Particle Definition and 1000 Threads

A solution of equations of motion for charged particle in a uniform magnetic field are well known (##r = const##, ## \dot{\phi} = const##). But if I tring to solve this equation using only mathematical background (without physical reasoning) I can't do this due to entaglements of variables...

I've heard it from my classmates that particle physics is just like botany or when physics meets taxonomy. There is even a quote from Enrico Fermi about this "If I could remember all names of these particles I'd be a botanist" I just want to know how true is that.

I'm just curious, is it possible to simulate a quantum particle (so that it is exactly like a real quantum particle) merely using a classical computer? When something is simulated on a classical computer, it's not really actually there, what you see on the screen is just pixels lighting up. The...

I calculated the complex conjugate of both the given wavefunctions. For ψ1: ∫re^((-2)mod(r)x)dx=1 with upper limit ∞ & lower limit -∞. I replaced the upper and lower limit after breaking down the function inside integration as follows- r*∫e^(2rx)dx from -1/r to 0 and r*e∫e^(-2rx)dx from 0 to...

I thought it would be a good idea to pretend that the walls are stationary and that each time the particle hits a wall, it gets a velocity addition of the velocity of the wall it’s hitting. Using this I ended up at the formula V = initial velocity of particle + n(velocity of left wall) +...

Has there been an experiment where 2 particles that are entangled are measured at the same time? If so what was the result? Can any observer occupy the same frame of reference down to an electron? Don't we all exist at different times based on our frame of reference so none of us can share the...

I understand that you need to integrate f(x), and the negative of that is U(x). But the last part of the problem says "Clearly state any assumptions you make." And the answer is just the antiderivative of that f(x) without any constant from integrationHow does that make sense

Hello, I'm working on a project. I need to understand every equation in a paper. I need to calculate the spatial derivative of G (d/dR), a two-particle Hamiltonian. However, G is a function of P- the density matrix and P is a function of R. Is it a "special derivative"? Here is the attached...

In QM a free micro particle with definite momentum has not definite positions.But why does in classical physics a free particle with definite momentum still have definite positions but not blurred as in QM?(Because we can deduce Classical Physics from QM)

Hello everyone, I am working on the following problem: I would like to determine the invariant Matrix element of the process ##\psi\left(p,s\right)+\phi\left(k\right)\rightarrow\psi\left(p',s'\right)+\phi\left(k'\right)## within Yukawa theory, where ##\psi\left(p,s\right)## denotes a fermion...

Here is my attempt at a solution. The thing I am not sure about is the final result of the Shrodinger equation and the n-values that are offered? Did I make a math mistake? Thank you so much for reading through this!

Summary: Can a particle accelerator accelerate gaseous fuel? Does space-time differ for detonating ionized fuel moving near the speed of light within a magnetic field such as a particle accelerator?

Hi folks, I'm trying to get a grasp on some of the basic concepts of QFT. Specifically, I'm trying to picture what are the actual fields of QFT and how they relate to wavefunctions. There are already many helpful posts about those concepts, here and in other places, but some points are fuzzy...

In Landau-Lifsits's book about non relativistic QM it is said that if I have a particle described by a plane wave ##\phi = e^{ikz}## (I think he choses the ##z## direction for simplicity) the wave function after the scattering event is (far from the scattering event) $$\psi \approx e^{ikz} +...

Proton is going towards the ##\alpha## particle. So, I am thinking of using the conservation of energy as the initial kinetic energy of the proton is known and initial interaction potential energy is zero. But, we don't know the kinetic energies of proton and ##\alpha## particle when they are at...

Well, I tried plugging the data in the formula. I know that ##\vec a_b = 0; \vec \omega=3 rad/s ; \vec r## can be calculated using trigonometry. Then I also know that ##v_{relx}= 10 cm/s##, ##a_{relx}=15 cm/s^2##, ##\vec {\dot{\omega}}=-10 rad/s^2##. But how do I get ##v_{rely}## and...

I know that it has a cause! It happens to make the nucleus more stable. But some say it has no cause. I am confused actually.

Note: I don't know if this actually qualifies as advanced physics, it probably doesn't. It's a review problem in a non-introductory class but I can't solve it so... Beginning with the hint, I know that the x and y components of velocity don't change when the particle moves from z < 0 to z > 0...

Ive included question and thinking in the attachments. Many Thanks

The final answer should have a negative b^2⋅r(dot)^2⋅r term but I have no idea how that term would become negative. Also I know for a fact that my Lagrangian is correct.

I start out by substituting rcos(Θ) and rsin(Θ) for x and y respectively. This gives me z=(b/2)r^2. The Lagrangian of this system is (1/2)m(rdot^2+r^2⋅Θdot^2+zdot^2)-mgz. (rdot and such is the time derivative of said variable). I then find the time derivative of z, giving me zdot=br⋅rdot and...

I've got the solution to the question but I just need more detail. I can't work out the first step of the solution to the second step. That should read, I don't know what they multiplied ih-bar by to make it (i/h-bar)^2?

The particle is moving under a force field with the potential energy equation described above. I find it logical that Newton's Laws can be used as in the question itself it is stated that the velocity is quite small and we could approximate its subsequent motion via the notions of Classical...

We have been taught that the there is no experiment designed to detect wave and particle nature of light simultaneously. Also, that light propagates by the virtue of its wave nature and interacts by the virtue of its particle nature. let us take an electron beam passing through two slits...

I have the following problem: So, I know the following: ##q_1 = -e## ##q_2 = -e## ##q_4 = -e## ##q_5 = e## ##e = 1.6*10^{-19}## ##k = 9*10^{9}## Now, I can get the current ##F_{net}## of particle 5 with this information: ##F_{net} = (F_{3} - F_{1})\hat i + (F_{2} + F_{4})\hat j## ##F_{1} = k...

Here is picture. Answers is A. My attempt was that I thought if i were to place a positive test charge then it would go from top to bottom if there was a positive charge in the center it was avoiding and a positively charged particle at the top, but an electron at the bottom so it would avoid...

Hello everybody! Let's begin with the spin. Spin of the ##\Lambda## is ##1/2## and of the pion is ##0##: $$ \frac{1}{2} \otimes 0 = \frac{1}{2}$$ Since I know from the homework statement that ##L=1##: $$ \textbf{J} = \textbf{spin} \otimes \textbf{L} = \frac{1}{2} \otimes 1 = \frac{1}{2} \oplus...

OK, I understand that a gamma ray is just an electromagnetic wave, and so a gamma particle could be a photon, but somehow I think that the author here is not being that sophisticated: https://www.theatlantic.com/magazine/archive/2019/09/why-are-washing-machines-learning-to-play-the-harp/594706

The wave function described seems impossible. Wave functions have to be differentiable at all points, right? Otherwise they don't represent a physically realizable state. The wave function in the example isn't differentiable at x=A, the maximum point. Also, for problem (c), I know it's visually...

This is a bit of a vague question, but I was wondering if someone could explain. As far as I know, potential energy is formally a property of a system (for instance, the GPE of two gravitationally attracting particles). In many physics problems it happens to be the case that one of the bodies...

Summary: Considering a charged particle moving through a magnetic field, what forces does the particle exert on the magnet that is causing it to deflect? Hi all, probably a dumb question, but what force(s) does a charged particle exert on a magnet as it passes through it's magnetic field and...

Homework Statement: Consider electron precipitating vertically into an auroral arc of area 1.0 km x 1200 km in the horizontal plane. The energy of the electrons is equal to 5 keV and the electron flux is 8.0 x 10^13 m^-2 s^-1. Determine the total particle energy into the arc, the total current...

It's been a long time since my last exam on QM, so now I'm struggling with some basic concept that clearly I didn't understand very well. 1) The Sch. Eq for a free particle is ##-\frac {\hbar}{2m} \frac {\partial ^2 \psi}{\partial x^2} = E \psi## and the solutions are plane waves of the form...

I am currently studying the Massive Thirring Model (MTM) with the Lagrangian $$ \mathcal{L} = \imath {\bar{\Psi}} (\gamma^\mu {\partial}_\mu - m_0 )\Psi - \frac{1}{2}g: \left( \bar{\Psi} \gamma_\mu \Psi \right)\left( \bar{\Psi} \gamma^\mu \Psi \right): . $$ and Hamiltonian $$ \int \mathrm{d}x...

Electrons passing through a double slit is in a superposition of passing through the left slit and the right slit, thereby producing an interference pattern on the screen. But when a detector is placed to detect which slit the electrons pass through, the interference pattern is destroyed. How...

What are the most likely modes of decay for ##\Omega ^{-}## into 2 hadrons? ##BR_{k}=\frac{\Gamma _{k}}{\Gamma}## ##\Gamma=\frac{\hbar}{\tau }## ##\Gamma _{k}=\Gamma _{if}=2\pi \rho|<\Psi _{i}|H_{Int}|\Psi _{f}>|^{2} (E_{f})## I took a look at the Particle Data Group, and the most likely modes...

My first idea was to find an expression of the muon momentum as a function of the angle and then maximaze the expression. But my attempts were not succesful. I report here my attempt. Set up (referring to the attached file "bettini.pdf"): $$ p = (\sqrt{p_k^2+m_k^2},0,0,p_k)$$ $$ k_1 =...

A particle was resting on top of a dome and given a negligible push such that it falls. The question is at what angle will the particle fall off the dome. The solution is that, m\frac{v^2}{a} = mg\cos\theta - R and by conservation of energy 0 + mga = \frac{1}{2}mv^2 + mga\cos\theta then the...

Jan Sperling et al., Wave-particle duality revisited: Neither wave nor particle, arXiv:1907.09836 From the abstract:

Hi, please could I ask for help with the following question: A smooth hollow circular cone of semi-angle α, is fixed with its axis vertical and its vertex A downwards. A particle P, of mass m, moving with constant speed V, decribes a horizontal circle on the inner surface of the cone in a plane...

First of, I have no idea what I'm supposed to do with the neutrinos and the photons. Can somebody explain how to handle these? The rest of what I tried is quite straight forward $$\begin{align*}\Delta E &= 4M_p - M_{He} - 2 M_e + E_{\text{Neutrino and Photons}}\\&= 4M_p - (2[M_p+M_n]-E_B) - 2...

Attempted rewriting acceleration, a, in terms of dv/dt and then separating variables to integrate. This didn’t work... So then I remembered that my gamma factor is also a function of v (!), but then I think I would be required to play around with integration by parts, which seems overly...

I've wondered what would happen to a particle if it could break through the 186,000 miles/second speed barrier and go faster than light. Would it go say 186,001 miles/second or would it go infinitely fast. I know Einsteins Special Relativity prohibits this but I have just wondered. Now if this...

Time travel, or more precisely time dilation, has been a well known proven result of Relativity. It has been demonstrated most notably in satellites traveling thousands of mph around the world with GPS. You can only go forward with our current understanding of physics. Have there been any...

I know there are numerous threads on this and I have read quite a bit such as EPR and Bell's inequality. I hope I can ask this the right way: A particle has 0 spin and gives off two children particles with spins -1/2 and +1/2 (we don't know which is which yet, or they have to end up this way...

I went with R=mv/qb, thus -> 6.64e-27*35.6e3/2*1.6e-19*1.8, and got 4.1e-4 m (metres), so diameter is 2R, 8.2e-4 m, as an answer, the reference site gives 3.95e+10 m as the answer, who's right here?

I have to find pμ(τ) of a particle of mass m and charge q with v(0) = (vx(0), vy(0), vz(0)) in a electric field E parallel to the y-axis and a magnetic field B parallel to z axis, both constant and uniform, with E = B. Here follows what I have done (see pictures below): I wrote 4 differential...

If particle beam or laser beam weapon would be used to cut the electrical wires in high voltage transmission lines of the enemy. Could the current conducts into the particle beam (or laser beam) itself and can short circuit in the weapon platform? I know ionized air can conduct electricity...

If particle accelerators with circumference of the Earth could be built (imagine around the world). How many TeV can it reach? Maybe new physics can occur at 2000 TeV. I heard the US nuclear arsenals costs 2 trillion dollars. Worldwide, the total costs of all nations nuclear arsenals may reach...

The integral has the form: $$\frac{s^2\nu^4}{(2\pi)^2}\int_{-1}^1 u(1-u^2)k_f^5[|r_1\chi_1|^2+|r_1\chi_2|^2-|r_1|^2\chi_1^*\chi_2\cos(2k_f\sqrt{u^2-\nu^2}a)-|r_1|^2\chi_2^*\chi_1cos(2k_f\sqrt{u^2-\nu^2}a)]\, du$$ ##r_1,\chi_1## and ##\chi_2## are also imaginary functions of u, because the form...