework Equations The Attempt at a Solution help needed urgently please. All i know so far is...
  39. G

    Help needed: coupling light from a LED into an optical fiber

    First let me preface this by saying by physics-fu is remedial at best. I am a neuroscientist by training, but need a little help with piece of equipment I am designing, so any ideas or input would be greatly appreciated. Basically, I need to figure out a way to efficiently couple a light...
  40. H

    Solving Spin-Orbit Coupling in Hydrogen & Li+2

    Homework Statement One of the n=5 states of hydrogen is split by spin-orbit coupling into two levels with an energy difference of 0.0039 cm^-1 . Determine the 'l' quantum number for this state and predict the analogous splitting for doubly ionised Li . Homework Equations The fine...
  41. R

    In particle physics, what does 'coupling' mean?

    Hi, In particle physics, what does 'coupling' mean? I can't find a definition anywhere and books just assume you know what it is. For example, "the Higgs couples to light particles". Also, what does it mean to say that something strongly or weakly couples to something else? Any help...
  42. J

    Wideband AC Coupling for DDS Outputs

    Hello All, I've been playing worth some DDS output filter and amplifier circuits in the simulator and have run into an interesting little problem. I want to make an output that can range from 0.2Hz to 20Mhz and so far I have built a very nice reconstruction filter that can give me a very...
  43. E

    Identifying the Forces of the Weak Angle Coupling Constant: Spin or Charge?

    You still have not answered the question; What are the two forces of the weak angle coupling constant? We have spin and charge as known forces. If you can not specifically identify spin or charge as one of the two forces involved in the weak coupling constant than for all you know there...
  44. M

    Help calculating the Fermi coupling constant from the muon lifetime

    Homework Statement I have to find the Fermi Coupling Constant using my measurement of the muon lifetime. My measurement is 2.1786x10^-6s Homework Equations G_F=\sqrt{\frac{192.pi^{3}}{\tau.m_{\mu}}} The Attempt at a Solution I tried plugging in the numbers that I have and I get...
  45. V

    Is the coupling constant just Gz for all these interactions?

    Homework Statement Just a quick question, the Z can couple to leptons and there antiLeptons and quarks and there corresponding antiquark. Is the coupling constant just Gz for all these interactions? Or is it Gz.Sin(z) for some and not for others? Iv seen different notation and am wondering...
  46. N

    Continuity equation for Schrodinger equation with minimal coupling

    The Schrodinger equation with the minimal coupling to the Electromagnetic field, in the Coulomb gauge \nabla \cdot A , has a continuity equation \partial_t \rho = \nabla \cdot j where j \propto Re[p^* D p] (D is the covariant gradient D= \nabla + iA . My question is: is there any...
  47. J

    WiFi Antenna Coupling in Faraday Cage RV - Jack

    Hi - I live full time in an RV that is surrounded by aluminum - essentially a faraday cage, except for a few rather small windows. I'd like to mount a WiFi antenna on the roof and run a cable in a window or thru a small hole. Basic issue - how to get a good signal from a campground WiFi...
  48. A

    Does coupling to stress-energy imply coupling to Ricci?

    Suppose there is a field that couples to the stress-energy tensor. For simplicity, assume it's a scalar field coupling to T=T^\mu_\mu. Since contracting Einstein's equations with the metric yield the relation R = 8\pi G T, is it correct to say that the field also couples to R?
  49. P

    CMOS coupling to data processor for experiment

    In a spectroscopy experiment proposal I am working on, I had the idea to use a CMOS Image sensor (monochromatic) coupled to an interferometer to record data of the O2 green line in the atmosphere. In my ignorance, I cannot seem to figure out what kind of data processor I should attach to the...
  50. E

    Attitude Control of Flying Object using Gyroscopic Coupling

    I am not really solving an exercise for homework so hopefully this general forum is OK for my question. For my thesis, what is attitude control of a flying object with a reaction wheel, I am learning the basics from this NASA Technical Report: http://www.hot.ee/ronn/design_glob_anal_...
Back
Top