Coupling Definition and 355 Threads

My question relates to the very origin of the elementary particles. I understand that the Higgs field breaks the mass symmetry of the elementary particles and that the Higgs field-based mass value for each particle is dependent upon the strength of interaction between each elementary particle...

I was thinking about units and started wondering about coupling constants. In unit-independent form, the fine-structure constant is defined as \alpha = \frac{k_e e^2}{\hbar c} I don't have a deep knowledge of particle physics but I know that there are weak and strong charges which enter the...

In this problem, the left wheel is connected via a slot and consequently I don't see how the wheel would undergo any motion at all until such time that the rod moves all the way to the edge of the slot because before this time, the joint can just undergo rotational motion to compensate for the...

Is anyone familiar with a $$ SU\left( 3 \right) \otimes U \left( 1 \right){}_d$$ or $$SU \left( 3 \right) \otimes SU\left( 2 \right) \otimes U \left( 1 \right)_d $$ model? Kind of what I'm currently interesting in working with, but I don't have access to anything other than the arxiv.cheers.

First a little intro. The process of renormalization introduces in a QF theory a renormalization scale μ. Physical quantities do not depend on it, as a change of μ comes along with the change of the coupling g(μ) according to the RG law. But why then the physics can change so drastically...

Can someone please look at this and tell me what's going on here? I'm trying to understand the coupling coefficient k between two wire coils some d distance apart. I found this but I am lost! Please help!

Homework Statement In the circuit of Figure 4-2, let N1=2000 turns, N2=1000 turns, R=0, Z1=0 and ZL=300+j400 (Ω). If V1(max)=1500 V, what is the average power delivered to ZL? A. 5400 W B. 2700 W C. 337.5 W D. 675 WHomework Equations V2=(N2/N1)V1The Attempt at a Solution since turn factor is...

Homework Statement Homework Equations k=1 inductor(left)=400j inductor(right)=1600j The Attempt at a Solution how to do this! help me. my caluclator can't solve 3 rectangular form mesh currents equations so i cannot solve for individual currents for all 3 loops! i just guessed...

Could someone point to me where they derive the follow effective Lagrangian for the Graviton coupling to matter L = \frac{1}{M_{pl{}}}h^{\mu \nu}T_{\mu \nu}

In these notes(at page 71) Bilal put some emphasis on that the running coupling on a certain scale ##\mu## is defined in such a way that the logarithms in the expansions of the vertex function small. Or equivalently it is defined such that running coupling on the scale in question is always a...

(PS: this post was also posted at the quantum mechanics/field theory forum, but I did not get any replies there) Often when one speaks about the effective QED coupling one defines it as $$e = \frac{Z_2 Z_3^{1/2}}{Z_1} e_0 \ \ \ \ (*)$$ when ##Z_1 = Z_2## by the Ward identity this...

Often when one speaks about the effective QED coupling one defines it as $$e = \frac{Z_2 Z_3^{1/2}}{Z_1} e_0 \ \ \ \ (*)$$ when ##Z_1 = Z_2## by the Ward identity this turns out to be ##Z_3^{1/2}e_0## and some authors just define the coupling to be this right away. So why do some make a...

In conventional renormalization one is first supposed to compute a scattering amplitude of interest in terms of bare quantities ##\lambda_0, m_0...##, then compute these bare quantities in terms of physical quantities, i.e. ##m(m_0,\lambda_0,...), \lambda(m_0, \lambda_0,...)## and substitute...

In most introductory discussions on spin-orbit coupling in the hydrogen atom that I've come across, the analysis is often performed on a Bohr-orbital model. The electron is treated as orbiting the nucleus in a circular orbit. They then transform to the frame of the electron, and then assert that...

I have a two way radio that I'm trying to control remotely through 120 ft of 25 conductor cable at 22 gauge. The radio uses serial communication between the actual transmitter and control head unit. After I wired the pin's up accordingly, there is to much noise pickup through the cable and it...

I understand that by uncertainty relations, it is possible use an EFT to a range of energy, forgotten the interactions for bigger energies. But, ¿ why change the values of coupling costants? And, ¿ how can tell that there is no intermediate particle that happens with low probability in...

How is the effective (or renormalized) coupling constant at a given momentum scale scale measured? If one wants a definition which makes it easy to measure I would think it would be natural to use the LSZ formula which connects the measurable Feynman amplitude with the amputated greens...

Hi everyone, I'm reading about the Wigner-Eckhart Theorem and the coupling of spherical tensor operators in Sakurai's Advanced Quantum Mechanics. I then came across this http://cc.oulu.fi/~tf/tiedostot/pub/kvmIII/english/2004/09_tensop.pdf, which states these concepts in Theorem 1 and 3...

The W couples to left-handed particles only. What about the Z? Is it the same? Thanks in advance!

I was reading Griffiths's book on quantum mechanics. In chapter 6, he tried to derive the spin-orbit coupling using a classical approach. H=-\vec{\mu}\cdot \vec{B} 1. Finding the relation between \vec{μ} and \vec{S} He consider a spinning charged ring with mass m, radius r, total charge...

When testing Bohr's theory by Franck-Hertz experiment, we have electrons colliding with Hg atoms. a Hg atom will absorb electron's energy when this energy can make it jumping to a higher energy level. I wonder Hg is more like L-S coupling or j-j coupling, for I want to measure its higher...

Thanks. I started a new thread, because I've seen what seemed to me a contradictory claim in Carroll's GR notes (Eq 5.38) - he says diff invariance is enough to get covariant energy conservation. I've never understood whether Carroll's claims and the ones in these papers are really...

I have been given a formula Kne = \frac{1}{4Td}(CZo+\frac{L}{Zo}) I've been given C as 10pF and L as 80nH and Zo as 70.7. I have calculated Td from the formula propogation velocity = 1/\sqrt{LC} and the line capacitance and inductance are 400nH and 80pF and then divided this into 0.05m the line...

Hi, If we have a system on N atoms confined to dimensions much smaller than the wavelength corresponding to the transition, we see superradiant decay. Now, in these cases, we always assume that the excitation is symmetrically or antisymmetrically distributed. For instance, if we have one...

hi all, these days i m going through Arther Beiser's modern physics book where i read about the total angular momentum in many electron atoms..now i could understand the LS coupling and spin orbit effect how they combine to form total angular momentum but if i m given the magnitude of L=2...

is coupling G (graviational coupling) actually a constant of nature or it can vary?

I don't know if you are familiar with it, but in pertubationt theory for hydrogen it is handy to look for eigenstates of J = L + S since this commutes with the hamiltonian (L and S are not separately conserved). My book then says that the good quantum numbers are: n,l, j, mj I must admit I'm...

I have a question about how my book derives a formula. It starts with: We have an electron free too move on a cylinder and from the cylinder there is an electric field pointing radially outwards. Now for an electron moving in an electric field it sees local magnetic field given by: B =...

Recently saw the invention on PhysOrg for a device the recharges a AA battery using "waste" EM radiation from the ambient environment. In the photos, the author was placing an array of them near a power sub-station. This brings up two questions: 1) Does this create an inductive load on the...

In standard QM textbooks, when calculating the spin-orbit interaction term as a relativistic perturbation for hydrogenic atoms, it is said that the term gives 0 contribution for the s-orbitals (l = 0). This is apparently because the term has the form of S*L and L=0 for the s-orbitals. However...

Homework Statement Let U, V be random variables on [0,+\infty) with probability density functions f_U(x)=2e^{-2x} and f_V(x)=e^{-x}. 1. Give a coupling of U and V under which \{U\geq V\} with probability 1. 2. Give a maximal coupling of U and V. Homework Equations Cumulative distribution...

In the attached picture R1 and R2 are assumed to be equal so that they form a voltage divider. Without any signal into C1, the voltage of the base of the NPN BJT is (1/2)Vcc. If a square wave with Vhigh = (1/2)Vcc and Vlow = 0V, and a duty cycle of 80% is fed into C1, what would be the...

the proton is stationary, and we're assuming there is no magnetic field in the rest frame of the proton. I know if we move to the rest frame of the electron there will be a magnetic field. but shouldn't we be able to analyze it in the rest frame of the proton?

Can someone explain to me how to get the states for an electron in a given orbital (lets say... d orbital l=2) and how to calculate the Clebsch-Gordan Coefficients for this system? I tried reading my book but I'd like someone to explain in simpler language.

i'm reading through halzen and martin's chapter 12 on the weak interaction which they calculate the fermi coupling constant form oxygen beta decay using \Gamma = 1/\tau = G^2E_0^5/30\pi^3 with E_0 = 1.81MeV and \tau log 2 = 71 sec. they get G\approx 10^{-5}/m^2_N. where m_N is the nucleon mass...

Hi I am studying how the spin orbit interaction in certain materials can lead to topological insulator effects and realize it has something to do with the effects of the SOC on the band structure of the material (Bi2Se3), possibly due to the inversion of the valence and conduction band but I...

Hi, Does anyone have an intuitive idea of why it is always the valence bands split under spin/orbit coupling, but not conduction band? (or a much smaller splitting than valence band) I know through tight-binding calculations, if I plug in numbers correctly, conduction bands always have...

Homework Statement The coupoing coefficient of K' of a linear transformer is adjusted so that Zab is purely reissitive when ω= 25k rad/s. What is Zab? Homework Equations Not sure The Attempt at a Solution I'm not sure how to being this problem. For one, from what I've been...

Hi I was learning about wireless power transfer. It is stated that inductive coupling can be use to transfer large amount of power. But efficiency is poor if distance is large. The reccomended solution for this problem is energy transfer through magnetic coupling. May I know what is the...

hi guys , can someone help me with references about this case ? thx

Rotating Coupling Pin--Mechanical Failure as a Safety Precaution Hi everyone, I am RagingCalm, a mechanical design engineer. I hate to ask for help on my very first post but considering that I am utterly stumped and no one at the office can help me...well...ummm...help, please. :frown...

I know there are many deep issues that come up in attempts to do quantum gravity, but I suspect that the following is not deep but easily explained by someone who knows more about this than I do. Suppose two neutrons are interacting gravitationally. The Feynman diagram that I would naively draw...

I have recently started my phd on ab-initio simulations, and have several confusions about the calculations (lets say with a method like DFT) of solid crystal structures. 1. what exactly are the exchange and correlation phenomena. I have read texts and books which describe its physical...

Hello! So I've been working on a project to couple a 15 bar diode stack into a 600 micron fiber. Using an old design that I've used in the past but it's giving me some issues. I don't have a plethora of experience with ZEMAX so I'm hoping to leverage the collective consciousness of the...

My course on QFT follows Srednicki's book. He derives the running of coupling constants in different theories in the following way: When he uses dimesional regularization (going to x-\epsilon dimensions), he has to introduce a parameter \mu with dimensions of mass in oder to keep the coupling...

Hi everyone, I am trying to understand some things about confinement in lattice QCD. It has been very difficult so far to find a clear book chapter or review article, so I had to resort to the original literature in many cases, and I came across some apparently incompatible statements about...

So this is the op amp I am looking at and I have a few questions, not entirely sure how to ask them, but I'll ask more as I find out more http://postimage.org/image/i228xrkj7/ http://postimage.org/image/i228xrkj7/ So the capacitor C1 and C3 are used to block DC, but when you add these do you...

A shaft of a total length L, connected via coupling C to the engine on the left-hand side, transfers the power P while rotating with n revolutions per second. A gear with pitch diameter D1 and thickness t1attached to the shaft at the distance Lg from the coupling C is in mesh with the driven...

In the limit of weak coupling, G\overline{ρ}<<1, the BCS pairing gap equation gives that Δ \propto exp(-1/G\overline{ρ}). \overline{ρ} is the level density.This cannot be developed as a power series in the interaction strength G. Does this imply that there is a phase transition between a...

I have read that between breadboard nodes there can be as much as 25 pF of capacitance. I have a much better time understanding how parasitic induced voltages work, with respect to magnetic fields. I have a much harder time understanding how signals can become noisy due to parasitic...