Interactions Definition and 281 Threads

In GR, if two massive objects distort spacetime, are the effects still "equal and opposite" in some sense? In what sense? It seems that for "equal" to hold, the equations of GR must force the effect of one mass, A, on spacetime at the location of another mass, B, to equal the converse (the...

TL;DR Summary: Book: Neoclassical Theory of Electromagnetic Interactions - A Single Theory for Macroscopic and Microscopic Scales I've found the book of Babin & Figotin: Neoclassical Theory of Electromagnetic Interactions - A Single Theory for Macroscopic and Microscopic Scales. I like their...

1.How is that possible for us to say that a non-interacting microscopic particle can have numerous values of a physical parameter in a given instant? the mixed state of a microscopic particle is simply the probability distribution of the particle having those values of a given physical parameter...

Hello, I understand the concept of multicollinearity: when dealing with a multiple regression model with two or more independent variables, some of the independent variables may be pairwise correlated. This does not affect the model in terms of its predictive results but it impacts the...

Hello, when reviewing the types of chemical bonds i was a little bit confused about van der waals interactions, in the definition we talk about momentarily disproportion of electrons that provoke a dipole , and then i read that also include hydrogen bonds . I am a bit confused about van der...

While this was inspired by another thread, I think the question is different enough that it can be asked separately. It's also more suited to this forum than the forum where the question that inspired this one was asked. Wiki gives four possible interactions for interactions of gamma rays with...

Will the presence of attractive interactions between gas molecules raise or lower the molar Gibbs energy of a gas relative to its ‘perfect’ value? I would think that these attracting forces result in a lower energy state. A decrease in the energy state implies a decrease in the enthalpy. A...

LJ potential is an empirical potential function used between 2 neutral atoms. Is there any classical/empirical potential for electron-ion interactions as well? Different from Coulomb potential, this one if any should be able to capture the mechanism of a valence electron leaving an atom and of...

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...

Hello! I recently came across the Hanle effect, which is a reduction or increase in the polarization of the emitted light from an ensemble of atoms as a function of an externally applied magnetic field. Not so long ago I heard about the Faraday effect which is a rotation of the polarization of...

So first I looked at where the image of the fish appeared to be when it went through the water surface. since we can assume the water is flat, R is infinity, so n1/p=-n2/q. plugging in the values (n1=1.29, n2=1, p=3.5) I get q=-0.3686. So the image of the fish appears at 0.369 above the...

I have read that if the exchangeparticle of an interaction has even spin then the force between them is attractive if the charge is equal (gravitation) and repulsive if the charge is not equal. Is this wright?

This is not really homework assigned to me but I wasn't sure where to post this. I'm trying to work through the book "Quantum Field Theory for Gifted Amateurs" by Tom Lancaster. I'm doing the questions on Chapter 19 to understand how to draw Feynman diagrams and work out their amplitude. One of...

If there are no flavor changing z0 weak interactions, how do we even know that the particle exists? I thought that we could only tell which particle was exchanged by the particles it decays into. Is this wrong?

We know that energy can be converted from one for to another , but how does it do that? How exactly does energy interacts with the quantum particles or with strings for that matter?

https://phys.org/news/2018-04-dark-interactive.html "Observations using the Hubble Space Telescope appeared to show that a galaxy in the Abell 3827 cluster - approximately 1.3 billion light years from Earth - had become separated from the dark matter surrounding it. Such an offset is predicted...

Draw graphs showing how interaction energy depends upon the relative orientation of two dipoles if (i) p1 is parallel to r, (ii) p1 is perpendicular to r. I've done the first part and found the interaction energy as UInt = 1/(4*pi*epsilon0*r^3)*[p1.p2-3(p1.r^)(p2.r^)] which I know is correct...

Hi, I am looking for a book about the unified electroweak and strong interaction theories, dealing with the following: Gauge Theories. Intermediate Vector Boson Theory. Gauge Theory of Weak Interactions. Spontaneous Symmetry Breaking. The Standard Electroweak Theory. I've basically quoted...

I think my main question is pretty much summarised in the TL;DR. I have another related question: Is it possible for one to "create" two fermionic particles of the same charge but a different spin (using creation operators ## \hat{a}_{ \downarrow , + }(x,t)\hat{a}_{ \uparrow , + }(x,t) |0...

How strongly magnetic is a compass compared to a magnet? If many compasses are put near a magnet, is it possible that the compasses are so strong that their orientations are affected by not only the magnet but also other compasses nearby?

Since supplement sales in North America are multi-billion dollar enterprises and many people take one or more supplements, this is a useful way to find out if there is a problem with a supplement interacting with a food or a drug. Supplements are sometimes prescribed, like Coenzyme Q10 for...

So I am reading a book "Fundamentals of Nuclear reactor physics" by Elmer E. Lewis On page 37 it talks about neutron interactions. some sentences I feel are left a bit short so let me rephrase here and hopefully get a clear answer. We have a neutron with a given kinetic energy and bunch of...

The interaction of neutrinos should be proportional to the amount of material that it goes through. If i want to calculate the number of interactions that i could expect when a neutrino beam go through different materials, the first thing that comes to mind is the nuclei of the targets, as the...

According to wikipedia, the strong equivalence principle states “the gravitational motion of a small test body depends only on its initial position in space time and velocity, and not on its constitution, and the outcome of any local experiment (gravitational or not) in a freely falling...

Does one neutron or more than one make different when they interact with the nuclei? what is the result that could happen if one neutron or neutrons hit the nuclei? I'm not sure but I think the neutrons are the most confusing particles to deal with. I wish you guys can help me Thanks

Usps=1/2(1.8x10^6)(0.03)^2=810J Ke=1/2mv^2=1/2(0.05)(300)^2=2250J I don't know how to take it farther than this, or if this is the correct way to start the problem. If this is correct, would it be correct to assume that the bullet does penetrate the creature because Ke overcomes Usps?

I read in Greiner Field Quantization that parity only has meaning in interactions. Did I misread or not understand something correctly?

I am studying QFT from the book A First Book of QFT. I am currently in the chapter of QED. The authors have written down the interaction Lagrangian for QED. Thereafter, they have taken a special case of the electron, and written down the normal-ordered interaction Hamiltonian for this case...

A stationary closed system such as an air in a room or a water in tank can exchange energy with its surroundings, such as receiving heat, fan work, electrical work, shaft work. These energy interactions cause a change in the total energy E of a system. This total energy can be comprised of...

Hello! As far as I understand, in QFT the interaction between particles is mediated by the exchange of a boson. When doing calculations, one assumes that you have 2 free particles coming in, they interact at a point by exchanging a boson and then they propagate again as free particles, and this...

In the context of popular science literature, when antimatter comes into contact with regular matter, what happens is described as "annihilation" or "they annihilate". It is also rumored that 100% of the mass in the constituents is converted to energy. The rumor would also suggest that there...

I have some questions about forces acting between electrons (-1 charge) and up quarks (+2/3 charge). I did attempt to make sure its a valid line of questioning by privately asking mfb... & I'll ask all the questions up front so as not to annoy the moderators with my follow up questions. So...

Dear community, I am Pedro de la Torre, now doing my PhD on Cosmic ray propagation. Now, I have started to study reacceleration due to interactions of CR with plasma waves. My problem is that I do not find neither a good book or any kind of review with a detailed demonstration on the...

Hello! I am reading about HL-LHC upgrades and they introduce ##\beta^*## which is directly related to the transverse size of the beam. Now they say that in order to increase the luminosity you need to reduce ##\beta^*##, which makes sense as a reduced volume means higher particle density so...

Hello, Currently studying electromagnetic radiation and ionisation and a bit stuck on a concept. From what I think I've understood, an electromagnetic photon enters matter, and if the energy is > 10eV it will displace an electron causing it to ionise (and therefore moving out of the atom). This...

As far as I know, the total cross-sections of the following hadron interactions are well described by a single Reggeon trajectory and a single Pomeron (soft Pomeron) trajectory. ##K^-p: (11.93s^{0.0808}+25.33s^{-0.4525})mb## ##K^+p:(11.93s^{0.0808}+7.58s^{-0.4525})mb## ##\bar...

Hello, new here with lots of questions and minimal knowledge of physics. If I understand this correctly, when spontaneous emissions take place within a LASERs resonance chamber, they are not of the desired frequency nor are they paired with other coherent photons. So are they still desirable in...

I have a not-very-well formulated question about the interaction picture of QFT. I understand that, in an interaction picture, particle numbers are not well defined (except as t goes to infinity and you're back at free fields). However, at the very least, in an interaction picture, a field...

So I'v been told that this interaction : e- + e+ = mu- + e+ isn't allowed. Why not? I thought maybe because the mass of the muon is so much bigger, so would violate energy conservation, but the electron/positron could be moving relativistically and thus have enough energy. Apparently the...

I'm a complete rookie in this field so please correct me where I go wrong, I just really want a better understanding of this subject. So as far as I am aware, mass causes the space surrounding it to curve or bend. What I want to know is how much does it bend the space? is the bending of space...

I always struggle to know which force (strong nuclear, electromagnetic, weak, gravity) is responsible for an interaction. For example, pi+ + pi- = neutron + pi0 I would say its strong force responsible, because quarks are involved. But the pions are also charged, so how do I know it's not...

Hi there. I was wondering if there are classical theories for the weak and strong interactions. I am relatively new to physics so I do not know the answer. Also, is there any classical theory for the electroweak interaction? Thanks in advance.

Homework Statement Let us consider a fully connected Ising model with four-spin interaction in a transverse field Write the mean field Hamiltonian. Homework Equations none The Attempt at a Solution I know that the mean value of the product of two spins is equal, in the thermodynamic limit...

Hi everyone. So I was studying and they say there is a force function (and a potential energy, I suppose) for every fundamental interaction. So, they always show the gravitational and electromagnetic force/potential energy functions for these, and they always mention the other two (plus the...

I am about to teach some of an introductory course for bachelor students in the field of medical physics. More specifically the topic "Photon and charged particle interactions with matter" in respect to radiation therapy (again, medical physics). I know there are a lot of topics within radiation...

Has anybody seen any neutrino interactions on video on the Internet where you can see the interactions that have taken place in a neutrino detectors? I know that the interactions in most neutrino detectors is spaced out over time (that come from the same location), but it seems to me that over...

Homework Statement [/B] I have created a very simple Rube Goldberg device in Algodoo, and I need to analyze 3 correlating steps within it, using physics descriptives and equations. My primary focus is the ball as it hits the windmill, which I need to describe and calculate its velocity at that...

After solving a homework problem, I realized I don't know what to do when there's a dipole and a point charge but the distance from the charges in the dipole is greater than the distance from the center of the dipole to the charge. As my homework problem stated, with a little context added...

" But in a study published today in Science, researchers working at Oak Ridge National Laboratory (ORNL) detected never-before-seen neutrino interactions using a detector the size of a fire extinguisher. " From...

I am finding references and good books for the conceptual understanding of Breit Interactions. Are there any books which specifically include the topic? The related topics explaining the formulation Breit Hamiltonian and its involvement to the correction to the atomic structure calculation are...