Particle Definition and 1000 Threads

Early in Bellan he asks us to consider a finite-temperature plasma and assume that the ion and electron densities are initially equal and spatially uniform. He approaches the problem of calculating the Debye length by considering each species of particle, σ , as being a fluid so that the...

Let's say that I observed a free particle at a certain location. Is there any way I can calculate the probability of finding that same particle at another location when I look for it again?

I have a question about this picture: It shows matter traveling at relativistic velocities away from a black hole: "Figure 5.21: This VLA image of the radio-loud quasar 3C 175 shows the core, an apparently one-sided jet, and two radio lobes with hot spots of comparable flux densities. The jet...

Hi. Are these two books complementary, or do they have too much in common? https://www.amazon.com/dp/1107034264/?tag=pfamazon01-20 www.amazon.com/Quantum-Field-Theory-Standard-Model/dp/1107034736/ My problem is that I still don't quite understand the difference between university courses in...

I am a teacher and the problem statement is part of our curriculum. I feel like I have a basic understanding of what particle accelerators are, but I only have a vague idea of what the strong nuclear force has to do with this. Here's what I know: In a particle accelerator, you might smash...

If I'm trying to solve the problem of a particle in free space (H = P2/2m ). the eigenfunctions of the Hamiltonian cannot be normalized. now assume I have a legitimate wave function expressed in terms of the eigenfunction of H and I want to measure its energy. what will happen to the...

All i could think is that the z component of velocity will remain unchnged as there is no force in that direction.And for the x and y component can we imagine the helical motion as a superposition of a circle and a straight line.So for x and y component can we solve for a particle moving in a...

A particle, P, starts from rest at a point X and moves in a straight line with an acceleration expressed as a=4t. After 2 seconds, the particle reaches Y and it stops accelerating. The particle leaves Y with a velocity -3ms-1, and finally comes to rest at Z. (i) Find the value of t when the...

Attempt at solution: By conservation of momentum: $$P = (M,0,0,0) = p_1 + p_2 = (E_1 + E_2, 0, 0,0)$$ thus $$ M = E_1 + E_2 = 2k^2 + m_1^2 + m_2^2$$ Now $$E_1^2 - E_2^2 = m_1^2 - m_2^2 = (m_1 + m_2)(m_1-m_2)$$ $$ = M(m_1-m_2) = (2k^2+m_1^2+m_2^2)(m_1-m_2)$$ Isolating k: $$ k =...

I have a bit of confusion regarding the application of the uncertainty principle in the context of experiments. If a detector allows you to measure a particle's path through said detector, does that mean that you know a particle's position at all points in time, and are able to work out its...

The multiplicity of states for a particle in a box is proportional to the product of the volume of the box and the surface area of momentum space. $$ \Omega = V_{volume}V_{momentum}$$ The surface area in momentum space is given by the equation: $$p^{2}_{x}+ {p}^{2}_{y}+{p}^{2}_{z} =...

The energy-momentum tensor of a free particle with mass ##m## moving along its worldline ##x^\mu (\tau )## is \begin{equation} T^{\mu\nu}(y^\sigma)=m\int d \tau \frac{\delta^{(4) }(y^\sigma-x^\sigma(\tau ))}{\sqrt{-g}}\frac{dx^\mu}{d\tau}\frac{dx^\nu}{d\tau}. \end{equation} Let contract...

The energy-momentum tensor of a free particle with mass ##m## moving along its worldline ##x^\mu (\tau )## is \begin{equation} T^{\mu\nu}(y^\sigma)=m\int d \tau \frac{\delta^{(4) }(y^\sigma-x^\sigma(\tau ))}{\sqrt{-g}}\frac{dx^\mu}{d\tau}\frac{dx^\nu}{d\tau}.\tag{2} \end{equation} The covariant...

In Landau mechanics it's been given that multiple Lagrangians can be defined for a system which differ by a total derivative of a function. This statement is further used for the following discussion. I understand that the term for L has been expanded as a Taylor series but I can't understand...

Elementary particle can be consider as a "wave packet" of the field,but a "packet" of field must have a size.Why do we know elementary particle is point particle?

Summary: Mechanics problem related with Calculus (differential equations) Hi everyone, I would like some help in that task, if anyone would be willing to help :) Namely I have a problem from particle dynamics. "D:" means given info... so, D: m,g,h,b, miu. We're looking for v0 and S as given...

I created this in java just a while ago.

Summary: Thanks to CERN, we now have huge particle accelerators such as the LHC. We use them to enhance our understanding of quantum physics. As everyone know,particle accelerators are huge machines that smashes atoms into pieces at near the speed of light. I have heard making antimatter by...

In many physics fields, the neutron is considered as a separate particle? But the neutron decays into a proton and an electron. Why is it considered an independent particle? Although the fact of decay suggests that the neutron is a composite particle.

v = sqrt( (2 * charge of proton * 3000/e) / (mass of proton)) v = 1.893986024 x 10^`15 r = ( (mass of proton) * (velocity) ) / ((magnetic field) * (charge of proton)) r = 24715769.68 m Anyone please help

m = 0.005 q = -70 x 10^-6 c v = 30,000 m/s Since there is no movement vertically Fb = Mg So, q . V . B = mg So, (70 x `10^-6) . (30,000) . B = (0.005) . (9.8) So, B = 0.0233333 or ~ 23 MT

F = ma F = (6x10^-6) * 8 F = 4.8 * 10^-5 F = QBVsin(theta) F/(BVsin(theta) = Q (4.8 x 10^-5) / (5 x 10^-3) (4000) (sin(37)) = 3.98 x 10^-6 ~ 4 uc <---- THE RIGHT ANSWER IS -4 uc

Consider a system of 2 identical electrons that are confined in a region so that there is a single wavefunction describing the whole system. In several textbooks one can read that the probability to measure the position of an electron in region near ##r_1## and the other in a region near ##r_2##...

Hi all, I am in a bit of a funny situation where I need to pick up at least a cursory knowledge of QFT and particle physics in the space of two weeks. I borrowed "QFT and the Standard Model" by Schwartz but I have no idea how I should approach it. Ideally I'd pour through every page, but I...

Suppose there exists a pair of parallel plates with a voltage between them. These plates have a certain amount of energy stored in the electric field between them (E=1/2*C*V^2). Now we fire a fast (~5,000,000 m/s) beam of protons through the plates (parallel to the electric field) such that the...

I am having difficulties understanding this concept. Particle in a box (as far as i understood) shows that the electrons or particles need a certain about of potential energy to escape the one-dimentional potential well. I think its pretty similar to the concept of the electons and ionising...

Can someone explain how can i get that answer?

Quantum fields have wave functions that determine a particle position in space. It solves non-locality, double-slit paradox, tunnel effect, etc. What if the wave function is also in time? Won't it solve the breaking of causality at quantum level? (Delayed Choice/Quantum Eraser/Time) Not much...

I first found ##v_{B}## by ##E_{p,A,B} = mgh_{1} = E_{c, B} = \frac{1}{2}mv_{B}^2 \therefore v_{B} = \sqrt{2gh_{1}} ## After this I made several failed attempts basically trying to find its final velocity so I could use conservation of energy. Spliting the velocity into its components never...

Could a particle be sent back in time on it's world line? Time is defined by events, but at absolute zero, there is no movement or vibration of a particle - does not time cease to pass then at absolute zero for the particle? If the particle was somehow brought below absolute zero, could it be...

Hi. I will be glad if you can help me with a small problem. I got a cylinder with a density $$ \rho (r) = b \cdot e^{\lambda r} $$, with radius $$ R $$. If I let go a charge q < 0 from $$ R_0 $$ when $$ R_0 > R $$ , what will be the velocity that the charge will hit the axis of the cylinder.So...

I am trying to understand ergodic theory, i.e. how simple systems reach equilibrium. I consider a classical particle in a 2D (or 3D) box. Funnily, I have never seen this example in books (probably due to lack of knowledge). Instead, in QM, the particle in a box is a prototypical example. My...

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...

Is it possible to infer particle properties from 2 sources diffraction with no slit/slits involved? Some explanations of experiments i can find, if i understand them correctly at all, relate to the possibility of concluding particle momentum, from absorption lines, when emanating from a single...

I was recently seeing videos on standard model of particle physics and something occurred to me that ,Higgs field gives mass to elementary particles ,this gives reason for one property of matter that is mass. Why not a field that gives elementary particles a charge ? After all their are two...

Some sources say wave particle duality is very much a principal, others say it's oversimplified and not exactly true but still okay to use in order to explain things, and many say it's flat out wrong... so who's right? Can I say "wave particle duality" when talking quantum mechanics or no?

That said, my approach was to determine the energies and 3-momenta at the center of momentum reference frame for each particle, with a fixed s, and check it corresponds to each one of the above, but I'm having some trouble proving that, for example, E_A=\frac{s+m^2_A-m^2_B}{2\sqrt{s}}. I've...

Is there any experiments that validate the results of particle in a box with infinite or finite potential. Thanks

If you change the spin of an entangled particle without knowing its original spin, what happens to the other entangled particle?

I don't get why ##F \cdot dr = \frac{mv^2}{2}## I know this has to be really easy but don't see it. Thanks.

Homework Statement From Griffiths GM 3rd p.266 Consider a free particle of mass ##m##. Show that the position and momentum operators in the Heisenberg picture are given by$$ {\hat x}_H \left( t \right) ={\hat x}_H \left( 0 \right) + \frac { {\hat p}_H \left( 0 \right) t} m $$ $$ {\hat p}_H...

I have question, how can I solve problem of particle in rigid box when one of the wall gets completely destroyed? At time t = 0 the right wall of box gets completely destroyed, left wall is still here( ψ(0) = 0 ), also at t = 0 we know that particle is in ground state. How can I search for...

1. What should be the size of object/Particle (sphere) so that it should remain suspended (neither it should sink nor it should float)? container dimensions 30*25*25, density of fluid 0.9g/cm3 , density of particle 0.86g/cm3 , particle is coated with aluminium having density of 2.07g/cm3.(if...

Homework Statement The position function x(t) of a particle moving along an x axis is x = 6.00 - 7.00t2, with x in meters and t in seconds. Homework Equations (a)[/B] At what time and (b) where does the particle (momentarily) stop? At what (c) negative time and (d) positive time does the...

Homework Statement A particle (mass 6.7 × 10–27 kg, charge 3.2 × 10–19 μC) moves along the positive x-axis with a speed of 4.8 × 105 m/s. It enters a region of uniform electric field parallel to its motion and comes to rest after moving 2.0 m into the field. What is the magnitude of the...

Greetings, In the scenario of a particle in an infinite potential well, there are discrete energy levels, i.e.##E=\hbar ^2 n^2 \pi ^2/ (2 m L^2)## where L is the width of the potential well, and n takes on positive integers. But what will happen if I put a particle of energy ##E_i## that is not...

Hi all, I recently got accepted to do a PhD into High Energy Physics groups at Oxford, Imperial, UCL, Cambridge and Manchester. My main interest is neutrino physics, which all of these places are offering. However, I am struggling to pick between Oxford and Imperial. I have met and discussed...

Currently, I am doing a master in mathematical physics. I am interested in particles& field theory and want to apply a PhD in this field. But I am not sure whether I can... I just learned a little high energy physics from Griffth and Peskin' book on elementary particles and QFT. Recently, I...

Taken from the Wikipedia page: Is there something significant about the physics of the Planck Particle or its properties? If so, then what is the significance? If there's nothing especially significant about the Planck Particle, then you can just say "No" and I will consider the matter closed...

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...