Coupling Definition and 355 Threads

Hello everyone, I saw this video in youtube: And I have some questions, can someone please explain me the forces acting on this gyro? what is the momentum that keeps the cheese from falling, the direction of its action don't add up to me Also, how could i calculate the force needed to...

Homework Statement The lowest excited states of the Be atom correspond to a 2s2p configuration of optically active electrons. What 2s+1Lj components originate in this configuration? Assume that Hund's rules hold for the multiplet and deduce the ordering of the energy levels. Refer to a table...

AC coupling using NMOS Hello. What does AC coupling by using NMOS and PMOS actually means?

As far as I know: the possible orientations that the total angular momentum can take (given my Mj) are degenerate. if we apply a magnetic field, degeneracy will be lost and different states arise. this is the zeeman effect but when looking up on google for zeeman effect, a webpage used as an...

Sorry if this appears a basic question, but could you pls advise me is it possible to have a two identical vertexes but with different strength coupling? I have some toy Lagrangian and when I calculate Feynman rules I get for one vertex following expression: (M1+M2)*(combination of...

Hello, I've seen spin orbit coupling being explained by going to the rest frame of the electron and noting that the proton is then a moving charge and hence has a magnetic field, which interacts with the spin of the electron, effectively coupling the spin and angular momentum of the electron...

Hey all, Is there a way to rank the energy levels of a rare-earth ion in order of increasing energy just from the spectroscopic terms? Nd3+ has an electron configuration of [Xe]4f^3, which produces energy levels such as 4I, 4F, 2H, 4S, 2G, 4G, 2D, etc from the electrostatic interaction...

Hello all, I have recently encountered a problem in my understanding of how evanescent waves work. The problem will refer to the diagram found at http://www.popularscience.co.uk/features/nimtz2.jpg (while the evanescent wave isn't drawn this is the only example i could find). So...

Homework Statement A solid drive shaft is connected to an engine by a coupling, which has drive pins located on a pitch circle diameter of 80 mm (Note: the diameter of the pitch circle is greater than the diameter of the drive shaft). If the maximum power output of the engine is 90kW at 5000...

Hi, all. I'm wondering if anyone's done some simulation of magnetic material with LLG equation. The question is where can I find the value of exchange constant for a material. In LLG equation, the exchange constant is in the unit of "J/m", and the typical value is 10^-11 J/m, for some...

Would electromagnetic coupling between an electron with charge e and an electromagnetic field with scalar potential V_em add to its mass in the same way as its coupling to the scalar Higgs field? i.e. mass_electron = g V_Higgs + e V_em Somewhere I got the picture that a left-handed...

Hi everyone, even if I continue reading books about renormalization, I have the same basic doubts. So we have radiative corrections that give infinites etc.. So what we do is regularize and renormalize the theory. What is left at the end? Is it true that loops are no longer there since the...

Homework Statement Write all possible terms (n1 j1, n2 j2, …) J for these electronic configurations (considering jj coupling scheme): 1s2 1s2s 1s22s22p 1s22s22p5 The Attempt at a Solution 1s2 I have two electrons in the s sub-shell, since |l-s|<=j<=l+s then j1=1/2 and j2=1/2...

Hey everyone, I've been reading about the Spin-Orbit coupling effect in the Hydrogen atom. However, there's something I don't quite understand. The effect is being explained and calculated like this: we move to the rest frame of the electron, in which the electron has no orbital angular...

Hi, I'm studying a theorem that is valid for a small coupling constant λ in the Schrodinger operator below -\frac{d^2}{dx^2}+\lambda V The potential has a parameter α which defines its width. My question is: Starting with λ=1 and α=1, can I claim that if I increase the value of α (α >> 1)...

I am solving a Hamiltonian including a term \begin{equation}(x\cdot S)^2\end{equation} The Hamiltonian is like this form: \begin{equation} H=L\cdot S+(x\cdot S)^2 \end{equation} where L is angular momentum operator and S is spin operator. The eigenvalue for \begin{equation}L^2 ...

Hi, On a surface evanescent waves are created when total internal reflection occurs. However when this surface has periodic structures of appropriate periodicity (gratings, photonic crystals) the evanescent waves are "freed" from the surface and they propagate to the surrounding media. I am...

Hi, On a surface evanescent waves are created when total internal reflection occurs. However when this surface has periodic structures of appropriate periodicity (gratings, photonic crystals) the evanescent waves are "freed" from the surface and they propagate to the surrounding media. I am...

Hi physics forum, I have been reading David Griffith's book "intro to elementary particles" and he describes the decay of the pi-meson as "pure axial vector" Can someone tell me what this means, in terms of the weak force vertex consisting of this factor γu(1-γ5) Thanks, Mark

I want to know for a project for school if the value Electromechanical coupling coefficient of piezoelectric material will be the same in both directions? (from machanical to electric and from electric to mechanical) So in formula from: Em=Ee * K^2 and Ee=Em * K^2 and not something...

Hi guyz, I need some help in choosing the shaft couplings to connect the motor to the gear and from gear to the wheel. The motor shaft is 11 mm and the gear shaft is 24 mm. (Max torque 2 Nm, Max speed 70 rpm) Output of the gear shaft is 32 mm and the wheel shaft is 30 mm. (Max torque...

I'm considering a very simple method of powering a small electronic device from a typical current carrying outlet. I'm trying to make a theoretical prediction to the amount of current I could generate using magnetic induction. Problem: I have a straight current wire carrying an...

Please teach me this: In QTF theory book of Schoeder say: In nonlinear sigma model L=\intdx\frac{1}{2g^{2}}(\delta _{\mu}n^{\rightarrow})(consider2<d<4 where d is the dimension number of spacetime).If we consider the Lagrangian as the Boltzman weight of a partition function,then the...

Hi I have a simple question: We know from non-relativistic quantum mechanics that the spin of an electron couples only to the magnetic field, i.e. it processes around the magnetic field. How is this resolved in the relativistic context where it would seem that the spin should couple to...

I was reading a gauge field theory book and was told to refer to Quigg's Gauge Theories of the Strong, Weak, and Electromagnetic Interactions ch 9.2 The SU(5) Model, so I did not start from the first page of Quigg's book. In page 277, he started from Q = T3 + K To, where T3 is a generator...

I am on the last year of my study in nuclear ( engineering bachelor degree ). I will make a software that can coupling neutronic and thermal hidraulics in my thesis But i still confuse in case of choose the basic of software to make it because to handle Coupling neutronic and thermal...

Hi, I have got a single mode fibre (SMF) with core diameter 8.4 microns. Fibre is aligned in front of horizental reflective surface at a distance of 500 microns. Light from SMF make a spot size of 24 microns and is reflected and coupled back into SMF. However, if I tilt the reflective surface...

Suppose I have a mass M_0 (here denoted with lowercase zero because of previous discussions on relativistic mass), and I have a gravitational field \phi which can under make a shift of 180^o between a negative plane and a positive plane. Assume also that the mass is considered as a charge...

Hi everyone. This question is giving me a real headache (literally). It should be simple, but I’ve spend probably the last 4-5 hours trying to figure it out. The left side of my brain is redundant. Homework Statement The following specifications are used for the design of a flanged coupling...

I’ve been searching high and low for an answer to this question. What actually HAPPENS if two engines were to power one drive shaft? I heard back in the days that cars were built this way to break speed records, and I heard present day it is used in tractors, but what increase. My question...

Hello, I am searching for a text that talks about various non minimal coupling, why and how we introduced it. I know we can use it in inflation, modified gravity, or low energy quantum gravity, but I don't know how all these different topics lead to the same formalism, or almost for example with...

Hi, I am currently in training and while deriving the EOM for a specific lagrangian I am having difficulties to prove thatg^{\mu \nu} \delta R_{\mu \nu} B(\phi) = (\nabla_{\mu} \nabla_\nu - \square B g_\mu_\nu) I am ashamed it might be a simple calculus but I don't see how. If you had just...

Just a short question. As part of a dyno project, I am coupling two dc motors together with a timing belt. To allow the same rig to be used for different test motors, I am considering mounting this (test) motor on a table, which can be positioned in two directions on leadscrews. This would...

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?

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...

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...

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...

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...

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...

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

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...

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...

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...

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 ...

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...

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...

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?

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:

[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...

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?