Particle Definition and 1000 Threads

I am on my first year of my master's degree in nuclear and particle physics, and right now i am ending my first semester, where i decided to take a course in physics of semiconductors. As i end this semester i start to wonder if there was any use in learning about this subject, as it seems like...

Hi, I am trying to determine the velocity of the particle with the mass m coming out of the acclerator. I tried writing : Ep(i) + Ec(i) = Ep(f) + Ec(f) Ec(f) = Ec(i) - Ec(f) But at this step, I'm no longer sure how to express Ep with V because : In my textbook, it's written : Ep = 0,5...

I don't understand why my solution is wrong. Here is my solution. $$ r_{\theta} = R\cos{\theta} \vec{i} + R\sin{\theta} \vec{j} $$ $$ v_{\theta} = v\cos(\theta + \frac{\pi}{2}) \vec{i} + v\sin(\theta + \frac{\pi}{2}) \vec{j} $$ $$ p_{\theta} = mvR(-\sin{\theta}) \vec{i} +mvR(\cos{\theta}...

This seems important to me, since in some interactions, particles are produced by pairs of opposite momentum in the rest frame of the interaction.

Hello! If I have a single ion traveling at a given energy (on the order of 10 keV), is there a way to read out its energy in real time with a single pass? Basically I was wondering if there is a device able to measure the current or magnetic field induced by the ion passing through it (while...

Summary:: I'm trying to understand the meaning behind the answer of 2.34... but I haven't taken a quantum class yet so I'm utterly lost. So I took this physics class that's teaching us python and for our final project our teacher assigned random problems to work out, well I got stuck with a...

Hi all, I'm opening this thread because of my uncertainty in how to correctly approach this exercise. My first thought was that, since the plate is subject to friction with the floor, it is going to stop, thus the final moment is 0. Hence, from the conservation of linear moment: $$m_Av_A+\sum...

Hello! I have a particle in a Penning trap (moving only along the axial direction) and I have a resonant circuit connected to one of the electrodes, measuring the current induced by the particle. Assume that the energy of the particle is much bigger than the thermal energy of the circuit (##k_B...

"Everything is a particle whose position is predicted by a mathematical wave. Light is not a wave but is packet of energy whose position is predicted by the wave.The same goes for an electron. Interference pattern is a probability distribution of where we are likely to find an electron. When...

I'm having trouble putting the rest of the equations together, I believe I need the different from (0,0,0) to (1,0,0) and then (1,0,0) to (1,1,0) right? Then solve for x direction and y direction. What would I use for Wnc tho? I'm very confused.

I have attempted but I don’t get anywhere.

The final wave function solutions for a particle trapped in an infinite square well is written as: $$\Psi(x,t) = \Sigma_{n=1}^{\infty} C_n\sqrt{\frac{2}{L_x}}sin(\frac{n\pi}{L_x}x)e^{-\frac{in^2{\pi}^2\hbar t}{2m{L_x}^2}}$$ The square of the coefficient ##C_n## i.e. ##{|C_n|}^2## is...

Hi I'm new to quantum mechanics, Looking for some help regarding a concept i am struggling to solve. I am curious if I had a cube of particles in a ground state and another cube with the same particle in a higher energy state. If I placed one upon another, is there anything in quantum mechanics...

If I have a particle with a average lifetime of 15min, if I take 10 particles confined in a box, after 15 min there will be 5 particles. After 15min 2.5 particles and so on... , but so, at the end there will be the last particle that decades. That particle lived far longer than 15min, but is the...

If a charged particle moves through a potential difference, it gains kinetic energy but does it also lose potential energy? When I accelerate a particle and then I "free it", what happen to its potential energy if the total energy should be conserved?

-1st: Could someone give me some insight on what a ket-state refers to when dealing with a field? To my understand it tells us the probability amplitude of having each excitation at any spacetime point, but I don't know if this is accurate. Also, we solve the free field equation not for this...

I hope the following questions relating to heading of this thread belongs to this forum.

This is jut an example to illustrate my doubt. I don't know how to obtain the tracjectory given only the acceleration in this format. I realized that if i can show that there is an constat vector 'a' that satisfy a•r=constant, than the motion would be on the surface of a cone. So i tried to make...

Show that a point with acceleration given by: a=c*((dr/dt)×r)/|r|3 where c is a constant, moves on the surface of a cone. This is jut an example to illustrate my doubt. I don't know how to obtain the tracjectory given only the acceleration in this format. I realized that if i can show that...

Hi :) This is a problem from David Tong's Classical Dynamics course, found here: http://www.damtp.cam.ac.uk/user/tong/dynamics.html. In particular it is problem 6ii in the first problem sheet. Firstly we can see the lagrangian is ##L = \frac{1}{2}m(\dot{r}^2+r^2\dot{\theta}^2+\dot{z}^2) -...

If ##\hat{T} = -\frac{\hbar}{2m}\frac{\mathrm{d^2} }{\mathrm{d} x^2}##, then the expectation value of the kinetic energy should be given as: $$\begin{align*} \left \langle T \right \rangle &= \int_{0}^{L} \sqrt{\frac{2}{L}} \sin{\left(\frac{\pi x}{L}\right)}...

I tried solving the problem using the force formula, so what I have known is the magnetic field B and E. I also have a motion in the x-axis, that means that the velocity will be pointed at the x-axis. Inserting this in the formula I will be having something like this: $$\mathbf{F} = q(\mathbf{E}...

Consider that the particle is moving in circular with tangential velocity v, and (0,0)is its origin. I wonder why dr/dt is equal to tangential velocity instead of radial velocity (since dr/dt means how much change in radial distance in a really short duration of time)

I am doing a learning project by writing a simulation that includes capacitance and current flow amongst capacitors that may potentially be in parallel. I don't care about certain details yet - dissipation factor, frequency dependent effects, temperature. Tiny capacitences within diode junctions...

I have been reading about ontologies in quantum physics recently and I came across Bohmian mechanics. If I understood it correctly BM endorses Particle ontology. Particle ontology claims that point-like particles that move continuously in time are the fundamental building blocks. I know some...

So I think I have the principles mixed up here because I'm getting kind of "circular" answers. ## N = N_1 + N_2## ##dN## = 0 bc/ particle number fixed so ##dN_1 = -dN_2## ##F = cN^2 = c(N_1 + N_2)^2## In diffusive equilibrium, free energy would be minimized and chemical potentials equal... $$...

I am starting my Master's Degree in Nuclear and Particle Physics, should i invest in taking a course in Parallel Computation? I know the role that Parallel Computation has in particle physics, but is there any use in a particle physicst learning about parallel computation, or could it be...

Hi, my son is fan of the Quantum Physics and we developed a cloud chamber. I'm attaching an image of particle sequence and I will like to find some help to know witch particle is. I will appreciate any help on it. Thanks

How does the photoelectric effect prove the wave-particle wrong? Higher intensity does not mean higher energy. If we were to assume the wave-particle model, an increase in intensity means an increase in the amplitude of the wave right? The energy of light is never dependent on amplitude, it is...

I have attempted a solution using conservation of momentum. Could people help check if this solution is correct (the result looks weird), as the problem doesn't have solution with it. $$ \begin{aligned} \begin{pmatrix}Mc \\ 0\end{pmatrix} &= \begin{pmatrix}E_R/c \\ \mathbf{p}_R\end{pmatrix} +...

General relativity tells us that an object in free-fall is actually inertial, following a geodesic through curved spacetime, and not accelerating. Instead, it's objects like us, on the surface of a large body, that are accelerating upwards. Maxwell's equations also tell us that accelerated...

I imagine a particle traveling across 1 wave cycle. The total vertical distance traveled across the wave cycle is 4 x the amplitude of the wave. The total vertical distance traveled in 1 minute: 5 cycles in 1 second, thus 5x60 cycles in a minute then 4 x amplitudes effectively traveled per...

I would like to estimate the maximum acceleration (or deceleration) of an alpha particle that is backscattered by a heavy atom, like in Rutherford backscattering. I am interested in the order of magnitude, not in a precise value. I am assuming the collision is elastic. The kinetic energy of the...

I was reading this article at Wikipedia that says particle physics predicts that the cosmological constant is 10^120 larger than per observation: https://en.wikipedia.org/wiki/Anthropic_principle

I came across this 'problem' when I was trying to think about how a torsion spring would apply torque in something like a miniature catapult. I understand that in the context of something like turning a wrench, we can find the net torque on the wrench by treating the hand applying the force as...

Hello, I have a particle at point A with charge ##q_A##, and an unmovable sphere of radius ##R_B## at point B with a volumic charge density ##\rho##. The distance from particle A to the centre of the sphere in B is ##r##. Both objects have opposed charges, so, the particle in A, initially at...

Since it asks for the time evolution of the wavefunction in the momentum space, I write : ##\tilde{\Psi}(k,t) = < p|U(t,t_{0})|\Psi> = < U^\dagger(t,t_{0})p|\Psi>## Since ##U(t,t_{0})^\dagger = e^{\frac{i}{\hbar}\frac{\hat{p^2}t}{2m}}##, the above equation becomes ##\tilde{\Psi}(k,t) =...

For a massless particle let\begin{align*} S[x,e] = \dfrac{1}{2} \int d\lambda e^{-1} \dot{x}^{\mu} \dot{x}^{\nu} g_{\mu \nu}(x) \end{align*}Let ##\xi## be a conformal Killing vector of ##ds^2##, then under a transformation ##x^{\mu} \rightarrow x^{\mu} + \alpha \xi^{\mu}## and ##e \rightarrow e...

I am interested on how Feynman diagram is formed from a differential equation model of particle interaction wherein the incoming particles are not bound (e.g., separated neutron, proton and electron) and one or more of the outgoing particles are bound (e.g., hydrogen atom). However, I had never...

Knowing that ##F(x)=-\mathrm{d}V(x)/\mathrm{d}x##, I found that ##F(x)=-2.4x^3+1.35x^2+8x-3##. But it was the only thing I could find. How can I analyze what will be the type of movement with the information presented by the question statement?

According to Wikipedia, The particle horizon is the maximum distance from which light from particles could have traveled to the observer in the age of the universe. It represents the boundary between the observable and the unobservable regions of the universe, so its distance at the present...

Which experimental physics branch has better job prospects (both inside and outside academia) - particle physics or nuclear physics? Is the difference very big?

Say we just created a particle (high probability of one-particle state), is the probability of a very far away detector getting triggered at the time of creation (probability of finding a particle outside of its light cone) zero according to QFT? Since we can detect particles and make...

I was wondering if the resulting daughter element is ionized after the parent undergoes beta(or any other kind) of radioactive decay,

The question is below. I tried reasoning that because x is constant, E is also constant however that gives me values in the range of 10^51. Then I tried to use numpy's ivp_solve function to solve the differential equation however I wasn't able to get that working either. Apparently I'm meant to...

At t= 0, we can see that the particle P has a radial acceleration of ##-2\hat j## and a tangential acceleration of ##2 \hat i##. The radial acceleration will tend to move it in a circle of a certain radius, whereas the tangential acceleration will tend to displace it parallel to x- axis...

I find a exercise in Leonard Susskind's book Classical Mechanics the Hamiltonian of a charged particle in a magnetic field(ignore the electric field) is $$H=\sum_{i} \left\{ \frac{1}{2m} \left[ p_{i}-\frac{e}{c}A_{i}(x) \right]\left[ p_{i}-\frac{e}{c}A_{i}(x) \right]...