Scattering is a general term for several physical processes in which radiation of some sort changes direction due to an interaction with a particle. Scattering can be classified by the type of radiation (ie, electromagnetic, x-ray, neutron), or by the relative sizes of the wave and the particle (ie, ...

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How to calculate the differential scattering cross section?

I am doing some simulations with the Meep code to study some properties of a metal nanoparticle. The situation is this: an incident electromagnetic wave on a metal nanoparticle. By now I know how to ...
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18 views

Mode-dependent Andreev reflection

Consider the following Hamiltonian which describes massless Dirac fermion on the surface of a topological insulator nanowire, $$H = -i\hbar v_{F}\left[ \partial_{x}\sigma_{x} + ...
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32 views

Increase contrast on the image taken by CCD camera

I project a pattern on a reflecting object and I capture the reflected pattern (reflected via the object) using a CCD camera. However, the reflected pattern has a very low contrast (due to volume ...
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29 views

How to determine the sign of the s-wave scattering length?

I guess it is relatively easy to determine the magnitude of the scattering length $a$. We just need to measure the scattering cross section. In this way, we can determine the value of $a^2$. But ...
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22 views

Spin dependent Andreev refelction

What happens with the spin in Andreev reflection process ? The simple Bogoliubov - De Gennes equation for hole and electron does not contain information about the spin. I know there are some ...
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42 views

What excactly is a “fourier component of a density fluctuation”?

Light scattering texts say depending on the scattering angle, you are seeing a certain fourier component of a density fluctuation. This density fluctuation varies sinusoidally due to Brownian motion ...
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scattering matrix superccurent density of states

while studying scattering formula for the supercurrent (Beenakker) I encountered that the density of states for discrete and continuous spectrum can be simultaneously described by taking $\epsilon\ ...
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98 views

In scattering, how does a particle 'know' which direction it is being illuminated from?

In scattering experiments, for example light scattering, the scattering strength from different sized particles is depicted as below. What I can't understand is: how does a particle know which ...
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24 views

What reflects/scatters sunlight most?

The difference between a white object and a mirror is mainly scattering versus reflection. If we neglect this difference and define the reflectivity by input energy minus transmitted energy minus ...
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362 views

BBC radiation: What is it?

I'm reading articles about blazars, and in a discussion about models concerning Blazar SEDs (Spectral Energy Densities) there are mentions of different processes: Sychrotron scattering, inverse ...
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55 views

What is the difference between Rayleigh scattering and Thomson scattering?

After reading the wiki articles I know, that both Rayleigh scattering and Thomson scattering are elastic processes. But what is the essential difference between those two processes, their cross ...
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33 views

Suggest me specific book for studying scattering theory and special functions [duplicate]

I am doing msc physics. And we are studying major part of scattering theory. I used Quantum Mechanics by Davydov, Griffiths, etc, to study scattering theory. But I am not understanding it properly, ...
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197 views

How to replace $T$-product with retarded commutator in LSZ formula?

I am reading Itzykson and Zuber's Quantum Field Theory book, and am unable to understand a step that is made on page 246: Here, they consider the elastic scattering of particle $A$ off particle $B$: ...
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71 views

Why is scattering vector $\vec{q}$ called vector of 'momentum transfer'?

In the world of scattering the angle at which you detect the scattered radiation is known as $q$, where $$ \vec{q} = \frac{4\pi\eta}{\lambda}\sin(\theta/2) $$ I read in a lot of books that this is ...
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76 views

Green functions in QFT

What is the sense of Green function $$ \langle | \hat {T}(u_{1}(x_{1})...u_{n}(x_{n})\hat {S})|\rangle , \quad \hat {S} = \hat{T}e^{i\int \hat {L}(x)d^{4}x} ? $$ How is it connected with scattering ...
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33 views

optical diffusion (scattering) versus refraction

When an electromagnetic wave meets an interface a part of it is reflected and part of it is refracted (and from the refractive index I can calculate the angles of propagation and the intensities using ...
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83 views

Poles for a particle scattered in a delta potential

I am working on problem a professor gave me to get an idea for the research he does, and have hit a point where I'm having a difficult time seeing where I need to go from where I'm at. I would also ...
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37 views

Forward-scattering off a potential well

In his book, James Binney writes the following: My question is what is the meaning of this expansion as $1+T$? I say this because you don't tend to consider the possible "paths" that a particle ...
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25 views

Form Factor in Rutherford Scattering

My question relates to Rutherford Scattering of particles. When we calculate the "differential cross-section" expression for a nucleus with finite size, it is said that the expression is almost the ...
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108 views

Is the total cross section a Lorentz Invariant?

In Peskin and Schroeder's book (P&S), on the botton of page 106, the authors say that the total cross section transforms as its only non-invariant factor, namely: $$ {1 \over E_{A} E_{B} |v_A - ...
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37 views

How to prove that identical particles are attracted or repelled in a given spin-s interaction theory?

Let's assume that we have integer spin interaction theory (EM field, linearized gravity, arbitrary gauge spin s theory). How to prove the consequence that in interaction theory with spin $s = 2n$ two ...
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34 views

diffraction from sphere solution

I want to solve a problem of plane wave diffraction by a large sphere. There is a formula that I found from papers, but I think needs numerical solution. please help me to solve it The formula is ...
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25 views

Why is number of collisions equal to number of scattered particles times number of scatterers?

In Landau, Lifshitz "The Classical Theory of Fields" $\S12$ "Invariant cross-section" the following is said1: ... according to the usual definition of the cross-section $\sigma$, the number of ...
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52 views

What limits of integration do Landau and Lifshitz use here?

In "Mechanics" book by Landau and Lifshitz, $\S18$ "Scattering", problem 7 on deducing the form of scattering field given the effective cross-section as a function of scattering angle an equation is ...
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27 views

scattering of light

How does the path of light become visible due to scaterring of light? According to me it will only tell the presence of colloidal particle but the book give the example of cinema hall projector and ...
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131 views

Calculating probability current for scattering problem

I'm trying to calculate the probability current for a scattering problem. The potential is $V = V_0 > 0$ in $x>0$, with $E>V_0$ So I have in the region $x \le 0$: $$\psi = \exp(ikx) + R ...
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81 views

How can opaque black object occur?

I know the fact that a material appeared as black when all wavelength photons were absorbed. I also know that opaque object is the result of reflection and scattering of light wave. Is it right? ...
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96 views

quantum theory of light

What's the scattering matrix for a PBS (polarization beam splitter) ? Is it just unitary ? If one polarization never couples into another polarization (then there's a lot of zeroes in that 4x4 matrix) ...
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60 views

Coherent Intermediate Scattering Function from Simulations

I want to calculate the coherent intermediate scattering function, $S_{\text{coh}} (\mathbf{Q},t)$, from a molecular dynamics trajectory, based on its definition. The definition of the function is: ...
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55 views

How to specify BRDF measurement

As a person who will be using the scattering measurement results (in Zemax), I was asked to prepare the specs for the BRDF measurement. However I've never done it until now, so help would be greatly ...
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59 views

How to determine the trasmission coefficient of a gaussian wave packet scattering on an finite square well?

I am doing a scattering simulation of a gaussian wave packet on a finite square well. I have solved numerically the Schroedinger equation and I know the values of the wave function after the ...
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24 views

Scattering of two particles - phase factor

I did see some posts on stackexchange on this matter, but I find them to be beyond my scope or not directly related to what I am looking for. I am reading Feynman Lectures III, chapter 4. It talks ...
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21 views

Lippmann-Schwinger equation and x-ray scattering

The Lippmann-Schwinger equation in the first Born approximation, in the far field, is the Fourier transform of the potential. The scattering potential for an electron beam incident on a crystal is by ...
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127 views

Numerical solving of 2D and 3D Schrodinger equations

I am studying 2D quantum scattering models for my Bachelor's thesis. Somewhat like these: ,with Dirichlet ($\psi \mid_\Gamma = 0$) boundary conditions on the "walls" of the waveguide and the ...
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96 views

Polarization vectors in scattering amplitudes

The annihilation ($e^+ e^-\rightarrow 2\gamma$) diagrams are I'm just wondering if the amplitudes should be $$(-ie)^2\left[\bar v(p_2)\gamma^b\epsilon_b^*\frac{-i(-(\gamma^\mu p_{1\mu}-\gamma^\nu ...
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Optical Theorem ,how can experiment distinguish the unscattered wave from the forward scattered wave?

How can experiment distinguish the unscattered wave from the forward scattered wave? The Optical Theorem says the imaginary part of the forward wave determines the cross section for an initial ...
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Why can't we see gases?

I am not sure what causes gas molecules to be invisible.This question may look silly but I really want to know the story behind it.
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70 views

Question about the Klein Paradox

I am trying to understand some points about the paradox, what I am doing is solving the for the step potential $$ V = V_0 ~\theta(z) $$ I have two solutions $$ \Phi_I = e^{ik_1 z} + r e^{-ik_1 z}$$ ...
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188 views

Compton Scattering: Klein-Nishina formula derivation

I'm following a derivation of the Klein-Nishina formula from scratch and this is what I have so far: $P_{e,i} = m_0\gamma_u[1,u]$ and $P_{\gamma,i} = [\frac{\hbar\omega_i}{c^2}, ...
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45 views

regarding the infinite cross section in Rutherford scattering

The differential cross section of Rutherford scattering blows as $\theta\rightarrow 0$. People express this fact as "The Coulombic potential is of long range". But I am seeing the opposite: $\theta ...
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144 views

Eikonal approximation in QFT

Does the eikonal approximation for calculating a scattering amplitude in QFT provide the exact result in the limit of $s\rightarrow\infty$ at finite $t=0$ ($s$ and $t$ are the usual Mandelstam ...
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2answers
100 views

Lippman-Schwinger Equation with Outgoing Solutions

I'm reading about Green's functions and how the Lippmann-Schwinger equation eventually leads to the textbook expression for the form of scattered wavefunctions by a central potential in the far ...
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1answer
119 views

A question about the energy of turning on and off interaction adiabatically in QFT

I read a saying as follows: In a theory with no particles which decay and no bound states, the turning on and off of the interactions merely serves to limit the effective range of forces. In this ...
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2answers
57 views

How does a wave packet acts rigidly?

Particles can be represented as wave packet. So how do particles get scattered? Waves superimpose on one another, they don't bounce off of on one another.
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1answer
100 views

Why are neutrino and antineutrino cross sections different?

Particularly in the case of Majorana neutrinos, it seems a little odd that the particle and antiparticle would have differing cross sections. Perhaps the answer is in here, but I've missed it: ...
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Conflict between Lippmann–Schwinger equation and Gell-Mann and Low theorem about energy

Lippmann–Schwinger equation states that scattering state will have the same energy as free state, while Gell-Mann Low theorem says that they have different enery. Lippmann–Schwinger equation says: ...
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28 views

How do I determine resistivity from electron defects of high purity gold?

I am trying to create a plot for the electrical resistivity of high purity gold from 1 K to 1000 K. I found gold's resistivity at 300 K using the Wiedemann-Franz Law based on thermal conductivity data ...
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46 views

String Vertex Operators in Light Cone Gauge

I have a basic confusion about how to compute string scattering amplitudes in light cone gauge, using the operator formalism reviewed in GSW. I am familiar with the covariant gauge formalism, where I ...
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69 views

$\mathrm{d} \Omega_{CM}$ for a $1\rightarrow 2$ particle decay?

The differential solid angle is described in e.g. Srednicki's QFT text but only for the case of scattering. Because in the case of scattering it's defined with respect to the incoming three-momentum ...
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Allowed interactions in bosonic string theory

In a quantum field theory, only a finite set of interactions are allowed, determined by the Lagrangian of the theory which specifies the interaction vertex Feynman rules. In string theory, an ...