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I'm trying to calculate the disintegration rate $\Gamma(t\rightarrow W^+b)$ from the Fermi Diagram:
I know the lagrangian for the interaction would be:
$$ -iF = \bar{u_b}\gamma^\mu P_Li\frac{g}{\sqrt2}U_{tb}\delta_{ij}u_t \epsilon^\mu $$
Hence, the $$|\bar{F}|^2 = \frac{g^2}{4}\sum \bar{u_b}\gamma^\mu P_Lu_t \bar{u... |
Is the speed of light constant relative to the observer?
Hypothetically, I am standing at the front of a train. The train is traveling 100 mph. I shine a flashlight pointing forward in the direction the train is traveling.
Is the light from the flashlight traveling at 670,616,629 mph or (670,616,629 mph) +the speed of... |
First, an introduction.
Consider the surface of the Earth (whose mass is $M$): the geometry of the spacetime nearby can be described to a first approximation by the Schwarzschild Metric.
If we wish to compute the 4-acceleration of an observer which is stationary with respect to the $(r, \theta, \varphi)$ coordinates, w... |
So I've been trying to solve the expression for the Hamiltonian using the canonical quantization of a complex scalar field and I am not sure of how the following step comes by, from
$$\mathcal{H} = \int \frac{d^3 \vec{p}}{2 E_p} \left[ 2 E_{p}^2 \left( \hat{a}^{\dagger}_{p} \hat{a}_p + \hat{b}_p \hat{b}^{\dagger}_p \r... |
I'm learning about Brownian motion. I use the approximation of overdamped motion. I read that the average acceleration is $0$ then, but I don't really understand the concept. So, what does overdamped exactly mean, especially in the context of Brownian motion, and why is the acceleration $0$? Thanks!
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Say there is a polarized sphere with polarization density $\vec{P} = \alpha \hat{r}$. How can I tell if the electric field outside of the sphere will also be radial? I see in many places that it is taken as obvious, but why is it?
*Edit: rephrase
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I apologize for my ignorance, but I lack the underlying knowledge to meaningfully research this myself.
My knowledge of both Solar Flares and EMPs comes almost exclusively from pop-sci reading. I've repeatedly heard/read that both phenomena damage electronics by generating rapidly oscillating magnetic fields causing tr... |
I have two cylindrical bar magnets, $1/4" \mathrm{(\sim 6mm)}$ in length and diameter.
Like all magnets with this geometry they attract each other both on the axial direction-north pole of one attracted to the south pole of the other and along their radial direction-south pole of one facing up, the north pole of the ot... |
In relativity, if two particles are moving together, which way is the correct way expressing their total energy:
$$ E=\sqrt {((m_1+m_2)c^2)^2+((p_1+p_2)c)^2}$$
or:
$$E=\sqrt{(m_1c^2)^2+(p_{1}c)^2}+\sqrt{(m_2c^2)^2+(p_{2}c)^2}$$
Or does it depend on frame of reference?
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I will refer to this video here at 5:20, https://youtu.be/ev9zrt__lec
(This also applies to anything at rest relative to you, but hard to word in the title)
The video says that the reason why a person traveling in a spaceship at an appreciable fraction of the speed of light does not experience effects of time dilation ... |
I'm trying to make some toy computations on the $2D$ Ising model on a square lattice. I want to apply a renormalization transformation, and try to estimate observables on the renormalized lattice using Monte Carlo. My approach is as follows until now: I know how to generate configurations of the original lattice using ... |
A couple of months ago I was asked on an exam to calculate the Christoffel symbols of the following metric
$$d s^{2}=\left[1-\omega^{2}\left(x^{2}+y^{2}\right)\right] d t^{2}+2 \omega y d t d x-2 \omega x d t d y-d x^{2}-d y^{2}-d z^{2}$$
given the inverse metric
$$g^{\mu \nu}=\left(\begin{array}{cccc}
1 & \omega y &... |
Norton's dome demonstrate Classical non-determinism.
I am wondering if there is "quantum version" of Norton's dome?
In other words, is there any Hamiltonian where Schrodinger's equation is non-deterministic?
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I am trying to find how total solar energy incident, over a year, depends on the orientation of a tilted solar panel. The final goal is to find the optimum direction in which the panel should be pointed and the relative energy loss for deviations from that direction. So far, I have found an equation of incident intensi... |
I am studying Peskin and Schroeder, at page 287 , Lagrangian for scalar field is
$$L={1\over 2}(\partial _\mu \phi )^2-{1\over 2}m^2 \phi^2.$$
It can be rewritten as
$$L={1\over 2} \phi (-\partial^2-m^2)\phi . $$
I don't understand how it is rewritten,
Your little helps may save my lot of time.
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I am currently studying general relativity from James Hartle's book and I have trouble understanding how he goes to equation (5.60) from equation (5.58). It's about the variational principle for free particle motion from special relativity.
Here is the problem. First we have
$$L = \biggl[\biggl(\frac{dt}{d\sigma}\biggr... |
I'm working on the process $e^-+e^+\rightarrow ZZ$, taking into account Yukawa interactions, at tree level. Below is the diagram I got for the interaction with the Higgs. I want to write its corresponding amplitude and thus need to include the polarization vectors of the outcoming Z bosons, but since they are attached ... |
I was reading Longair its stated that,
"An important conclusion was that, if dark matter particles were as common as neutrinos and photons,their rest mass energies could not be much greater than $10eV$, or the present density of the Universe would exceed the critical mass density $Ω_0 = 1$. Therefore, there would have... |
Can we predict the positive parity, and zero spin of the Higgs boson from
the decay mode: →
|
The formula for calculating the number of images formed when two mirrors are placed at an angle $\alpha$ is $360/\alpha$. My question is how many images will be formed when it is a fraction? My teacher told to apply greatest integer function but in some places it says nearest even integer. So can someone please tell wh... |
Let a string with linear density $\rho$ and tension $k$ Its left and right hand ends $ [-\pi,\pi]$ are held fixed at height zero (Maybe not at $t=0$, but it are for $t>0$).
Initial velocity $v_0(x)\equiv 0$ and
$u_0(x)= x$. Find $u(x,t)$
What I did
I find by the boundary conditions
\begin{equation}
u(x,t)=\sum... |
I am struggling to understand the argument for why the introduction of a stop in SUSY can solve the hierarchy problem. The quadratic divergence from the top loop in the higgs mass calculation gives a contribution of
$$
\delta m_h^2 = - \frac{|y_f|^2}{16\pi^2} \left[2\Lambda^2 + \ldots \right]
$$
If we introduce a scala... |
I am currently studying about Fisher Information and have a rather simple doubt which I can't figure out.
Is it possible to have Quantum Fisher Information (QFI) more than Classical Fisher Information (CFI) for a system? What would be the implications, if so?
I am thinking that this is possible when we have entanglem... |
I was reading Sean Carroll book "Space-Time and geometry", in the appendix B he derives the energy momentum conservation from the diffeomorphism invariance of the action, however I don't understand a step in the derivation.
I will put some context before asking the question.
He starts with the action for matter field... |
I know of thermal hall effect which refers to a charge-neutral excitations exhibit hall effect that transport heat: for example, a heat current along x-direction generates a temperature gradient along y-direction when a system is in a magnetic field.
I recently saw an abundance of other hall effects, among which there... |
In a two body system both carrying current thus constituting a magnetic field, so will the mutual inductance of the system be equal to the mutual inductance due to body 1 on body 2 and vice-versa. If that is true, does that mean flux due to body 1 on body 2 is equal to flux due to body 2 on body 1?
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In yang-mills theory , the constraint algebra closes to form a lie algebra. Even string theory has a constraint algebra which closes to form a lie algebra. I wish to know if there are other cases where the constraint algebra doesn't close. What does it physically mean for the constraint algebra to not close ?
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Consider a null-killing vector $\xi^{\mu}$. Now due to the killing equation we have $$\nabla_{\mu}\xi_{\nu}+\nabla_{\nu}\xi_{\mu} = 0$$. Now I constract one of the index with $\xi^{\mu}$ to obtain
$$\xi^{\mu}\nabla_{\mu}\xi_{\nu}+\xi^{\mu}\nabla_{\nu}\xi_{\mu} = \xi^{\mu}\nabla_{\mu}\xi_{\nu} = 0$$ The second term vani... |
I am a math student and I am taking my first physics course of Mechanics. But I don't know the difference between the $w=mg$ force and $F=G\cfrac{m_1 m_2}{r^2}$ (why we don't use the first one when talking about the interaction between our planet and me).
For me, the two forces are related since $g$ is the gravitation... |
In most textbooks, a typical formation of a stationary wave is from a vibrating source in a medium that has a closed-end on the other side. In which the reflected wave will be coherent, with the same frequency and wavelength as the original wave produced by the vibrating source. But if I were to replace the closed-end ... |
Is the gravitational acceleration we consider only the attraction due to the Earth's gravity or is it that of gravity plus the attraction due to Earth spinning?
We know that earth produces an acceleration towards the centre on any body near it
due to gravitational attraction.
We denote this acceleration as $g$.
But w... |
Recently I came across a question which involved two coaxial, non conducting, uniformly charged discs, each having a surface charge density $\sigma$.
I was required to find the electric flux through one disc due to the electric field of the other disc and vice-versa.
The solution somewhat confused me. It claimed that ... |
In an astrophysics context about BAO (Baryonic Acoustic Oscillation), it is written on the following paper BAO paper :
"BAO are much smaller in amplitude than the CMB acoustic peaks, and are washed out on small scales. BAO in the observed galaxy power spectrum have the characteristic scale determined by the comoving so... |
In the theory of superconductivity, the phonon-mediated electron-electron scattering leads to an effective interaction, the BCS hamiltonian,$$\hat{H}_{\rm BCS}=\sum\limits_{\vec k,\sigma}\epsilon_{\vec k}c^\dagger_{\vec k,\sigma}c_{\vec k, \sigma}-\kappa^2\sum\limits_{\vec k, \vec k^\prime}c^\dagger_{\vec k,\uparrow} c... |
In all the books I read, only the initial speed with which an electron is removed from a plate is mentioned, what happens to the acceleration?
Consider a plate (charge neutral and not connected to anything) and light of appropriate wavelength hits the plate
Suppose that an electron is removed from the plate, it leaves ... |
Permanent magnets shows magnetic properties due to arrangement of domains in it.
Now when we bring a strong magnet [Assume $B=1\mathrm{T(tesla)}$] near a weak magnet [(Assume $B=0.0025\mathrm{T(tesla)}$],Strong magnet will rearrange the domains in weak magnet and will attract both the poles of weak magnet.
Now similar... |
The equation of motion of a particle in Newtonian mechanics in 3D under an arbitrary potential $U$, is written as $$m\frac{\mathrm{d}^2 \mathbf{r}}{\mathrm{d} t^2}=-\nabla U.$$ Now, my question is, how can this be generalised to Special relativity?
I know that the naive answer, $$m\frac{\mathrm{d}^2 x^{\mu}}{\mathrm{d}... |
Kirchhoff's law states that the sum of voltages around any closed loop sum to zero. The law is true as the electric field is conservative in circuits. Why can we not apply the law here?
Why doesn't the law hold here despite the fact that the electric field is conservative and the voltages should add up to $0$?
|
I know this topic has been asked alot, but I'd still like to ask a question to clear possible misunderstandings I have about the period of time before the bird physically lands on the wire, because I've seen some (I think) terrible answers and some good ones and I'd like to clear up any misunderstandings.
My understand... |
Here are some examples from my textbook I will refer to, which I could not copy paste,
I understand that $E=mc^2$ applies fine for thinking about rest energy, but when the body is not at rest, would this be the change in fictitious "relativistic mass", or is this a legitimate phenomenon? In example 1, this would then ... |
I am a student of class 11 and I have a doubt about reflection of waves on a string tied to a massless ring which can slide on a frictionless rod. When the wave reaches its end, the ring overshoots its amplitude because there is a lack of restoring force on it, as is written in the book Concepts of Physics. And in some... |
I've been working through the chapters in Schwartz on the renormalisation of QED, and I have some confusion to do with the form of the Vertex correction. By my understanding, the correlation function can be expressed
\begin{align*}
\left<\Omega\right\vert T\{\hat{\psi}(x_1)\hat{A}_\nu(x)\bar{\psi}(x_2)\}\left\vert\Omeg... |
Let the GUT symmetry $SU(5)$ break spontaneously to $SU(3) \times SU(2) \times U(1)$ at a scale $M$ much higher than the masses of $Z$ and $W$ bosons. Then, at this scale, $Z$, $W$ bosons can be regardedless virtually massless (let alone other lighter particles) so that $SU(3) \times SU(2) \times U(1)$ can be regarded ... |
Consider the wave equation,
$ y = A sin(kx-wt)$
I understand that taking the partial derivative of this function with respect to time gives the rate at which a particle at some distance 'x' oscillates.
However, I do not understand what it means to take the partial derivative of this function with respect to x. And, I'd... |
If I have an accelerometer at rest on Earth, and another placed inside a rocket which is accelerating, we will find that the observer in the rest frame and the one in the rocket both agree that the rocket shows acceleration on the accelerometer, while the Earth accelerometer does not. This is what would happen in real ... |
Emf is the work done to move a charge across the whole circuit. If i have a resistor wont the work done to move the unit charge increase?
|
I want to ask that, is there any intuitive way one can understand that why $\oint \mathbf B\cdot \mathrm d\mathbf l$ across a closed loop is $0$ when a wire not enclosed by the loop has current flowing through it.
In other words why do external currents don't matter?
|
I understand that the torque on a dipole due to a non uniform electric field is given by the same expression as that of in a uniform electric field i.e. pEsinθ. Now,how do you calculate the work done in rotating this dipole. I tried to integrate pEsinθ.dθ from limits say θ1 to θ2. But since the electric field is not un... |
Take a circuilar coil and a rectangular coil. Change magnetic field through them.
Due to circular symmetry electric field of same magnitude
is induced all over the coil.But in rectangular coil there are different magnitudes of different electric fields induced due to absence of circular symmetry.
My doubt is-" How elec... |
What will happen if diffracted light encounters another aperture in its path and gets diffracted once again? What will be the final result? How it will be different from the one-time diffraction pattern? Does anybody know any references?
Thank you in advance.
|
All other things being equal, a car with wider tyres is less likely to skid on a dry road than one with narrower tyres. As answers on related topics have made clear, the simple formula $F=\mu N$ does not apply to car tyres. We observe that when a car skids on a dry road, some rubber is left on the road.
Is the failure... |
The inner pipe (colored in red) radiates considerable more heat than the current one so I'm planning on extending the more thermally conductive one so that it heats better.
Will removing the outer pipe provide more heating to the environment?
Consider that the air that gets trapped in between both pipes does not circul... |
Thumb rule and right hand rule are for conventional current or electron flow ( for finding N, S in wire and winding)?
In a real experiment for finding true N , S what should I do?
|
In the rolling of steel, a sheet of steel is compressed plastically, so that it is thinner upon exit than at entry. This necessitates a change in velocity to maintain mass flow. As a result, certain portions of the roll can be considered pushing or pulling the strip from friction due to mismatch between the velocities.... |
I observed that in "interferometry" is used a process called phase unwrapped. This process can be done by using complicated algorithms but I was not able to found an example more simplistic. If somone could help or provide some examples in this direction will be nice.
Thank you :) !
|
I have this problem:
An object $A$ of mass $48\: \text{kg}$ hits with a velocity of $7.0 \:\text{ms}^{-1}$ another object $B$ which is not moving. After the collision the two objects move together at the same velocity of $1.4\: \text{ms}^{-1}$. What's the mass of $B$? What's the impulse applied on $B$ during the coll... |
When I study math for physics applications I always have some trouble in understanding why it's necessary to abstract the objects we study (vector spaces, scalar product, manifolds, groups...). In the beginning I thought it was to demonstrate theorems in a way that is valid for many cases but then I noticed it's also u... |
I am looking for the advanced quantum field theory PDF by David Tong, possibly called symmetries and particle physics. I have his quantum field theory PDF and am looking for his PDF on advanced quantum field theory, although I don't know what the title is.
|
I am currently studying the path integral formulation of quantum mechanics and have done a couple of problems (free particle and simple harmonic oscillator). Now, I am already done calculating the propagator for the simple harmonic oscillator and have shown that in the limit $\omega \rightarrow 0$ this gives the propag... |
Surface tension acts towards the centre of an air bubble. However, since surface tension is the result of the cohesive forces between the water molecules, should not the water molecules at the interface with the air bubble be directed towards the surrounding water molecules and not the centre of the bubble?
|
I recently read (Section 9.3 of J.Kaplan AdS/CFT notes) that we can have QFT's s.t. we have conserved charges but NO associated conserved currents. How is this related to the gauging of global symmetry? How is the charge even defined without the existence of a conserved current?
An explicit example is given: If in the... |
According to diagrams like this the answer is no, because every part of the objective lens gives the whole image. But when I cover part of the objective lens of my binocular, I only see part of what I see without covering. This shows that the answer to the above is yes.
|
I have an expression with two Wigner $D$-matrices $$\mathcal{D}^{j_1}_{m'_1,m_1}(\phi,\theta,-\phi)\mathcal{D}^{*j_2}_{m'_2,m_2}(\phi,\theta,-\phi)$$ and I would like to write the second matrix in terms of $\mathcal{D}^{j_2}_{m'_2,m_2}(\phi,\theta,-\phi)$ so that I can use the expression
$$\mathcal{D}^{j_1}_{m'_1,m_1}(... |
When you are inside some non uniformly and non radially polarized sphere, why do the dipoles from outer shells don't affect you (the potential there is only due to inner dipoles from what I have seen)?
|
I’m reading Isham’s Lectures on Quantum Theory, and in Chapter 5, General Formalism of Quantum Theory, Section 5.1.2, he states the following rule.
Rule 1. The predictions of results of measurements made on an otherwise isolated system are probabilistic in nature. In situations where maximum amount of information is a... |
The CERN tunnels use klystrons to accelerate the protons
https://home.cern/science/engineering/accelerating-radiofrequency-cavities
But electron guns use an electric field to accelerate electrons. Theoretically, shouldn’t we be able to use the same device to accelerate protons? The Output of this design would be a con... |
In a charged ring the distance of R/root(2) from centre there is maximum electric field due to it. I know that mathematics provides a quite legitimate answer to it but I just cannot find a conceptual answer. Similarly in a system of two opposite unequal charges with a greater positive charge, the point beyond which fie... |
I just studied the theory of angular momentum in non-relativistic quantum mechanics, which defined angular momentum as generators of Lie group $SO(3)$. And by using the Lie construction relationship, we can deduce that the eigenvalues of angular momentum in 3D can only be integer or half integer.
Now I'm wondering wha... |
I have a decent idea of how colliders like the LHC work, but I'm not sure what the value is in continuing to run them.
Once you've smashed all of the (not very many) light elements together at a range of speeds and angles and collected the data, what else is there to do apart from look at the data for one or another th... |
So to get a proton beam for the LHC, CERN prob has to make a plasma and siphon off the moving protons with a magnet. Are the electrons stored somewhere? How? I don’t mean to sound stupid but when they turn off the LHC, all those protons are going to be looking for their electrons. And that’s going to make a really big ... |
As by the Wikipedia definition, an OPE in QFT is a convergent expansion of the product of two operators at different spacetime points in terms of a sum of (possibly infinitely many) local operators.
In Conformal Field Theories it can be proven that the radius of convergence of this series must be at least as big as tha... |
Essentially, I'm designing a drop test, and to simplify my problem I've modeled the system as a known mass $m$ being dropped from a set height $h$ onto a spring (set $k$), compressing it ($x$). How many $g$'s does the mass see upon impact, when the spring is fully compressed?
Using energy equations to solve for $x$ is ... |
In deriving the Electromagnetic wave equation in free space we remove all charge sources. The resultant Maxwell vector equations are thus source-free. Using Gaussian units with the speed of light $c=1$, these equations are written as:
\begin{align}
\nabla \cdot \mathbf{E} &= 0\\
\nabla \cdot \mathbf{B} &= 0\\
\nabla \t... |
In QFT the asymptotic states play a very important role, as they are the basis on which we decompose our in-states and out-states when we calculate correlation functions.
However, I have not been able to find a good description that accommodates QFTs at arbitrary coupling. Most definitions assume that the theory is in... |
I am reading a research paper on how to calculate g-tensors* computationally (Correlated four-component EPR g-tensors for doublet molecules).
In the theory section, they write "[...]from (quasi-)degenerate perturbation theory one gets an expression for the first order energy corrections":
$$\begin{aligned}
E_{i j}^{(1)}... |
Is there a smooth way to derive the Feynman rule for the interaction term
$$\mathcal{L}_{int}=gA_{\mu}A^{\mu}A_{\nu}A^{\nu}?$$
$A_{\mu}$ denotes a massive vector field.
|
Can a wave exist within a black hole? A wave implies motion (amplitude and frequency) but motion can not occur without the passage of time. A wave also implies wavelength that cannot occur because gravity does not allow for any outward motion. Therefore, can a wave even exist inside a black hole?
In this forum we al... |
Suppose we have two distinct states $\rho,\sigma\in \mathcal{H}_A$. Define the following state
$$\omega = \frac{1}{2}(\rho^{\otimes n} + \sigma^{\otimes n}) \in \mathcal{H}_A^n$$
Let $\mathcal{H}_R\cong \mathcal{H}_A$ and let $n$ copies of $\mathcal{H}_R$ be used to purify $\omega$. After playing around a bit, I think ... |
Suppose we have a system which can take different states, characterized by energy $E$ and degeneracy $\gamma(E)$. The energy of each state is characterized by an order parameter $r$, such that $E=E(r)$. By using the microcanonical ensemble one finds that each state has an entropy of $S=S(r)$.
In my exercise I have an ... |
I am studying how to derive the cross section out of S-matrix elements from the beautiful book Quantum Field Theory by Mandl and Shaw (second edition; chapter 8, section 8.1) and there are several steps I do not get.
We first consider two particles (they may be either leptons or photons) with initial (i.e. before colli... |
I am currently studying the textbook Infrared and Raman Spectroscopy, 2nd edition, by Peter Larkin. In a section entitled The Raman Scattering Process, the author says the following:
Both Rayleigh and Raman are two photon processes involving scattering of incident light ($h c \bar{\nu}_L$), from a “virtual state.” The... |
As a two-level atom evolves in accordance with the Optical Bloch Equations in a laser field, how do I calculate the change of the field evolution due to the fact that atom absorbs and emits photons?
|
In this article they show the following diagram:
Are all the diagrams in the little boxes really just Gaussian probability density functions with mean and variance (or covariance)? If not, what kind of density functions are these? Is there a name?
|
The scalar magnitude $S$ of a symmetric 2nd-rank tensor $S_{ij}$ in a given direction having direction cosines $l_i$ is given as:
$$\tag{1} S=S_{ij} l_i l_j$$
This result is obtained by starting with Eqn(2) and using the relationship given by Eqn(3):
$$\tag{2} S=\frac{|\mathbf{p}|\cos \theta}{|\mathbf{q}|}$$
$$\tag{3} ... |
Persistent current is the current which flows forever in a superconductor.
In picture we have two conductors. In figure "A" we have a round superconductor and when we give voltage to it and then disconnect the voltage, current will flow round and round forever and it makes sense.
But in figure "B" we have a straight co... |
I have seen many questions in the famous Indian "JEE exam" which involves a system being given a small disturbance and then oscillating in simple harmonic motion due to it.
Examples:
A horizontal wire AB which is free to move in a vertical pane and carries a steady current is in equilibrium at a height $d$ over anoth... |
Homogeneity is the idea that the universe looks roughly the same no matter where the observer is. This paper on whether the universe is homogeneous includes this line:
A common misconception is that ‘homogeneity is obvious from the cosmic microwave background (CMB) and the galaxy distribution’. In fact, we cannot dire... |
Given the magnetic field strength of a magnetic field generated by a superconductor, how could you calculate the total volume that this field encompasses?
The main reason I'm asking this question is as superconductors exclude magnetic fields from its interior, I'm wondering how this changes anything in the process of c... |
I am currently studying the textbook Infrared and Raman Spectroscopy, 2nd edition, by Peter Larkin. In a section entitled The Raman Scattering Process, the author says the following:
The intensity of the Raman scattered radiation $I_R$ is given by:
$$I_R \propto \nu^4 I_o N \left( \dfrac{\partial{\alpha}}{\partial{Q}}... |
2D oscillator
$H_0=\frac{P_x^2}{2m}+\frac{P_y^2}{2m}+\frac{1}{2}m\omega^2\left(x^2+y^2\right)$
with perturbation
$H_1=h\omega \left(\frac{L_z^2}{h}-2\right)$
How to write the perturbation in terms of the creation-annihilation operators?
This is different and I don't know how to deal with $L_z^2$
|
In quantum mechanics, it is postulated that to every observable, we have an associated operator. It is further postulated that when we do a measurement on a system, the measured value is one of the eigenvalues of the operator (operator corresponding to the observable), and the wave function (which is initially superpos... |
I have a question which asks how a compass needle would align when placed between 2 current carrying solenoids.
The answer is apparently:
The north pole of the compass would point up the page.
The compass would align with the magnetic field (which points upwards), produced by the two solenoids whose inner ends both... |
Let us take two unlike point charges $q_1$(positive charge) and $q_2$(negative charge). When we decrease the distance between them, the potential energy between them also decreases according to the formula $U=k(q_1q_2)/r$.
Here the conservative force is the electrostatic force which is responsible for the decrease in p... |
I am currently trying to find the temperature drop of a decompressing gas canister for rocketry club to make sure that it doesn't get too cold to affect nearby components like electronics.
The canister starts out at 6000 psi, and drops to 1000 psi by the end as the helium inside is used up as pressurant for another tan... |
Let's say there are 2 scenarios:
A man walks to the wall and then he hit the wall and feels pain.
A man pushes the wall and of course, his feet start moving in the opposite direction.
(No friction)
From these two scenarios, which one caused by Normal Force or Newton's 3rd Law.
Or in another word, what caused the man ... |
Consider a two-point correlation function defined as $$G_{ij}({\bf x},{\bf x}^\prime)\equiv \Big\langle\Big(\mathscr{O}_i({\bf x})-\big\langle\mathscr{O}_i({\bf x})\big\rangle\Big) \Big(\mathscr{O}_j({\bf x^\prime})-\big\langle\mathscr{O}_j({\bf x^\prime})\big\rangle\Big)\Big\rangle\tag{1}$$ $$~~~~~~~=\big\langle \math... |
Is it physically possible to substantially change a large magnetic field with a smaller one analogous to the electric field at the gate being able to partially or completely block the flow from source to drain in a transistor?
I'm imagining being able to reorient the field from a rare earth magnet using less powerful e... |
In Griffith's Electrodynamics (Third Ed.), on page no. $176$, it is written:
It may have appeared to you that I left out the surface bound chrage
$\sigma_b$ in deriving Eq. 4.22, and in a sense that is true. We
cannot apply Gauss's law precisely at the surface of a dielectric
sphere, for here $\rho_b$ blows up, ... |
We know that the density of of water at $4°\rm C$ is maximum $1\rm\: g/cm³$. But how is it possible??
Suppose I have $1kg$ of water at $4°\rm C$ .So it's density is $1\rm\: g/cm³$. But what if the temperature is lower than $4°\rm C$? The volume should decrease and since the mass is not disturbed, the density should ... |
In the Einstein's model of time-space bending, in the simplified version, the fabric of the Universe is in 2D, while the planets are in 3D. This is the first inconsistency that I think ruins the explanation of the model. You can't arbitrarily dimensionaly downsize one part and not the other, you get a dimensionaly inco... |
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