Coupling Definition and 385 Threads

Homework Statement Considering the atom made of an electron and a positron. The spin-orbit Hamiltonian is: $$H=\frac{e^2}{4\nu^2c^2r^34\pi\epsilon_0}\vec{L}\cdot\vec{S}$$ with ##\vec{L}## the relative angular momentum, with ##\vec{S}## the total spin and ##\mu## the reduced mass. Finding the...

Hello. I have a question about the place where signal enters or gets out from a line (strip or not) Sorry I don't know the exact word in english, may be tap or tapping ... For different lines 1/4 or 1/8 wavelength these points are sometimes @ a 1/4 from the cold point, sometimes elsewhere. I...

Homework Statement Vertex Feynamnn rule for computing the time correlator of fields under an action such as, for example, Say ##S_{int} [\phi] =\int d^4 x \lambda \frac{\phi^4(x)}{4!} + g \frac{\phi^4(x)}{4!} ##, ##\lambda## and ##g## the coupling constants. Homework Equations see below...

hi to everybody, can somebody tell me, ferrit rod coils, is a transformer? if yes how do you calculate? what is the formula how you select the coupling inductor L2 or L3... because like i read the maing inductor must connect to capacitor(for frequency to find min and max i understand) but...

sorry I am going slightly off the topic. <<Moderator's note: split off from this thread.>> I asked this question because I'm studying a paper concerning the presence of spin orbit coupling at the interface between two metals. This is the part of the paper I'm studying: "Our aim is to...

I have read in the internet that "One naturally derive the dirac equation when starting from the relativistic expression of kinetic energy: ##\mathbf H^2=c^2\mathbf P^2 +m^2c^4## where ##\mathbf P## is the canonical momentum. Inclusion of electric and magnetic potentials ##\phi## and ##A## by...

Mossbauer spectroscopy is an example of a nuclear (de)excitation coupling to a lattice phonons Are there any other examples of this phenomena ?

Can I use a Clutch Plate assembly along with drive shaft to connect Engine & dynamometer? I am facing an issue where in CRDi engine, at a position of accelerator pedal RPM is increasing from 1300 to 2000 without any change in accelerator pedal position. And a lot of vibrations takes place at...

Is it possible to couple a thermal hydraulics code with a kinetics one ? , main purpose is to study the behaviour of kinetics due to a LOCA or any other changes regarding the coolant/moderator flow " talking about a PWR " .

Most QFT texts, such as Peskin&Schroeder and D. Tong's lecture notes, contain a mention that the renormalizability of an interacting theory requires the coupling constants to have correct dimensions, making scalar fields with ##\phi^5 , \phi^6, \dots## interactions uninteresting. Maybe there are...

Hello all, I am confused about Huang-Rhys parameter and electron-phonon coupling. I read a chapter of a book The biophysics of photosynthesis, called "Electron–Phonon and Exciton–Phonon Coupling in Light Harvesting, Insights from Line-Narrowing Spectroscopies". I am confused about the...

Homework Statement Homework Equations KVL and KCL The Attempt at a Solution I am very confused by the dot convention and how it works when writing your loop equations... I can't find any good videos or explanations online and I am completely lost with this dot convention. So I understand...

I'm building a small wind turbine and I'm trying to find a way to make the metal rod where the propellers are rotate the axle of a small motor. The diameter of the rod is 1/4" and the diameter of the axle of the motor is about 2 to 3 millimeters. This is more or less the design of the turbine...

Hello all. I was wondering if there was any generalized (simplified) formulation of spin-orbit coupling equation like the ones we see for energy transfer between two species (molecules or ions). Foerster and Dexter's equation are famous simplified formulation of energy transfer. Multipole...

Hello PF community! Quick introduction: I'm a fresh-out-university mechanical engineer working on a telescope altitude-azimuth mount hobby project. The mount will be designed using rotary platforms (powered by internal motors) to move the mount structure in the altitude and azimuth directions...

I use a 2" coupling to mount my DSLR on the scope. However, I have an 90 degree mirror angle in the 1.25" size, and would like to use it sometimes for convenience getting my eye on the viewfinder/lcd screen. I was wondering what drawbacks, if any, there were in stepping down the diameter of...

Greetings everyone! I have been a long-time lurker on here and have just recently signed up. I'm unsure if this was the correct forum to post this in, so I apologize in advance. My question isn't exactly homework per se - I am currently studying for my MCAT and have been trying to wrap my head...

Hi, I can't find my inductance calculations book. Say that you were considering magnetic flux linkage more from a geometric perspective: -Does the mutual coupling coefficient for a series of coils all on the same steel core add up to a maximum total of ~1? Because I tried simulating a three...

Hi, I have a couple of questions regarding re-wiring a three phase transformer. Say you have a three phase TX with a ratio of 415:22 and you want to use it as a single phase step-up TX (excite it with a variac or something), this is a thought-experiment. If you excited only the middle leg of...

Hi! According to the book "Renewable Energy on Power Systems" by Freris & Infield, the voltage rise due to injection of power in pcc can be estimated from the Thevenin equivalent representing the network "upstream" pcc (Figure 1). The Thevenin voltage can be taken as the nominal voltage in the...

In analogy to the fine structure constant, the dimensionless coupling constant of gravity is defined as some reference mass divided by the Planck mass, squared. But what is the reference mass?? I have read thread...

Is it possible to couple a 200μm core fiber into a 50μm core fiber by using a 4x magnifier/reducer?

I just made a capacitive coupling clamp with aluminium. When I fed a burst signal of 500V, I could only see 6V across the plates. I have used 1.5mm thickness aluminium sheet. Why its not working as expected?

Hello all, I'm trying to measure the effect of adding charges in the silicon dioxide separating two interconnects in VLSI circuits and how it will effect the coupling capacitance between these two wires. How can I measure this effect ? The VLSI circuit I'm working on has frequency of 500...

Consider the Einstein-Maxwell action (setting units ##G_{N}=1##), $$S = \frac{1}{16\pi}\int d^{4}x\sqrt{-g}\ (R-F^{\mu\nu}F_{\mu\nu})$$ where $$F_{\mu\nu} = \nabla_{\mu}A_{\nu}-\nabla_{\nu}A_{\mu} = \partial_{\mu}A_{\nu}-\partial_{\nu}A_{\mu}.$$ This describes gravity coupled to...

The Yang-MIlls Lagrangian is given by ##\mathcal{L}_{\text{gauge}} = F_{\mu\nu}^{a}F^{\mu\nu a} + j_{\mu}^{a}A^{\mu a}.## We can rescale ##A_{\mu}^{a} \to \frac{1}{g}A_{\mu}^{a}## and then we have ##\frac{1}{g^{2}}F_{\mu\nu}^{a}F^{\mu\nu a}.## How does the second term change? Does the...

Hello, I have a general question regarding energy coupling in multi phase flow. My question comes is based on the text from this book...

The beta function for the strong coupling ##g_3## is given by ##\displaystyle{\mu \frac{\partial g_{3}}{\partial\mu}(\mu) = - \frac{23}{3} \frac{g_{3}^{3}(\mu)}{16\pi^{2}},}## with ##\alpha_{3}(\mu = M_{Z}) = 0.118.## We can use separation of variables to solve the beta function equation...

I was looking at grotrian diagrams for helium and I see that there is no splitting of energy levels due to spin-orbit coupling. In my book it is said that spin-orbit coupling in helium is small and can be neglected but no further explanation is given. At the same time we do spin-spin coupling...

The coupling of the Higgs boson to the electroweak gauge bosons in the Standard model is given by $$\mathcal{L}_{\text{H-g}} = - \left( \frac{H}{v} + \frac{H^{2}}{2v^{2}} \right) \left(2M_{W}^{2}W_{\mu}^{+}W^{-\mu} + M_{Z}^{2}Z_{\mu}Z^{\mu} \right).$$ However, in Cliff Burgess' textbook 'The...

I want to couple white noise to a communication cable. I am using a 50/5A CT. My idea is to connect the noise in the secondary and to couple that noise into the cable. I want to know will my idea work? Does the CT what I am using will be suitable?

Hi there. I have an idea which is interesting. Let's suppose, we have AC generator which has capability of 100 KW and 100 RPM. And we have hydraulic motor which produces 500 RPM and 2400 Nm torque. Additionally, I attach 5:1 gearbox for reducing 500 RPM to 100 RPM for Ac generator. Please, share...

So I've read that at sufficiently high energies, photons will interact with each other rather than passing through each other in the usual ghostly ways. So in these situations, is constructive/destructive interference still possible? What is the threshold where it might stop, for practical...

In the electroweak sector, we define the left-handed Weyl fields ##l## and ##\bar{e}## in the representations ##(2,-1/2)## and ##(1,+1)## of ##SU(2) \times U(1)##. Here, ##l## is an ##SU(2)## doublet: ##l = \begin{pmatrix} \nu\\ e \end{pmatrix}.## The Yukawa coupling in the electroweak sector...

Homework Statement We consider a pendulum of length L hanging along the z-axis with a mass (taken to be unity) at the end, attached to an arm of length R free to rotate about the z-axis but restricted to the xy-plane. The system is completely described by the angle of the pendulum rod with...

Hi guys As per text... To match 10k with 500Ω a coil is used as an autotransformer tapped at point 3...now for a certain bandwidth and centre frequency what should be the value of Lp and Ls...?? How do I calculate it..?? and if the value of Ls and Lp is found out to be low then how could they...

Good evening everyone! Given that I have no experience in antenna physics or related areas, I'm studying a paper for a project I will be involved. It is an image sensor for THz e.m. waves and exploits micro-bowtie antennas to "capture" the signal and convert it through a standard CMOS imager...

I'm not clear on whether the coupling constant for strange to antidown is modified in the same way as for strange to down, i.e. multiplied by ##\sin(\theta_C)##. And are the coupling constants of interactions mediated by Z also dependent on the Cabibbo angle? And what happens if you have say a...

When I Google this, I find nothing straight forward. What is "force coupling" and what is "force decoupling"? Here are things I've found online that don't seem to match up. I see that a "force couple" is a way of applying force to a body so as to generate spin without causing translation...

Hi, I'm struggling to understand probability coupling. I have the following problem: Let X and Y each be uniformly distributed on the discrete set {1,...6} (i.e. the distribution of the roll of 1 fair die). (a) If X and Y are independent, what is Pr[X = Y]? (b) Couple X and Y so that Pr[X = Y]...

Hi, I'm working on a project of coupled simulation involving MCNP and Fluent, and having trouble with how to apply the pseudo-material method in cross section handling. Is there any related material or tutorial? Or, does anyone know the procedure of applying the method and what kind of files the...

Hi all , I'm confused about the definition of a perturbative coupling for QFT that it should be less than 4 ## \pi ## , because the higher order corrections comes of order ## \lambda / ( 4 \pi ) ## .. Now why QCD is not perturvative at low energy because the coupling constant approaches just 1...

Would it be possible to couple and electric motor to gas engine in series so both would increase the overall power.I currently building a twin engine car with two gas engines coupled together crank to crank like the old school twin dragsters.I would like to connect a large D.C. Motor in front of...

Why is the coupling constant of the Higgs potential not a constant, but is a running constant? In other words, ##\lambda (h) \sim \lambda_{0} - \frac{y_{t}}{16\pi^{2}}\text{ln}\big(\frac{h^{2}}{m^{2}}\big) + \frac{\lambda_{0}^{2}}{16\pi^{2}}\text{ln}\big(\frac{h^{2}}{m^{2}}+\cdots##, where...

How do I determine the value of a blocking capacitor for say this circuit: What I mean is, sure Cin must behave like a short circuit at working frequency, but something tells me there is more to the choice of a coupling capacitor than this.

I have an inquiry about how to make a system coupling between mechanical and electrical system in ANSYS program.

Hi everyone. I've got some doubts about the interpretation of the running coupling. I'll expose to you some of the results and comments i read in the lectures notes of my QFT professor. As an example, we are studying ##\phi^4## and the 4-point amplitude accounting for the next to leading order...

In Fluent, there are several 'pressure-velocity coupling' algorithms. Why are these necessary when, in many fluid mechanics textbooks, it is proposed that for incompressible fluids, an equation for Pressure can be found by taking the divergence of the Navier-Stokes equation, and inverting using...

Dear all, The Hamiltonian for a spin-orbit coupling is given by: \mathcal{H}_1 = -\frac{\hbar^2\nabla^2}{2m}+\frac{\alpha}{2i}(\boldsymbol \sigma \cdot \nabla + \nabla \cdot \boldsymbol \sigma) Where \boldsymbol \sigma = (\sigma_x, \sigma_y, \sigma_z) are the Pauli-matrices. I have to...

Hi all, I'm referring to the paper Chem. Phys. v.26 pp.169-177 y.1977 from Cederbaum, Domcke and Köppel where the expressions for linear vibronic coupling parameters are derived in second quantization notation. I'm stuck on the point, where the dependence of the fermionic ladder operators on...