Particle Definition and 1000 Threads

Here we consider a black hole formed by gravitational collapse classically. We also consider a scalar massless Klein-Gordon field propagating on this background. To quantize the field we expand it in appropriate modes. The three sets of modes required are: The incoming modes, appropriate for...

My question about quantum entaglement is: is a Quantum particle's spin [altered] into another spin position at the moment of detection or is it just a 'snapshot picture' of the spin at the moment of detection (without alteration)? It seems this is an important differentiation. If there is no...

Hi. I have just looked at a question concerning a free particle on a circle with ψ(0) = ψ(L). The question asks to find a self-adjoint operator that commutes with H but not p. Because H commutes with p , i assumed there was no such operator. The answer given , was the parity operator. It acts...

What justifies the use of multinomial coefficient in the combinatorics used by Boltzmann? The particles are distinct but counts as identical when they are in the same energy state?

The Standard Model Lagrangian contains terms like these: ##-\partial_\mu \phi^+ \partial_\mu\phi^-## ##-\frac{1}{2}\partial_\nu Z^0_\mu\partial_\nu Z^0_\mu## ##-igc_w\partial_\nu Z^0(W^+_\mu W^-_\nu-W^+_\nu W^-_\mu)## How should one interpret the "derivative particle fields" like...

I've been working on modifying the cyclotron particle accelerator. Tell me what you think? It's pretty basic though

A uniform beam of positively charged particles is moving with a constant velocity parallel to another beam of negatively charged particles moving with the same velocity but in opposite direction separated by a distance d. Then, how should be the variation of magnetic field B along a...

Statement of the problem : "Using the definition L = r ##\times## p, prove that the direction of L is constant for an alpha (##\alpha##) particle whose scattering is shown in the diagram below. " Relevant equations : We are aware that the scattering takes place via a central force F = F(r)...

In an inertial frame, consider that a particle's position and the time measured by a clock in this frame are respectively, ##(t,x)##. Suppose there's another frame, moving with constant speed ##v_R## with respect to the frame described above. The particle acceleration is given in the first...

Hi everyone. I want to make a very small accelerometer. (A micro or nanosized MEMS accelerometer) What do you think about this idea? I will have a source which will emit alpha particles. I will place two movable magnets at both sides of the alpha particle. When I apply acceleration to the...

Is it possible to change a fundamental property of a particle? If that can be done, will it's twin particle's state also be altered accordingly?

Hi. I'd like to ask what are the differences between Particle Physics, Quantum Field Theory and the Standard Model. I see these names of physics courses but I want to confirm if I understand the difference. My understanding is that when students learn particle physics in their undergraduate...

Homework Statement Twelve equal particles of charge ##+q## are equally spaced over a circumference (like the hours in a watch) of radius R. At the center of the circumference is a particle with charge ##+Q##. a) Describe the net force acting over ##+Q##. b) If the charge located at...

Homework Statement The acceleration of a particle given a=A√t where A=2.0 m/s5/2. At t=0, v=7.5 m/s and x=0. (a) What is the speed as a function of time? (b) What is the displacement as a function of time? (c) What are the acceleration, speed, and displacement at t=5.0s. Homework EquationsThe...

Homework Statement The position vector of a particle changes: Only by its module. Only by its direction. What can be said about the trayectory of the movement of the particle? Obtain the answer analitically. Homework Equations None. The Attempt at a Solution I think that the trayectory...

I am working on a research project where I intend to describe what the Penrose process would like in a sonic black hole. I have found what a rotating (Kerr) black hole looks like in the sonic analog: https://arxiv.org/pdf/1802.08306.pdf I have also found that the analog of massless particles...

Homework Statement CLASSICAL MECHANICS [/B]Homework Equations E=U+K[/B]The Attempt at a Solution Guys, can you please help me with part b) ? I am not sure how to find the velocity. Thanks

My question is can we have negative energy in classical mechanics? Also I would need help for finding the velocity in part b)

Homework Statement U - 238 is undergoing alpha emission into Th - 234. U - 238 has half – life of 109 years. Calculate the emission rate of alpha when uranium has mass of 10 grams Homework Equations A = λN A = A0 (1/2)n , n = t / half - life The Attempt at a Solution Not sure how to do it but...

Homework Statement (I) An experiment to determine ceramic particle sizes showed that the rate of descent when suspended in a fluid ranged from 1.2 × 10–6 m s–1 to 5 × 10–6 m s–1. 
The density of the material was 3800 kg m–3 and the density and viscosity of the fluid at room temperature were...

Particles follows accordingly the general equation: $$ m*\overrightarrow{a}=q*\overrightarrow{E}+q*\overrightarrow{v}\wedge \overrightarrow{B} $$ But in the case of two coupled coils the time varying current at primary coil (and its magnetic field variation) creates corresponding varying...

I have been interested in particle physics since I was in High School, but I have struggled to keep my GPA high enough to get me into grad school and I want to serve my country. I decided that the military was the best route to get the experience I needed. I would like to work with lasers to...

Is anyone did experiment on diffraction with single particle at a time? Do they get diffraction pattern? I referred particle as both electron and photon And I want to know any experiment( classical, or single particle at time) don't show any diffraction pattern in single slit experiment.

A moving particle has been at position X for zero time. Was it ever at position X? Can zero time be considered as never, as in "I was in Rome for zero amount of time."? It seems like it would have been at position X if time passed in pieces the size of Plank time.

The furthest distance that we can see is defined by the Radius of the Particle Horizon which its nearly 46 Gly. However, the cosmic event horizon is nearly 16 Gly. Is this means the galaxies that further than the 16 Gly are just will stay the same in the sky? Since their light can never reach...

Yes it sounds like I've lost it but I really want to build one. I was wondering is someone could guide me to useful resources. I'm currently reading some patents I found online to gain some more insight. Any help would be appreciated. Thank you.

Homework Statement A charged particle has an electric field at ##\langle -0.13, 0.14, 0 \rangle## m is ##\langle 6.48\times10^3, -8.64\times10^3, 0 \rangle## N/C. The charged particle is -3nC. Where is the particle located? Homework Equations ##\vec E=\frac 1 {4π\varepsilon_0} \frac q {|\vec...

Hi everyone, I am working on matrix inversion and focusing on low-complexity method such as iterative method. Recently, I am interested to explore how particle swarm optimization (PSO) can be applied to do matrix inversion. Since I am very very new in PSO, I have no idea how to start my work...

Hi, I have been doing some simulation with MCNP. They take a long time. I think there is a way to ignore some particle histories, which reduces the time for simulations. In my model, there is a point neutron source, an object, and a detector. Most of the neutrons do not reach the detector. So...

The positive lambda has a quark composition udc, and a lifespan of 2 x 10 minus 13 seconds. When this particle is created in a collision, inside a modern detector, how long will its track be? At near the speed of light, its lifetime would allow it to traverse less than a tenth of a millimeter...

The action for a relativistic point particle is baffling simple, yet I don't really understand why it is written as, $$S = -m\int ds $$ I know it's right because we get the right equations of motion from it, but can one understand it in a more intuitive way?

Why for the free particle, the group velocity and phase velocity are not the same while we have only one wave? What is the envelope here?

Homework Statement Both m1 and m2 (m1=2m2) masses can slide without friction over parallel and rigid bars that are placed at a distance d from each other. A spring with elastic constant k and with zero natural length connects both masses. The system is placed on a table. The system is released...

we all know that particles do spin. But my question is why it does so why do they spin? what will happen if they stop spinning? what makes the particle to do so?

The atomic nuclei consist out electrons, protons and neutrons (with only exception of hydrogen, that does have a neutron). Thus, it would be straightforward, that there existed a corresponding radiation for each nucleus component, when a nucleus decays. There is an electron radiation (beta...

Homework Statement Question attached : Just number 1 please Homework Equations Hamiltonian is given by eq ? In the attachment ##\phi(x_1,x_2,...x_n,t)= \int dx_1...dx_n \phi(x_1,x_2...x_n,t) a^+(x_1)...a^(x_n) |0> ## Where ## |0> ## is the vacuum state and ##a(x) |0>=0## The Attempt at a...

For a wave A sin ( kx - ωt) and a wave A sin ( kx + ωt) traveling opposite to each other, on evaluating by applying superposition principle , the resultant displacement function is 2A sin ( kx ) cos (ωt) . For different Node Anti-node configurations we calculate natural frequencies of the...

Is it possible to measure an electron, and, say, get multiple simultaneous results about it's motion, as you didn't break superposition? (E.g. you could simultaneously read 5mph, 10 mph and 15mph), and could this be used for quantum computers, to store store and gain huge amount of information...

Homework Statement [/B]Homework Equations Doing this problem like e.g setting the determinant of potential matrix and the ω2*kinetic matrix equal to 0 ,det(V-ω2T)=0,I got the frequency of the normal modes of vibration to be 2ω0 and ω0 where ω0 is the natural frequency, But sir how to treat...

Homework Statement Homework Equations Doing this problem like e.g setting the determinant of potential matrix and the ω2*kinetic matrix equal to 0 ,det(V-ω2T)=0,I got the frequency of the normal modes of vibration to be 2ω0 and ω0 where ω0 is the natural frequency, But sir how to treat this...

Ugh ... I remember there was a reason ... but forgot what it was. So here's 3 bits of information gathered from dozens of sources, textbooks, official sites: Alpha particles are identical to Helium nuclei. Alpha particle mass = 4.001506 u helium-4 nuclei mass = 4.0026032 u OK, so ... why...

Homework Statement A particle moves along a parabola on the x-y plane with equation ##y^{2}=2px## with constant speed ##1000m/s##.What is the magnitude of its acceleration? Homework Equations Parametric equations ##\vec{r}=(b^{2}t^{2}/(2p),bt)##. The Attempt at a Solution...

I'm trying to understand the following derivation. Starting with the one-dimensional equation for a traveling wave ##u = u_0 \exp{[j(\omega t - \beta z)]}## the goal is to derive the phase relation between strain and velocity. The author first derives the relationship between strain and particle...

If you have a particle in a 1-d box with a finite potential when ##0 < x < L ## and an infinite potential outside this region, then the normalised wavefunction used to describe said particle is ## \psi (x) = \sqrt{\frac{2}{L}}\sin(\frac{n\pi x}{L})##. However, if you had say instead a finite...

Hello everyone. I am triyng to calculate the route which takes less time to go from point A to point B in the presence of a constant flow (I. E. a simple version of Zermelo's navigation problem) using the GAMS software. However, if I put both points on a straight line and make the constant flow...

Homework Statement A point particle travels in a straight line at constant speed, and the closest distance it comes to the origin of coordinates is a distance l. With respect to this origin, does the particle have nonzero angular momentum? As the particle moves along its straight-line path...

So, I've been really interested in Particle Physics since 6th grade when I did a project on particle accelerators. I understand most of it, except for one thing, the radio frequency cavities which are used for acceleration. I just want to ask, how do the Superconducting Radio Frequency Cavities...

My question is - is all light a wave until observed, then wave function collapses and behaves as a particle? This is far fetched (and i don't subscribe to it!), but theoretically could light from a distant object passing through a double slit experiment and exhibiting a particle pattern be...

Hi, I was wondering if there are any proposed ideas for the mystery particle at 28 GeV? Please see article http://theconversation.com/mystery-particle-spotted-discovery-would-require-physics-so-weird-that-nobody-has-even-thought-of-it-106260

would it be a more economical idea to accelerate cosmic rays from the atmosphere which are already traveling at 43 percent of speed of light as particles in a particle accelerator. Do you think that this would be more economical in principle or that you could achieve higher collision speeds?