Interaction Definition and 713 Threads

In what cases the force of the strong nuclear interaction (between nucleons or between quarks) is the force of repulsion? Thank you.

When looking into how particles decay, it seems that it will happen if there exists an interaction between the initial and final state, and if the final state has lower potential energy than the initial. (i.e. turning mass into kinetic energy) If this is true, how does a gluon turn into a quark...

Hello to all, Questions that I hope are not completely devoid of physical meaning. Firstly, about space. Let be a Hilbert space, in which we can by definition establish the existence of complete and orthonormal vector bases; and a Psi vector (state) that we write as a linear combination (a...

Let's take the example of an electron in of a hydrogen atom . It continuously interact with the proton of the hydrogen atom . Both the proton and electron are continuous interacting with each other. It is said that wave function collapse when it is being observed or observers interact with it...

I was over on the stack but got asked to move over here. https://physics.stackexchange.com/questions/804903/newtons-3rd-law-force-on-a-rocket I've been at it all day trying to understand what partner forces are and how you can have a change in force with regard to them, or why gravity is...

When a photon interacts with matter and diffracts, the photon seems to interact with the area of its wave front, determined by an aperture even if it is only one photon. But how far does it interact in depth? Does it always "feel" the whole crystal? Can we assume the photon is reflected by the...

Why isn't EM radiation attracted/repelled by a magnetic field?

I am sure this sounds silly but.. Between being emitted and interacting, a photon gives us no information as to where it is in space. If we know both where a photon was emitted from and where it then interacted, we can say that it travelled in a straight line. But we actually dont know. So in...

I'm having a bit of trouble with this exercise because, even if I understand the physics of the dipole-dipole interaction in an ideal classical system, I don't get to know how to approach this problem. I've got a few doubts about how this system would work. First of all, what would be the...

Hi, I wanted some clarification on the mechanism for how EM radiation interacts with standard glass, namely IR, visible and high energy (UV and X-ray). Looking online most sources seem to say the band gap is around 10eV. Since visible light is about 1-3eV visible light will be transmitted. IR...

I am trying to calculate the amplitude for a decay ##\phi \to e^+e^-## under a Yukawa interaction ##\mathcal{L}_I = -g\phi \bar{\psi}\psi## to one-loop order (with massless fermions for simplicity). If I'm not wrong, there are 4 diagrams that contribute to 1 loop, three diagrams involving...

Einstein showed (via general relativity) that spacetime is curved by mass, mass moves in relation to this curvature, and that gravitation arises as secondary effect. Why then are we looking for quantum gravity as some sort of mass<->mass interaction? Aren't the fundamental interactions better...

Looking to confirm: Does the hypothetical axion interact through weak and strong nuclear forces?

I am reading the following article on Kirkendall effect leading to the Formation of a hollow binary alloy nanosphere: a kinetic montecarlo study. I am unable to understand or find in references the reasoning to obtain equation (1):

I'm quite interested in the aforementioned topic, and would like to take a look at more literature about it, and to learn more about it, and would like to ask if you know more about it, or know interesting aspects about it, you can suggest the titles of the materials, or share the links to the...

I am trying to understand how one derives the dilaton monopole interaction. In "Black holes and membranes in higher-dimensional theories with dilaton fields", Gibbons and Maeda mentioned that one could obtain the dilaton monopole interaction as such: where the action is given by However, I...

My current understanding: The mass of alpha particle is approximately 7340.6 times higher than the mass of electron.in the gold foil scattering experiment the deflection of alpha particle due to electron is approximately zero. The reason that is given is that since the electron is much lighter...

Is the ##SU(2)_L## part of the SM asymptotically free like a typical non-Abelian gauge theory? I've been made to understand that confinement does not occur for ##SU(2)_L## because the spontaneous symmetry breaking scale is above the confinement scale, however I can't find any information on...

While researching S protein interactions I stumbled across a couple of recent papers studying the increased risk of developing Parkinson's after a Covid infection and the possible mechanism that plays a role there. https://pubmed.ncbi.nlm.nih.gov/34860005/ here is the full version of the study...

It was described that the thermal interaction changes average energy of each system by a different amount and the external parameters do not change at all in a thermal interaction. I do not understand how energy of a system changes without a change in external parameters.

In density functional theory (DFT), electron density is a central quantity. Because of this, we want to calculate electron - nuclei potential energy as functional on electron density. If we know how potential energy varies across space, we can calculate this functional with plugging particular...

Hello, I'm reading Feynman Lectures Vol II, and saw this "paradox" in section 26-2 (Figure 26-6), where two orthogonally moving charges can be shown to have unequal action and reactions. Later in Chapter 27, the explanation was given briefly citing field momentum. I tried to prove this...

How can a quantum object interact with its environment before it has any definite properties? It seems like a ‘chicken and egg’ scenario to me. I can’t see how anything could interact with a quantum object which has only potential properties (what is there to interact with?), yet if I’ve...

I was taught that photons ( non-ionizing at least) never interact. So Its really bugging me that most info on faraday effect invokes B field as the cause of ( for example) rotation effects. Since EM-waves (IE Photons) themselves propagate a (oscillating) Magnetic field through infinite space...

I'm new to relativistic quantum mechanics and quantum field theory and was trying to learn about the Dirac equation. Unfortunately, I got a little stumped by the interaction between matter and antimatter. It seems like the time derivative of matter is dependent on the spatial derivative of...

I can understand what happens with the conductor... (induction effects). But how can induction happen in insulators ? Is it due to the the induced dipole moment?

What is the reason to unite weak and electromagnetic interaction

When we learn about the scattering of a particle, the context is usually a charge shooting towards a Coulomb potential. With some assumptions, we can derive the scattering cross-section pretty reasonably. Therefore, the scattering cross-section of different elements in X-ray spectroscopy is...

Hi guys. I work with statistichal mechanics, applying classical spin models, as Ising model. I'm trying a collaboration with a colleague that works with first principle calculations. Does anyone know how to calculate the exchange interaction and anisotropic constant (of the Blume-Capel model)...

EDIT: I'M SO DUMB! I can't believe I can't multiply matrices together. Of course the result is not zero, the matrix on the left will be: $$ \begin{pmatrix} 0 & e^{i\omega_at/2}\\ e^{-i\omega_at/2}&0 \end{pmatrix} $$ So i was solving problem 3 from...

The term for the electromagnetic interaction of a Fermion is ##g \bar{\Psi} \gamma_\mu \Psi A^\mu##, where ##g## is a dimensionless coupling constant, ##\Psi## is the wave function of the Fermion, ##\gamma## are the gamma matrices and ##A## is the electromagnetic field. One can quite simply see...

Now from physics I read that photons don't interact with one another normally, at higher energies they might through pair production but that is besides this point. So this means that for example if we have multiple sources of EM radiation like say multiple sub pixels within a screen then each...

Maybe we could use (1) uncertainty principle $\Delta E \Delta t = \hbar$ and get $\Delta E$ from the spetrum. Or (2) forced vibration model, then get the damping factor $\gamma$， and get $Delta t = frac{1}{\gamma}$

This has been a big annoyance for me for a while. I do some GUI development and programming for some of the Manufacturing Test Fixture programs that I develop, so I'm sensitive to making GUIs intuitive and easy to use. But with many PC and phone interfaces (mainly browser-based), the program...

What is a boundary and how can boundary interactions be used in echolocation and examining internal body structures?

Light is propagating electric and magnetic fields. The electric field interacts with electrically charged particles, e.g. electrons. Is there a corresponding magnetic interaction?

With free part L=-½(∂Φ)^2 -½m^2 Φ^2 and interaction term L=½gΦ^2Any help would be appreciated, thank you.

I'm a college grad, but not in science or physics. I'm useless on the math. However, I have a solid layman's understanding of double slit experiment as well as the delayed choice quantum eraser . I also have a layman's understanding of quantum physics via reading some mainstream science...

I am trying to get a foothold on QFT using several books (Lancaster & Blundell, Klauber, Schwichtenberg, Jeevanjee), but sometimes have trouble seeing the forest for all the trees. My problem concerns the equation of QED in the form $$ \mathcal{L}_{Dirac+Proca+int} = \bar{\Psi} ( i \gamma_{\mu}...

Hello, I am looking for a comprehensive theoretical book or article related to the hole-phonon or exciton-phonon interaction in semiconductors. To be more precise, what I am looking for is: 1- Second quantization for the phonons (especially acoustic phonons) 2- Derivation of the Hamiltonian...

What is the difference between Electron-electron interaction in metals and semiconductors? And for which one it is stonger?

I am doing a difference-in-difference analysis on a set of survey data for a health education program and I need to find statistical significance for the difference-in-difference estimate. I know that I find this using a regression. I need to use a regression in a mixed logistic model including...

Are there any plausible semiconducting or superconducting devices which would show clear parity violation? Electrons in matter are governed overwhelmingly by electromagnetic interactions. Electron-electron, and electron-nuclei. However, there is in principle some weak interaction. Elastic weak...

For an electron in the orbital characterized by ##l=0## we have ##j=0\pm1/2## and so ##J^2=j(j+1)## gives ##J^2=3/4## and ##-1/4## (normalized to ##\hbar^2##). Finally, ##L.S=1/2(J^2-L^2-S^2)## results in ##L.S=0## and ##-1##. However, according to ##L.S=l_xs_x+l_ys_y+l_zs_z## we find ##L.S=0##...

We feel that Earth pull as to the ground but is Earth accelaritng up "in some way" so gravity is also inertial force?? I read that we still don't understand what is gravity...

From the density and the mass we can find the volume using d=m/v <=> v=0.06 m^3. Since we consider the astronaut a sphere we find his radius using V(sphere)=4/3*π*R^3 =>R=0.242m. Now we can calculate the surface area with the formula A=4πR^2=0.735m^2. The energy absorbed will be i suppose equal...

Why photon interact weakly with their environment over long distances ?

I am trying to calculate the interaction energy of two interpenetrating spheres of uniform charge density. Here is my work: First I want to calculate the electric potential of one sphere as following; $$\Phi(\mathbf{r})=\frac{1}{4 \pi \epsilon_{0}} \int...

What I have tried to do is to separate the exponential of the unitary transformation operator to the interaction picture into three different Hilbert "subspaces" like: $$e^{i\frac{H_0}{\hbar}t}=e^{i\omega_m \hat{b}^+\hat{b}}\otimes e^{-i\hbar\nu|1><1|} \otimes e^{-i\frac{g}{\omega_m}|e><e|t}$$...

Hello, If you have an appropriately oriented conductive ring in a constantly changing magnetic field, current will flow in the ring. There will also be a magnetic field associated with the current in the ring. I understand (maybe ... ) that the current is due to the electric field which is...