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Supersymmetric transformation:
$$
\begin{align}
\delta\Theta^{Aa} =& \varepsilon^{Aa}, \tag{5.3} \cr
\delta X^\mu =& \bar{\varepsilon}^A\Gamma^{\mu}\Theta^A. \tag{5.4}
\end{align}
$$
The combination
$$\Pi^\mu_\alpha := \partial_\alpha X^\mu
- \bar{\Theta}^A\Gamma^\mu\partial_\alpha\Theta^A,\tag{5.7} $$
is changed as... |
A resistance, by definition offers restriction to the flow of current. Thus when propelling a charge through a resistance, we have to do more work. Therefore shouldn’t the work done per unit charge, i.e, voltage, increase?
|
I am looking for an advanced graduate level book in classical electrodynamics.
An example of such a book is by I. Tamm (possibly it exists only in Russian). But I would be interested to have more references.
|
Let's say, I have a vacuum chamber of diameter D and height h. I have filled 1/10th of the chamber with water. Now I have two questions:
1.How long and how much water will boil or evaporate if the pump is turned on forever? Will all of the water be vaporized?What's the rate of vaporization(kg/sec)?
2.How long and how m... |
I recently came across the chapter of hydrostatics and read about Pascal's Law,which states that: "a pressure exerted in a confined liquid is transmitted equally and undiminished in all directions."
There was an experiment given along with that to show it.
But that experiment did not satisfy me and so I wanted to know ... |
I was curious about the famous $p=\hbar k$ equation. In high school I think you are just exposed to this equation with the explanation of "something something matter waves." But early in a undergraduate QM course you solve the time-independent Schrodinger's equation for a free particle in 1D and get the following solut... |
I am looking for a free simulating tool for the propagation of waves given constraint. I am assuming a scenario with a source, a receiver, and some constraining reflecting\absorbing surfaces (metal surfaces or enclosures for radio waves for example). Given a signal emitted from the source, I want to simulate the signal... |
We define acceleration as $-9.8\frac{m}{s^2}$ for an object that is thrown upwards due to gravity. My question is when the object reaches maximum height at the point where it is about to turn around downwards, will the magnitude of the acceleration still be $9.8\frac{m}{s^2}$ or will it be greater than this as to help ... |
When charged particle inside a media moves faster than the speed of light of that media, a faint bluish glow is observed which we call as "Cherenkov radiation". It is a very common scenario in nuclear power plant. I have been told that the high energy particles polarise the dielectric media (water) while traversing thr... |
I came across the following in my physics text-book while reading alternating currents:
Average value of current is given by:
$$I_{av}=\frac{\int_{t_1}^{t_2}{I(t)dt}}{t_2-t_1}$$
Over a long period of time, the denominator tends to a large value, and the numerator a finite one.
$\therefore$ The average value of the a... |
In 1+1D, a spontaneous symmetry breaking of a finite group $G$ gives rise to critical point. What is the CFT for such a critical point.
|
The assumption that a fluid is incompressible seems to be an extremely common (and useful!) approximation to model fluids. I'm wondering what physical properties of a fluid make it approximately incompressible.
For example I can convince myself that a fluid with an extremly large (infinite) amount of internal energy wi... |
I came across a question today about vapour pressure, it was as follows :
$2$ flasks $X$ and $Y$, each containing liquid water, joined by a tube connecting their mouths (no vapour could escape) having a valve in the middle were immersed in water baths of $300K$ and $350K$ respectively, which were used to ensure that th... |
According to the statistical interpretation of Quantum Physics, a particle does not have a precise position regardless of any measurements. But then, the interpretation imposes another condition on the wavefunction of a quantum object - The integral of the wavefunction squared should be equal to one i.e. the total prob... |
I'm doing some exercises on $LS$ coupling during my self-study of atomic physics. I understand how to construct a table of possible microstates. I also understand how to map term symbols to those cells of microstates: the total wave function must be antisymmetric under exchange of both electrons. Combining the fact tha... |
This topic really screwed with my head in school and my teacher could never answer my questions so I thought I would ask here. I will break it down with mathematics and then logic.
Let's assume we only have 1 body which is earth and nothing else exist.
We can work out the escape work done using this formula where $m = ... |
Suppose we have a tuning fork, we know it will vibrate at a constant pitch(frequency). Let's say the tuning fork is of 440hz, so I imagine the prongs of the fork to be vibrating 440 times per second, but how does an object that will have a fundamental frequency plus added overtones vibrate physically?
Bonus question : ... |
Let's suppose that through engineering, a third bionic eye would be attached to a human and interfaced directly with the brain. Let's assume this third eye is positioned in the middle of the forehead.
If all three eyes are being utilized by the brain and their images merged, would this give us a better depth vision?
|
Can a finite simple symmetry group $G$ be spontaneously broken in stages, with two or more phase transitions, each one leaving a successively smaller unbroken subgroup?
By simple, I mean no normal subgroups. This excludes product groups, which clearly can be broken in stages.
I'm especially interested in the case of $1... |
For a pendulum to easily demonstrate the Foucault effect, it should
have as long a cable as possible (this one is 52 feet) and a heavy
symmetrical bob (this one is hollow brass, weighing about 240 pounds).
https://www.si.edu/spotlight/foucault-pendulum#:~:text=Any%20pendulum%20consists%20of%20a%20cable%20or%20wire,one... |
I'm going through Lenny Susskind's QM: The Theoretical Minimum course and I was wondering if the numbers used to represent quantum states, like spin up as $\begin{bmatrix} 1 \\ 0 \end{bmatrix}$ and spin down as $\begin{bmatrix} 0 \\ 1 \end{bmatrix}$, have any physical significance? Do they have to satisfy any condition... |
$$
{\partial (0.5 (\partial_{\mu} A^{\mu})^2) \over \partial(\partial_{\mu} A_{\nu})} = {(\partial_{\rho} A^{\rho}) g^{\mu \nu} }
$$
Can somebody explain why this is true?
|
The lagrangian is always phrased as $L(t,q,\dot{q})$.
If you magically knew the equations $q(t)$ and $\dot{q}(t)$, could the Lagrangian ever be written only as a function of time?
Take freefall for example. $$y(t)=y_0 + v_0t -(1/2)gt^2$$ $$\dot{y}(t)=v_0 -gt$$
Can the Lagrangian now be written as: $$L=KE-PE=(1/2)m\dot{... |
In this paper Matthew Fisher proposes the use of so-called Posner molecules for quantum processing in the brain. I am trying to understand the arguments at the beginning of Section F (Section 6 in the published version here):
Consider first the spin and rotational states of a single Posner molecule. Quantum chemistry ... |
I know that salt decreases the freezing point of water. We have freezing point (in Celsius), $\mathrm{T_f=-K_f\cdot m}$ (molality of salt). But, is it true that all of the solution doesn't freeze at the same temperature? (i.e. either parts of the ice form at temperature less than $0^\circ C$ but greater than $T_f$ or t... |
My current understanding is that if a sound has a pitch it must be periodic, i.e. it is composed of sound waves that have frequencies. So I assume that means there must be a fundamental frequency.
Also, I assume that no sound which is not periodic will have a pitch or a fundamental frequency.
Please let me know if I'm ... |
The legend himself, John Rennie, spent several hours in chat to convince me that if the slit width in a single slit diffraction pattern is doubled, then the intensity at the central point becomes $4$ times. Although I agree with , (and understand) his method, I have a different perspective:
The intensity is the magnitu... |
Despite being presented as one of the fundamental results of Quantum Mechanics in practically every textbook, I realized this morning that I don't understand deeply how Quantum Mechanics predicts the double slit experiment.
The best explanation I have found seems to be closely related to the path integral formulation (... |
What is the best way to understand that the magnetization work has the form
$$\delta W=HdM?$$
On a side note: Is this even the correct formula, or should one rather use
$$\delta W=BdM?$$
I'm guessing the difference comes from assuming only weak magnetization, so that $$B=H+M\propto H$$ but I'm not sure.
|
Let me give an example at first: All of the calculations that are carried out in quantum chemistry rely on approximation methods to the Schrödinger equation. While these methods sometimes give quite good approximative results, they are computationally very hard.
I wonder whether one could find a theory, which agrees wi... |
Imagine you are watching a YouTube video where a nuclear bomb goes off. Exactly six seconds later, the shockwave arrives and hits an object that is some distance away. How would you go about calculating the distance between the bomb and the object? Now, naturally, you would be tempted to take the six seconds and multip... |
In normal functioning of household power supply, the current flows through the hot and the neutral wire. Why does it not take the path of the ground rod, even when the ground rod, neutral wire and the ground wire are all connected to the same neutral bar?
I think this is because to complete the circuit the current woul... |
Sub-question if Yes: de Broglie wave is also often called the matter-wave. While we can find the frequency of an Electromagnetic Radiation from its wavelength $(c=\nu\lambda)$. $c$, in this case, is the speed of light in the vacuum which is a constant. Does a similar constant exist for matter that can be substituted? (... |
Is it possible to define and calculate chern number for two bands while they're crossing each other?
|
I am looking at the tensor product of $n$ spin halfs (fundamental of $SU(2)$):
\begin{equation}
\left(\frac{1}{2}\right)^n = \frac{1}{2} \times \frac{1}{2} \times ... \times \frac{1}{2} = \frac{n}{2} + ...
\end{equation}
For example, for $n = 3$
\begin{equation}
\frac{1}{2} \times \frac{1}{2} \times \frac{1}{2} = \frac... |
I am currently studying the textbook Modern optical engineering, fourth edition, by Warren Smith. Section 1.5 Interference and Diffraction says the following:
Now if the waves arrive at C in phase, they will reinforce; if they arrive one-half wavelength out of phase, they will cancel. In determining the phase relation... |
I'm passing a 1392nm laser through a beamsplitter, through an aresol medium hitting a retroreflector, passing back through an aresol medium, and passing it through the same beamsplitter. The two beams split toward two respective photodiodes, and the final transmitted beam is irrelevant; the laser has an isolater, so it... |
Why is the finesse of a fabry-perot resonator given by $2\pi/\text{RTL}$ while the finesse of a ring resonator is given by $\pi/\text{RTL}$?
The finesse of a fabry-perot resonator is given by $F = 2\pi/-\ln(R_1R_2)$. (source: wikipedia) For high enough reflectivity $-\ln(R_1R_2) \approx 1 - R_2 R_2$, so $ F \approx 2\p... |
In Matthew D.Schwartz book, 'Quantum Field Theory and the Standard Model' page 227/8 he talks about Feynman diagrams in QED, specifically $e^{-}e^{-} \rightarrow e^{-}e^{-}$ u and t channel tree level scattering amplitudes.
He then proceeds to say that these two diagrams represent contriubtions to the fourier transform... |
I am trying to understand coordinates on the space $T^{1,1} = SU(2) \times SU(2) / U(1)$, which shows up in applications of AdS/CFT. It was originally introduced by Romans as a compactification of $d=10$ supergravity. My confusion is that there seem to be two contradictory conventions in the literature for constructing... |
I am following an example in the book "Electromagnetic Waves and Antennas" by S. Orfanidis. He has two planes waves incident on both sides of a boundary. Here, $k_{\pm} = \hat{x} k_{x \pm} + \hat{y} k_{y \pm} + \hat{z} k_{z \pm} $ is the forward and backward propagation vector for the left medium and $k'_{\pm} = \hat{x... |
I want to show that the free Wess-Zumino Lagrangian is invariant under a SUSY transformation, e.g. following this reference (section 3.1).
However, I have a hard time understanding the daggers and stars on the fields. In particular, with the fermionic fields. The fermion Lagrangian looks like this:
$$ \mathcal L_\text{... |
I am confused about the statement of how vector $\Delta \vec{v}$ is perpendicular to vector. I highlighted the statement in pink. I ended up copying the image of the right vector $\vec{v}$ in the velocity isosceles triangle and moved its tail to touch the tail of vector $\vec{v}(t)$. It does not look perpendicular so c... |
Suppose a galaxy is headed beyond the cosmological event horizon. Photons it emits now will eventually reach us, but there is a point at which photons will no longer be able to reach us.
Supposing that a finite number of photons are emitted, this would seem to imply that the galaxy will eventually vanish from sight. Bu... |
I know many of you are tired of book recommendation posts and questions. But I am self learning Theoretical Physics, and I am having a hard time choosing a book to learn differential equations (ODEs). I really want a good understanding of differential equations; I have been told that ODEs and PDEs are the language of p... |
As shown by the image, a disk of radius $R_1$ mass $M_1$ and initial velocity $V_0$ collides with another still disk of radius $R_2$ mass $M_2$. Both disks has no rotation initially. The direction of $V_0$ is indicated by $\theta$. For three situations there are unique solutions:
When $\theta = 0$, the problem beco... |
Usually I have been dealing with equilibrium that shows 2 hinges pulling a cable with a pulley in between, meaning that the hinges are at the same height and there will be same tension for both sides of the cable.
However, if I were to move one of the hinge upwards, how will I then calculate the tension of the cable ( ... |
Simple version
Consider if we have a Lagrangian defined by
$$L(q,\dot{q}) = \frac{1}{2} g_{ij}(q) \dot{q}^i \dot{q}^j - U(q) \tag{1a}$$
where the potential energy $U(q)$ has a single minimum at $q=0$ ($q$ here is a collection of coordinates). We are interested in studying the harmonic fluctuations about the minimum. De... |
Quantum materials are now an emerging field of study. I didn't actually understand the need for classifying materials as quantum materials and normal materials. Wave functions of electrons and their spins etc. in normal materials work under the principle of quantum mechanics only. Thus what specifically is meant by qua... |
According to Einstein's general relativity, massive bodies should cause gravitational redshift.
How accurately has this been measured?
|
Is there any practical meaning of the Fermi level? In the below image we can see how it behaves when p and n-material connect: It basically holds a constant value(?).
Can we draw any meaning out of that?
And (why/how) does it matter that the fermi level is closer to the conduction band in the n-side and closer to the v... |
Mass $m$ is rotating on a horizontal friction-less plane around a tiny hole. A massless string is connected to mass $m$ and the other end of it is held by John's hand. John pulls the string to move the mass to radius $r_2$, what is the angular speed $(\omega_2)$ of mass $m$?
I have 2 approaches to this:
1. Work & E... |
Although I’m rather new to physics and this site, I wanted to ask a question because it’s been sitting on my mind recently and I can’t figure it out... Forgive me if I’m missing something but here goes.
It is said that when an object approaches the speed of light, it’s mass increases very, very much. However, If an obj... |
I am going through section 2.4 and 2.5 of Walter Greiner's book "Quantum Mechanics: Special Chapters". In section 2.4, there is a detailed analysis of the elastic scattering of a free electron and a photon. In page 57 of section 2.4 Eq. 2.56 the book mentions that
$$
\frac{\text{Transition prob.}}{\text{Time}} \propto ... |
I recently read about Cherenkov Radiation and the neat blue glow it creates in underwater nuclear reactors, and my understanding of it is that it occurs due to particles ($\beta$ particles in the case I am about to describe) travelling faster than the speed of light in that medium.
Coming to Uranium glass, I know it is... |
I am facing a problem dealing with velocity when coordinate axis (origin) is shifted. Could someone please explain me how the velocity changes if the coordinate axis is shifted. For ex: I have a velocity vector or $3\hat{i}+3\hat{j}$ and then origin is shifted to $2\hat{i}+3\hat{j}$. Now does the velocity changes to $1... |
Is the potential energy of an isolated system of point charges placed in a bounded space in equilibrium necessarily zero?
|
I know that friction is cause by the electromagnetic force between electrons from 2 contacting surfaces but how come it only applies to physical contact with a solid surface?
|
What are the different reasons why theory of gravity mediated through gravitons fails?
|
I am following Sidney Coleman's lecture of Quantum field theory where in ch 25 he talked BPHZ renormalization and in ch 23 he talked about on-shell renormalization of spin-1/2 theory.
Let us take a theory of Fermi field coupled to a real pseudoscalar field through Yukawa interaction
$\mathcal{L} = \mathcal{L}_{free} + ... |
For example in a semi-inclusive inelastic scattering, a quark (inside a nucleon) can receive momentum fraction from the lepton that it interacted with. If the x value is high towards 1, the quark is most probably valence quark. Can we call it struck quark? How different it is than an active quark?
|
As a part of larger project, I decided to test my Lagrangian formulation of simple system of two rigidly connected point masses as indicated below.
I introduce the generalized coordinates vector $\bar{q} = [x, y, q]^T$, where $x,y$ are coordinates of position of mass $M$ and $q$ is the angular deflection from horizont... |
Consider an object resting on a surface. If I had to find the net force on the object, I would write an equation as follows: weight = normal force.
But what about the air pressure that's acting on the surface of the object? Since object is resting on a surface, there is no air pressure acting from below the object to c... |
Consider a pipe. The pipe is not crushed by the air pressure because the same air pressure is acting from inside the pipe. But this means that the material of the pipe is being compressed on both sides by some air pressure. So is it correct to say that the through-thickness stress in the pipe would be the same as the a... |
I don't fully understand the circular polarizer filter (CPL) for my camera. It contains a linear polarizer and a quarter wavelength plate (QWP). The QWP causes a time delay between the ordinary and the extraordinary component of the light wave. This delay should correspond to a phase shift of 90° to create circularly p... |
This question is motivated by Section 3.2.3 in Griffiths.
Therein, we are considering the force of attraction between a point charge and an infinite conducting plane. One can calculate the field using the method of images, and from that the force of attraction exerted by the induced charge to be $$\mathbf{F}=-\frac{1... |
I am reading the book Scattering Amplitudes in Gauge Theory and Gravity from Elvang and Huang. In section 2.6 they seem to suggest that the mass-dimension of the kinematic part of the amplitude is in 1-to-1 correspondence to the number of derivatives in the interaction term in the Lagrangian. For example, for the 3-glu... |
I was solving a electrostatic problem, I had to calculate the voulume charge density by using the equation,
$\rho=\epsilon_0\nabla\cdot\vec E$
$\vec E=\epsilon_0(\frac{\lambda Ae^{-\lambda r}}{r}+\frac{Ae^{-\lambda r}}{r^2})\hat r$
I got the divergence as
$\nabla\cdot\vec E=\frac{1}{r^2}\frac{d}{dr}(r^2E_r)=-\frac{\eps... |
Is lightning white due to moving electrons or nearby nitrogen,oxigen and water vapour atoms and can a simple lighter spark glow white?
|
According to this article, there is a large quantity of Helium in space (stars), but very little is accessible to us on Earth:
Helium is abundant in space, where it's produced as a product of the
fusion reaction inside stars such as the sun. The naturally occurring
helium on Earth, though, comes from a different sort ... |
I recently read about the early universe and found that first quarks were made $10^{-12}$ seconds after the inflation or the beginning.
But what was the cause of this minute delay, since inflation started when the universe was $10^{-34}$ seconds old (as per this image).
So basically I want to know why did it take that... |
The textbook argument against photons canceling each other draws upon the conservation of energy. Does this mean that energy conservation is a "stronger" principle than superposition? Waves in other media than the EM field, e.g., sound or water, do cancel out---presumably by passing on their energy to some other degree... |
This is to ask a more general question: Landau-Lifshitz say that for the variational principles
$$\delta\int_{t_1}^{t_2}p\mathrm{d}q-H\mathrm{d}t =0$$$$ \delta\int_{t_1}^{t_2}P\mathrm{d}Q-H'\mathrm{d}t =0$$ to be equivalent, the difference $(p\mathrm{d}q-H\mathrm{d}t)-(P\mathrm{d}Q-H'\mathrm{d}t)$ must equal the differ... |
I've seen (e.g. in Srednicki) the following notation for the connection between a Lorentz transformation $\Lambda$ and the Lorentz generators $M^{\mu\nu}$:
\begin{equation}
{\Lambda^\mu}_\nu = {\left( \exp \left( \frac{\text{i}}{2} \, \omega_{\alpha\beta} M^{\alpha\beta} \right)\right)^\mu}_\nu ,
\tag{1} \label{1}
\en... |
I am trying to prove that $$G(t-t')=\frac i{2w}e^{-iw|t-t'|}$$ satisfies $$\left(\frac{\partial^2}{\partial t^2}+w^2\right)G(t-t')=\delta(t-t').$$ (Problem 7.2 from Quantum Field Theory by Mark Srednicki.)
Using the fact that $\frac{\partial}{\partial t}|t-t'|=sgn(t)$ and $\frac{\partial}{\partial t}sgn(t)=2\delta(t)$,... |
Consider a circular current loop of radius R in which a current enters at a point A and leaves at point B through straight wires. Minor arc AB subtends angle 'theta' at the centre of circle. Now at any point located at a distance r from the centre, how can the magnetic field be calculated?
Would it be zero? Because all... |
In a relativistic context, the energy of a "single" photon, thought of as a massless particle with an on-shell condition $p^2=0$ or $E^2=\vec{p}^2$, depends on the frame. In other words, performing a boost preserves the light-like property of its four-momentum but it doesn't preserve the actual components.
If we consid... |
Consider a scalar field $(+,-,-,-)$ with the following Lagrangian density
$$\mathscr{L} = \frac{1}{2}\partial_\mu\phi\partial^\mu\phi + V\,.$$
The associated stress energy tensor is
$$T_{\mu\nu} = \partial_\mu\phi\partial_\nu\phi -g_{\mu\nu}\left(\frac{1}{2}\partial^\alpha\phi\partial_\alpha\phi - V\right)\,.$$
Compari... |
Is there a speed that object A can move at, such that object B would remain 'stuck' to the front of object A, due only to the air pressure as a factor of object A's speed?
I realise that friction between object A and B play a part, and that the shape of both objects could affect things, so how about both A and B are tw... |
How can one mathematically demonstrate that angular displacement is not a vector and is not commutative?
|
I am a mathematician and I am trying to understand the intension behind the inverse temperature and the activity (or intensity).
Consider e.g. the Hamiltonian [with (12,6)-Lennard-Jones pair potential] with some intensity parameter $z > 0$ and interaction parameters $\sigma > 0,$ $\varepsilon > 0,$ that is,
$$
H_{\Lamb... |
Most datasheets for photodetectors only specify the noise equivalent power, making no distinction between thermal noise (Johnson noise) and shot noise. For modelling purposes, how do I know whether the photodetector is shot-noise limited or thermal noise limited?
|
When no external electric field is applied, electrons move with thermal velocity and return to their initial position so displacement is zero. However, when an external electric field is applied, instead of moving back to their initial positions, do they drift little rightwards from their initial position? For example,... |
A light cord is wrapped around a wheel (a disk). It is pulled downwards in 2 ways. Case 1- By a steady downward force F. Case 2 - By attaching a weight equivalent to F. In the 2nd case, tension will be less. I am struggling to understand how tension will be different by the same magnitude of force.
|
This may be a silly question, but I don't know how to approach an answer myself and I can't seem to find the right search terms to input.
A simple rocket might be a compressed air bottle, where a reaction does not take place and the exhaust gas is the same form as the exhaust itself. Thrust is produced because the air ... |
It seems from many examples that momentum measurements inevitably involve position measurements. For example, if I want to measure the momentum of a charged particle, I pass it through a magnetic field and infer the curvature and hence momentum from the position measurements made by detectors placed around the region o... |
I have an upcoming undergraduate introductory QM exam.
The teacher is known to hold grudge against classes of students he doesn't like, so in an act of spite he gives them the hardest problems he can find. This exam is in two weeks, and we pissed him off good :) .
I want to get ready and I ran out of problems, so I ask... |
How can two particles be drawn together by exchanging other (force carrier) particles. Both reactive components of exchange and absorption logically seem to support repulsion. How are these particle exchanges responsible for attraction of the exchanging parent particles? Unable to find an online answer after considerab... |
Are there any formulas for wave motion on a topological surface, like a Mobius strip? If not, is this a valid opportunity for research?
|
Suppose $q = \{q_1,\cdots, q_i\}$ is a coordinate system for Lagrangian $L(q,\dot{q},t)$. In this text by David Morin, on page 16 in chapter 6, it states that a symmetry is a transformation of the Lagrangian coordinates, $q'_i = q_i + \varepsilon\cdot K_i(q)$, $\varepsilon$ small and where $K_i(q)$ is a function on the... |
I'm writing my bachelor thesis in CFT (without ever having taken any courses in any field theory) and I'm trying to figure out why in two-dimensional scale-invariant theory the conservation of a current allways implies that its $z$ and $\bar{z}$ components are seperately conserved. Where $z$ denotes the complex variabl... |
Looking at the blue sky using my polarizing sunglasses I notice an effect (details below), that seems to match well to this answer, where it is said:
The greatest degree of polarisation occurs when the scattering angle
is through 90 degrees (since one of the polarisation states of the
incoming solar light is effective... |
More importantly, what happens to the energy/information?
In most respects this should be the same as a black hole horizon?
Only even more weird, because here two masses gets "disconnected" from each other.
What happens to the potential energy stored between these two objects?
How does this energy increase if they are ... |
Consider the following model of an axion-like particle $a$ (or ALP):
$$
\mathcal{L} = (\partial_{\mu}a)^{2}/2 - m_{a}^{2}a^{2}/2 + ag_{a\gamma\gamma}F_{\mu\nu}\tilde{F}^{\mu\nu},
$$
where $F_{\mu\nu}$ is the EM field strength. $m_{a}$ and $g_{a\gamma\gamma}$ are independent constants. My question is the following. The ... |
In the derivation of the LSZ reduction formula we write asymptotic states using ladder operators at $\pm \infty$. For example if we consider for a real scalar field $\phi$ then we have the formula
$\sqrt{2\omega_p}\big(a^{\dagger}_p(\infty)-a^{\dagger}_p(-\infty)\big)=-i\int d^4x\space e^{-ip\cdot x}(\partial^2+m^2)\ph... |
When a mass rolls without slipping on an inclined plane, does the frictional force impart an angular acceleration whilst taking linear momentum out of the mass? Does the frictional force reduce the force on the center of mass whilst causing the object to rotate?
|
Question 1:
Which electron in the circuit moves first if you were to connect a wire to both ends of a battery simultaneously?
Is it:
The last electron in the wire, which is pulled into the cathode of the battery? And the rest of the electrons are "pulled"?
The first electron coming out of the electrolyte, and the rest... |
A previous question that I asked made me realize I had some major misconceptions about entropy. If I now understand this correctly, given the density matrix of a system, we can calculate Von Neumann Entropy, Renyi Entropy, or whatever other type of entropy we would like. These measures of entropy are all some sort of m... |
I would like to know the origin of the sub-bands in the non degenerate Hubbard model. Most of the texts consider the Hubbard model at half-filling. Is the emergence of the sub-band specific to the half-filling condition or is it also seen for arbitrary filling?
I am aware that the inclusion of the Coulombic potential i... |
If I take a piston (such as the classic expanding gas piston) with a constant weight on the plate and liquid water beneath the plate. I understand by Pascal's principle that the pressure is constant (neglecting the change in pressure that occurs with depth) throughout the liquid. However, if I add heat so that this wat... |
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