Particle Definition and 1000 Threads

How would an observer's particle horizon and coformal time be affected by her traveling at very near c (relative to the CMB), both in and opposite the direction of travel (ahead and behind)? Also, how would Hubble expansion be impacted in her frame of reference? (I apologize in advance for...

Taken into account the transverse nature of the wave, I deduce the particle must move of harmonic motion from maximum amplitude ##A## to negative maximum amplitude ##-A##. The period ##T=\frac{1}{f}## is equal to the time in which a particle travels a distance ##d=3\cdot A##. I then approximated...

Hi, I'm trying to prove a wave equation of particle in a box situation. In many solutions, they used a equation like Eq = Asin(kx)+Bcos(kx). Instead, I want to prove using Eq = Aexp(ikx) + Bexp(-ikx). So, this is my solution. However, the original (well-known) solution is without i. (psi =...

What does the phrase “Due to Lorentz invariance, only the Higgs particle can have a non-zero expected value in a vacuum” mean?

Here are the results from the python code: Odd results: Even results: I tried to solve for energy using the equation: I substituted the value for a as 4, as in the code the limit goes from -a to a, rather then 0 to a, and hence in the code a = 2, but for the equation it would equal to 4...

Open question: Can we be sure that a quantum model double slit doesn't create a carrier interference pattern around the slits, in the fields, already there? Relativity is such a big deal in physics but so many models only consider seemingly weird quantum particles going through normal classical...

Some background, I am an undergraduate electrical engineering student with a knack for physics. I plan to attend graduate school for physics but for the meanwhile I've only taken an undergraduate course in QM mechanics, which used griffith's book, and a modern physics course, which covered some...

This problem really confused me, since I can't get the link between particles emitted(alpha and beta, but which are the differences between those?) and changes in mass and atomic number of the isotope. For this one, I can't really show you my attempt since there ain't one...

I think Physics should not be weird, there have to be explanations or it might mean we don't understand enough.

Starting with finding the probability of getting one of the states will make finding the other trivial, as the sum of their probabilities would be 1. Some confusion came because I never represented the states ##|\pm \textbf{z}\rangle## as a superposition of other states, but I guess you would...

I just realized I'm having a problem in understanding this. So let's take an example the CMB is around 160 Ghz and the blackbody temperature within this frequency range is 2.7K which is rather cold as it is close to absolute zero. Then let's take another example, Iter plasma will achieve about...

Hi! Instead of just describing my procedure and all my derivations, I really just want to ask if my approach makes sense (actually I have 2 options) to calculate the maximum energy. I am considering c=1 and the problem suggests to consider the neutrino massless: For the first decay, ##Z...

At first I take the uniformly distributed charge and then divide it by the area of the carpet to get the surface charge density σ -10E-6 C / 8m^2 = σ = -1.25E-6C/m^2 Then I divide the surface charge density by 2e0 to get the electric field strength caused by the infinite plane...

It was a long time ago I did these kind of problems so I’m a bit rusty. The only thing I can think of is divide it up to two parts one x and one y. In y the acceleration is sin(a)*9.82? Then put that in the equation and solve for t. In x the there is no acceleration so the formula is x=V0*t, I...

qvB=mv^2/R R=mv/qB= p/qB ! As you can see, the difference between this relation and the relation in question is in 'c'. Maybe my way is wrong. Maybe I should get help from relativity because the speed of light is involved here. Please help. Thankful

Hi In the book, "Why does E= mc2" by Cox and Forshaw, while discussing time dilation, the example of a muon is given. The authors explain that muons when circulated in the 14 m diameter AGS facility at Brookhaven at 99.94% of the speed of light, its lifetime is increased from the value of 2.2...

Can anyone give a layperson guide to what the curvaton is ? There is a description of it in wikipedia. but It is not clear from the article why it was postulated. Is there any independent reasons for thinking this curvaton field exists other that to generate the right type of spectrum for...

$$\hat{T}_{\mu v}(x)=e^{i\hat{P}x}\hat{T}_{\mu v}(0)e^{-i\hat{P}x}$$, so $$\bra{\overrightarrow{P'}}\hat{T}_{\mu v}(x)\ket{\overrightarrow{P}}=e^{iP'x}\bra{\overrightarrow{P'}}\hat{T}_{\mu v}(0)\ket{\overrightarrow{P}}e^{-i\hat{P}x}$$ Now, $$\partial^{\mu}\Phi=\int\frac{d^3 k_1}{2\omega_{k_1}...

Good afternoon, I have a question regarding this derivation that I'm covering in Thornton & Marion's "Classical Dynamics of Particles and Systems". In it, we're covering the most basic equation of motion for a particle falling in a medium. I understand the process of starting with Newton's 2nd...

I'm making a mistake somewhere, I hoped someone could point it out? Say a particle of mass ##2m##, initially at rest, disintegrates into two particles of mass ##m## that move at ##v_{1x} = v## and ##v_{2x} = -v##. Then we switch to a frame moving at ##-U## along the ##x## axis, so that$$v'_{1x}...

On page 41 for the spontaneous disintegration of a particle into two, Landau states the total momentum in the C system is zero. On page 43 for the disintegration of many particles into two, Landau states: In the C system... every resulting particle (of a given kind) has the same energy... I...

I have heard that if you could make a sheet of material thinner than a wavelength representing a particle and fire particles at it, that particle might be detected on the other side of the sheet material when you try and detect it due to Quantum Tunneling i believe. Does that mean that it's...

Hello, I was glazing through what I would consider an advanced physics textbook and I saw this image. It is a schematic picture of an alpha-particle in a field of an atom. Now, can someone get me started on what (and why and how) is going on in it? Especially with the fraction with pi.

This seems like it should be an easy and obvious thing to look up, but I had the hardest time finding it. Is there any graph which shows, as I increase the beam energy of a particle accelerator, what particles can be produced at each energy? Just looking for something ballpark here. Obviously...

In the example above, the authors claim that when ##r=r_0e^{\beta t}##, the radial acceleration of the particle is 0. I don't quite understand it because they did not assume ##\beta=\pm \omega##. Can anyone please explain it to me? Many thanks.

When a particle is observed, an interaction must happen between it and the measuring apparatus. But, this interaction mostly (if not always) leads to the loss of the particle, and hence, can't be used again to do the same experiment or different experiments. I know that particles are identical...

I'm curious whether we can confirm that hadrons don't like hadrons? https://iopscience.iop.org/article/10.1088/1742-6596/1512/1/012021

Hi Pf i am accustomed with the action $$mc \int ds $$ for relativistic particle. i found a paper by Andrew Wipf with another lagrangian. please look at the beginning of chapter seven (7.1) Is it possible to deduce from it the shape of its trajectory? I have a lot of question about this chapter...

Suppose you are analyzing this image. The question to answer is: Explain why the alpha particle's path has a larger radius than either of the beta particle paths. Justify your answer using either momentum or charge-to-mass ratio. When you are answering this, suppose you know that , in...

For calculating minimum E, I have n = 1, L = 2a & ψ = 2. But I am not getting how to exactly find its value. Please help me !

I can only find papers relating to how they've used the model but nothing about the model.

I've marked the right answers. They mainly indicate at power carried by the particles being zero, and here is my doubt- why should it be zero? Shouldn't it have some definite value? I do understand that the kinetic energy is max at the y=0 and potential energy is max at y=A, but I don't know...

This is diverted from the Classical Physics forum. My first approach was this: the force ##\vec{F}## can be written in polar coordinates as ##\vec{F} = F \hat{\theta}##. It follows that ##F_{\theta} = ma_{\theta} \implies F = m(2\dot{r}\dot{\theta} + r\ddot{\theta})##. This result also agrees...

What forces act at air particle at curved streamline, looking from inertial and non-inertial frame of reference? (show free body diagram)

So I understand that time is now part of the four vector, and so dividing delta X by delta t (time according to me), would produce just c as the first dimension of the vector, which gives us no intuition as to how fast time is moving for the observer, so is not useful. I understand why we...

hello all : looking for books to read in this times ,undergraduate level mostly , but i have some problem finding good ones for introductory elementary particle physics other than griffths and for special relativity any recommendations

There's a constant magnetic field B. If a particle is acted on by a force qv*B (* cross) only, and the initial velocity v0 is normal to B, is the motion certainly a circular one (for any m, q, v0)? mv''=qv*B If one solves this equation (vector), it doesn't seem obvious.

From the probability density plot why it is max at the centre of the box...e.g probability to find the particle per unit le gth is max. at the centre of the box??why not at any other position??

What I need help with is how I would start.. I can say p(X, Y) = (1,0) = 1/4, and same for the other 3 coordinates. P = 0 for all other coordinates. This doesn't give me anything to work with though. C(X, Y) = E(XY) - E(X)E(Y) What is XY? I don't even know what X is.

I seek an explanation as to how a particle can be its own anti-particle. I would think the instant such a particle comes into existence, it would self-annihilate.

The equation of motion can be integrated w.r.t. ##t## since ##\frac{d}{dt} (\mathbf{r} \times \mathbf{B}) = \dot{\mathbf{r}} \times \mathbf{B} + \mathbf{0}## $$\int (q\dot{\mathbf{r}} \times \mathbf{B} + m\mathbf{g}) dt = \int m\ddot{\mathbf{r}}(t) dt$$ $$\frac{q}{m} \mathbf{r} \times \mathbf{B}...

I'm falling at the first hurdle here; the time independent Schrodinger becomes $$-\frac{\hbar^2}{2m} \psi''(x) - \frac{\hbar^2}{m}\text{sech}^2(x) \psi(x) = E\psi(x)$$ $$\left(-\frac{d^2}{dx^2} - 2\text{sech}^2(x) \right)\psi(x) = \frac{2mE}{\hbar^2}\psi(x) = \mathcal{E} \psi(x)$$...

I honestly have no clue where to start, any help would be great.

The movement in the z-direction is easy to solve for, as it's only affected by the gravitational force. However, if there's a magnetic field pointing down along the z-axis, the particle is going to be accelerated along the y-axis (F=q*v *B). The force is always going to be perpendicular to the...

Once I know the Hamiltonian, I know to take the determinant ##\left| \vec H-\lambda \vec I \right| = 0 ## and solve for ##\lambda## which are the eigenvalues/eigenenergies. My problem is, I'm unsure how to formulate the Hamiltonian. Is my potential ##U(r)## my scalar field ##\phi##? I've seen...

Hi, I have attached the question to this post. I understand on the process on getting to the answer in that you use $$\arrowvert 2, 2\rangle=\arrowvert 1,1\rangle \otimes \arrowvert 1,1\rangle$$ and apply the isospin-lowering operator to obtain $$\arrowvert 2,1 \rangle$$. Then I understand you...

Hello, I have answered the question below but would like some advice on whether I can improve my answer or if anyone is able to check whether I have made any mistakes ? i. 1 V = 1eV in a 1:1 relationship, therefore; 6.5 TeV = 6.5 TV = 6.5 *10^12V ii. E=W W=V * Q Q=number of particles * charge...

[Moderator's note: Spin off from previous thread due to topic change.] Just as an aside and not related to the OP, would a real particle with negative mass inside the event horizon follow the runaway motion? Would it be ejected?

But yet again my text says that option 4 is correct.

I am confused whether for electron I have to use rest mass energy (moc2 + 0.8 MeV) or just 0.8 Mev for calculating E. Also how do I find minimum density of a neutron star using above data ? Please help !