Interaction Definition and 713 Threads

Homework Statement A 0.70-kg basketball dropped on a hardwood floor rises back up to 66 % of its original height.If the basketball is dropped from a height of 1.4 m , how much energy is dissipated in the first bounce?( answer =3.3J). How much energy is dissipated in the fourth bounce? Homework...

Homework Statement A 0.70-kg basketball dropped on a hardwood floor rises back up to 66 % of its original height. If the basketball is dropped from a height of 1.4 m , how much energy is dissipated in the first bounce? Homework Equations U=mgy The Attempt at a Solution U=(0.70)(9.8)(1.4)...

Homework Statement Find the interaction energy ( ##\epsilon_0 \int \vec{E_1}\cdot\vec{E_2}d\tau##) for two point charges, ##q_1## and ##q_2##, a distance ##a## apart. [Hint: put ##q_1## at the origin and ##q_2## on the z axis; use spherical coordinates, and do the ##r## integral first.]Homework...

Hello everyone. What measurements have been done of the Higgs self-interaction? If nothing has been done yet, what are the relevant groups and research articles describing the progress of work in this direction? If this has been done, I would love to know the references. Thanks!

I am trying to derive the k dot p formula with the spin orbit interaction term included. I am having some trouble. I insert a bloch wave function multiplied with an unspecified spinor. But how do I treat the cross product term that comes from the SO and what is the effect of the pauli matrix...

As I understand it (e.g. from discussions around the Fermi field theory of the nuclear force), a spin 1/2 particle can emit a spin-1 particle and simultaneously flip its spin (say, spin +1/2 -> photon +1 & spin -1/2); but how does this work with spin-2 particles? Does it need to emit pairs in...

Hi all, I've read a number of posts on virtual particles (including one of my own), but I'm still confused about one aspect - the interaction between real and virtual particles. Say we have an electron moving from position A to position B. As the electron moves, there should be virtual...

Hello. Does anyone know a good book explaining light and semiconductor interaction? Namely, the processes that take place inside the material.

Homework Statement [/B] Thin rod of length l is placed with one of its ends at the center O of the (thin circular )ring of radius R as shown (Figure 1), perpendicular to the plane of the ring. The rod is charged with total charge Q that is distrubted along the rod's length with linear charge...

Homework Statement In electromagnetic interactions, the force carrier is the photon, and it interacts with anything which has electric charge. Electric charge can be represented by the integers on a single number line and photons themselves carry no electric charge. (a) In the case of the...

How a potential well is formed? Can mass of a wave creates a potential well?

klotza submitted a new PF Insights post The Interaction of Sound and Light Continue reading the Original PF Insights Post.

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...

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

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 +...

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...

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...

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...

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...

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...

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

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...

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...

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...

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}=...

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?

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...

[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...

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

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...

Consider six electrons allocated in three orbitals in a closed shell restrictred HF ground state determinant. Now, consider three excited states: How many CI configurations can result from this system when only two electrons are excited per configuration? Is it true that there are 9 * 9 + 36 =...

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...

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.

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...

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 ##...

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?

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...

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...

I have come across the paper attached in which a 1D fluid piston is modeled. I have question on the boundary conditions (BCs) of the system. Essentially, the problem consists of a fluid chamber in contact with a spring (a mass -spring system). ALE is used to move the mesh. I am not certain...

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...

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...

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...

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...

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...

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...

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...

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...

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?

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...

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.