instruction stringlengths 31 24.3k |
|---|
Please let me share some mathematical finding I stumbled upon, with limited knowledge in physics from high school and by reading Wikipedia:
I wanted to share with you something I stumbled upon about Hilbert spaces and Newton's formula for gravitation.
Newton's formula for gravitation is represented by
$$
F_N(a,b) \cdot... |
I wanted to find Husimi Q function using expression $Q= \langle \alpha|\rho|\alpha \rangle$, where $|\alpha \rangle $ is coherent states of harmonic oscillator. I want to consider system $\rho=|u_n\rangle\langle u_n|$ for infinite square well. I wonder how I could take inner product of $\langle n|u_n \rangle$, where $|... |
In the Maxwell Spring-Dashpot model : Maxwell Material - Wikipedia,
It is assumed that,
$$\sigma_{\text{total}} = \sigma_{\text{dashpot}} = \sigma_{\text{spring}} \text{ ...(1)}$$
$$\epsilon_{\text{total}} = \epsilon_{\text{dashpot}} + \epsilon_{\text{spring}} \text{ ...(2)}$$
Where $\sigma$ stand for stress and $\epsi... |
Is there a notion of rotating an object about its time axis? I'm not sure if this question totally makes sense, but it seems intuitive to me that an object with dimensions in the three spatial directions and the time dimension (so an object paired with an interval of time) could be rotated about the time axis, just as ... |
As we all know that in a pn junction depletion layer is formed and due to immobile charges electric field is directed from n side to p side but why does this electric field acts as a barrier for diffusion rather than an enhancer for diffusion of charge carriers?
|
I am a pre-med interested in nuclear medicine. I recently came upon this wonderous radioisotope called Mo-99 (which decays into Technetium-99m), but in their industry, they measure the quantity of this radioisotope using a convoluted measurement system called a "6-day curie."
If there is anybody in nuclear medicine, ca... |
I’m trying to work out how to set up a spreadsheet to calculate the acceleration and distance needed in order to reach a theoretical top speed for an electric RC car. The speeds we are talking about are an excess of 200 mph. I am able to calculate whether or not the power system will be able to physically move the vehi... |
In the book Modern Physics by Serway/Moses/Moyer (on page 200,chapter Quantum mechanics in one dimension) it is written that (or what i have understood)when there are no forces on a particle solution of schrodinger equation in separable form is identical to that of a plane wave. But the wavefunction associated with a p... |
While we understand the universe to have had a beginning in the big bang theory, if gravity is quantum in nature yet still has an infinite range then surely once the distance between galaxies becomes great enough, pair production will begin in between those galaxies as a result of the gravitational potential energy bei... |
So, I have been told, but not explained, why the two-point function of the stress energy tensor, $\langle T_{zz}(x)T_{zz}(0)\rangle\propto 1/z^4$. I believe it stems from the analysis of field operators at an RG fixed point, but I can not put words to it.
Any help is appreciated.
|
Gravity is non-linear, so if it is mediated by gravitons, gravitons must interact with each other. On the other hand, the effects of gravity moves with the speed of light, so if it is mediated by gravitons, gravitons must be massless.
How can gravitons interact with gravitons if they are not charged under gravity?
|
parsec is defined as the distance at which average radius of earth's orbit around sun would subtend an angle of 1''(second of arc). But suppose im looking at this star when earth is on one side of the sun, now six months later earth is on the other side of the sun and when im looking at this star theres some sort of pa... |
I'm trying to determine the photon emission wavelength ranges for different atoms.
For hydrogen, it's super simple. We use the $$ E_n = -\frac{13.6}{n^2} $$
Then, if we want to see the wavelength of photon emitted from $n=3$ to $n=2$, we do $$E_Δ = E_3 - E_2$$ $$ E_Δ = \frac{hc}{λ}$$ $$ λ = \frac{hc}{E_Δ}$$
I'd like to... |
Is there any way to calculate the mean energy of emitted x-rays in kev if the source have voltage of 140 kV and current is 1.25 mA?
|
I was thinking about the good old question of 'Why do molecules have lower energy than the atoms?'
And in a video (around 6:15), this good old energy graph is shown, which is stated as the 'answer' to the question.
But, I still dont undertand how this graph comes about.
The video showed this for two hydrogen atoms, and... |
In vacuum, it is not possible for an electron to emit a single photon. That can be proved by using 4-momentum.
(Let $ c = 1 $)
Initially,
$$
P_e^{\mu}=\left(E_e, \mathbf{p}_e\right)
$$
Finally,
$$P_e^{\prime \mu}=\left(E^\prime_e, \mathbf{p}_e^{\prime}\right) $$
$$P_\gamma^{\mu}=\left(p_\gamma, \mathbf{p}_\gamma\right... |
I have recently been learning about the quantum harmonic oscillator and how it is described in the language of ladder operators. At the moment the logic behind the number operator seems incomplete to me. As I understand it, the Hamiltonian can easily be shown to be
$$
\hat{H} = \hbar\omega(\hat{a}^\dagger\hat{a} + \fra... |
I studied the experience of Kim et al. (1999) that specialists are familiar with :
https://en.wikipedia.org/wiki/Delayed-choice_quantum_eraser
https://arxiv.org/abs/quant-ph/9903047
I propose here a modification of this experiment and this modification leads me to contradictory theoretical experimental results:
To begi... |
The problem is from the book Classical Mechanics by David Morin. Here's my attempt
One of the principal axes will be along the rod ($\hat x_1$) and other two will be passing through the center perpendicular to each other ($\hat y_1$ and $\hat z_1$). The angular velocity comes out to be $\dot{\theta} \hat x_1+\Omega co... |
I'm trying to find internal energy of ideal gas as function of entrophy and volume. I think I can use this formula some way:
$$
\mathrm{d}U = \left(\frac{\partial U}{\partial S}\right)_V \mathrm{d}S + \left(\frac{\partial U}{\partial V}\right)_S \mathrm{d}V.
$$
I have no idea what to do next. The result should be:
I c... |
I recently read a paper in which Alan Boozer says,
The W7-X stellarator was made quasi-isodynamic rather than
quasi-symmetric in order to minimize the parallel currents as well as
the ripple-trapped diffusion.
Page 2 of a separate article by Jorge and coauthors gives an explanation of the concepts of quasi-symmetric ... |
Let $M$ be a Lorentzian spin $4$ manifold, i.e. admits a spin structure $Spin^+(M)\rightarrow M$, which is just a principal $Spin^+(1,3)$ bundle over $M$, which is compatible with the bundle of oriented, and time oriented, orthonormal frames over $M$, denoted $SO^+(M)$. Furthermore, let $P\rightarrow M$ be a principal... |
Hello I’m a HS student so I apologize if my knowledge isn’t adequate enough, or if you have to dumb down concepts for me.
I’m writing an IB extended essay, and right now I’m trying to understand creeping flow. I think I understand the general gist of it. When the reynolds number is much smaller than one because the ine... |
I am trying to write down the extended BV-action of the free electromagnetic field in a physicist notation, but I don't find it anywhere. I found the following formula in example 3.1. of the paper Remarks on Local Symmetry Invariance in Perturbative Algebraic Quantum Field Theory , by Kasia Rejzner:
\begin{equation}... |
An antipersymmetric matrix is one that is antisymmetric about its anti-diagonal.
The simplest example comes from the Pauli Matrices:
{σ[0],σ[1],σ[2]} are not antipersymmetric
σ[3] is antipersymmetric.
Of course, σ[3] rotates democratically among σ[1] and σ[2]; there surely is no physical distinction here. Even so, i... |
I have been reading about Compton Scattering and got confused about exact technicalities. So forgive me if I ask multiple questions, but all related to each other. This is due to the fact that you don't have to think about how to answer.
From Wikipedia,
Compton scattering is the scattering of a high frequency photon a... |
Table salt can be electrolysed in molten form, water in liquid form etc etc but why can it not be electrolysed in solid form? What is the effect of allotrope
|
I'm an undergrad with an electronics repair background trying to find an explanation for one of the fundamental aspects of a transformer. Every explanation I've found of a transformer's basic operation insists that there is essentially no power loss; that is that VxI in the primary = VxI in the secondary. This suggests... |
Suppose that we have an $n$-dimensional vector space $X$ together with a basis $\{\theta_i\}^n_{i = 1}\in X$.
$$\bigwedge(X) = \mathbb{C}\oplus\bigwedge^1(X)\oplus\bigwedge^2(X)\oplus\cdots\oplus\bigwedge^n(X) = \bigoplus^n_{i = 1}\bigwedge^{i}(X)$$
In which every $z\in \bigwedge(X)$ can be written uniquely as $$z = z_... |
I don't know very much about the theory of light, but since people talk about light as a wave and talk about the wavelengths of light, I'm going to assume that whenever you see any source of visible light, it's meaningful to talk about the waveform of light, i.e. a real-valued (or possibly vector valued) periodic ampli... |
I've read several threads on what exactly a photon is and how it can't be modeled with a wavefunction the same way electrons can. In particular, this answer to my question about whether photons are actually particles says explicitly that what makes photons different is that they're massless, and I read a few other pos... |
No analytical equation of state for the Lennard-Jones substance is known, but, as far as I know, one of the known best approximations is the Kolafa-Nezbeda equation of state (given in equations 30-32).
How do I find the vapor-liquid coexistence pressure as a function of temperature starting from the equation of state? ... |
Short introduction to my understanding:
As far as i understand, virtual particles are usually defined to be the internal lines in Feynman Diagrams. But we know that those are just useful tools to calculate amplitudes in interacting quantum field theories.
In a free theory I have no interactions, hence no internal lines... |
In Eq. (5.7) of his book "Statistical Physics of Fields", M. Kardar proposes the identity
$$
\langle e^{\sum_i a_ix_i} \rangle
=\exp{\left[\sum_{ij}\frac{a_ia_j}{2}\langle x_ix_j \rangle\right]}\tag{5.7}
$$
where the expectation value is taken with respect to a set $\{x_i\}$ of Gaussian distributed variables. I attempt... |
To give background, the $c$-theorem applies to 2D QFT's and the function form is given as $c(g) = C(g) + 4H + 6G$ where $C$, $H$ and $G$ are two point functions of the stress energy tensor.
So, I know how to prove the $c$-theorem very well, but I haven't been able to find any concrete examples of computing the $c$-func... |
When the photon is incident on free electron, we say that compton happens. Though, we require that photon is x-ray or gamma ray. I wonder why at least x-ray is required.
I have my own observation and correct me if I'm wrong. I just want to make sure. Due to the formula of $$ λ_f - λ_i = \frac{h*(1-\cos a)}{mc}$$
We can... |
I have been reading this article about the quantum vacuum state, and in the section that I linked to, there is a video showing an experiment that shows visibly that quantum fluctuations are actually happening (see the video in the link). The quantum fluctuations are visible because they amplified them using Spontaneous... |
I have a question about the behavior of the temporal part of the wavefunction in an infinite well. For reference, the solution given in my textbook for the wavefunction of a particle in an infinite well with 0 potential inside the well is :
$$\phi(t)=e^{{-iEt}/{\hbar}}$$
$$\psi(x)=\sqrt{2/{L}}\sin({n\pi x}/L)$$
The der... |
As an example, why does glass tend to break by means of intergranular fracture?
My analysis so far led me to believe that the tendency can be related to the intermolecular bond strength in a given crystal grain and the intergranular bond strength. A stronger bond means that better load bearing. If the intermolecular bo... |
I'm thinking that the Many worlds interpretation trivializes the Born rule. Suppose we take an electron's spin's state vector such that the probability of spin up is 0.6 and that of spin down is 0.4. We take 100 such identical systems and perform measurements on them one after one.
According to the Many worlds interpre... |
I have cross correlated the CMB map (WMAP 7 Year map) and the large-scale structure tracer- quasar (NBC-KDE Quasar catalog from SDSS-6 avilable here) in real space by following the this paper by Tommaso Giannantonio. I have computed the observed CCF and I need to compare it to the Lambda CDM theoretical prediction CCF ... |
Natural rubber has the highest quoted Poisson's ratio I've seen for a real material, usually given as 0.4999. This obviously makes intuitive sense when you think about the behaviour of rubber, and I've seen it explained several times as being a result of the high ratio between bulk modulus and shear modulus of rubber, ... |
I was watching a video describing a way to deduce Newton's Third law using symmetry considerations.
Consider a system of $N$ particles not acted upon by any external force (isolated system). Suppose the medium in which the system in placed is homogenous.
Now we are displacing each particle in the system simultaneously ... |
Consider a Lorentz force for a positve charge particle q, q>0 (not electrons, not holes, just general case), The lagrangian we can write down is
\begin{equation}
L=\frac{m_0}{2}{\vec{v}}^2+q(\vec{A} \cdot \dot{\vec{{v}}}-\phi)=\frac{m_0}{2}\left(v_x^2+v_y^2+v_z^2\right)+q\left(v_x A_x+v_y A_y+v_z A_z\right)-q \phi
\en... |
The pipe is long, so the moving air never gets to circulate with the outside air. The piston starts off in the middle of the pipe, so it's pushing the air in front of it and pulling the air behind it. There is a high pressure wave moving ahead, and a low pressure wave moving behind both at at Mach 1.0 in opposite dire... |
A small model car is released by my hand and goes down a ramp and hits a wall.
There is no friction or air resistance and the car is influenced by -9.8m/s^2 gravity.
Why does the maximum acceleration (caused by impact) increase when the car's travel distance increases?
I understand that the maximum acceleration occurs ... |
Heres a link to the question im referring to just in case the image is not visible in the post - https://ibb.co/2vsZy90
Can someone please this mark scheme answer in simple terms. Firstly, what exactly is a pulse and how it is different from a normal wave?
Also, what is pulse duration and pulse length, and how exactly... |
At a weight m, a plane is acceleration upwards at rate of a. We also remember the value of g.
From my understanding, we have two opposite forces that we care about.
The force due the gravitational acceleration, which points in the negative y-direction,
The force of the upwards acceleration, which points in the positiv... |
Radius is not a just simple size or length between the two points. The radius shows the connection of linear and angular values. Something must indicate the information about a perpendicularity of the radius to the angular values. This something may be radian at dimension units of radius. So if$$\left[ r \right] = \fra... |
Is there a possible slight difference between protons and electrons behaviour while they are accelerated at speeds that cause relativistic changes to their mass. Why am I asking that? Because for a proton we know that it is made of several components which of them are the three quarks. If they have some speed inside th... |
I am exploring the behavior of the electric field and its implications, and I am trying to understand the behavior of a positively charged rod when it is placed inside a positively charged ring and is displaced by a small amount perpendicular to the axis of the ring. To help illustrate the situation, I have included a... |
I'm reading Brief Answers to the Big Questions by Stephen Hawking. In chapter 4, it discusses whether we can predict the future. As many have known that Laplace put forth that if we knew the positions and speeds of all the particles in the universe, we would be able to calculate their behaviour at any other time in the... |
From Wikipedia, I'm copying two things:
It is the low-energy limit of Compton scattering: the particle's kinetic energy and photon frequency do not change as a result of the scattering.
In the low-energy limit, the electric field of the incident wave (photon) accelerates the charged particle, causing it, in turn, to e... |
I'm studying the possible connection between correlations and thermodynamics work.
In particular, in this article: Wormholes and the thermodynamic arrow of time, I am struggling to find their equation (2.10) i.e
$$
W \leq I * \frac{T_1+T_2}{2}
$$
The extractable work is bounded by the mutual information times the mean ... |
It is known that in a compact manifold of dimension $d=4$, the following integral is invariant under small deformations of the metric tensor
$$
\int_\mathcal M \sqrt{g}(R^2-4R_{\mu\nu}R^{\mu\nu}+R_{\mu\nu\rho\sigma}R^{\mu\nu\rho\sigma})
$$
As a matter of fact, a theorem tells us that this computes the Euler characteris... |
After studying electric field variation inside a non-conducting ball with cavity, I wished to calculate the potential of some points to compare. For simplicity, I made this diagram
And want to calculate the potential at point O (centre of ball) and B (centre of cavity)
Now as my teacher told me, I have to subtract the... |
I have viewed the definitions of the Hubble Sphere and related cosmological concepts, as well as various explanations, yet Im still struggling to comprehend a full visualisation of this, which I would prefer instead of taking its word for it. To phrase the question that would most help me, the following follows: so fro... |
I know that we call a quantity a vector if it has magnitude and direction and follows vector laws of addition(the triangle law and parallelogram law). But why only it should only follow addition laws and not other laws like cross product or dot product and why they are not given in its definition.
Is it like that if a ... |
Say we had an object at height $h$ in a gravitational field, and of mass $m$, its GPE would equal $mgh$, now say we dropped it and it fell a distance of $h$, the work done on the object would be equal to $mgh$, as $W = Fx$, and $F = mg$ and $x = h$, so why is the objects energy not now $2mgh$, but rather $0$?
|
How do I find $<x|p|\psi>$ in terms of $\psi (x) = <x|\psi>$
And again for $<x|H|\psi>$, where $H$ is the hamiltonian?
|
Generally speaking the density operator for discrete states $|\psi_i\rangle$ is given by:
$$\rho = \sum_i p_i|\psi_i\rangle\langle\psi_i|$$
I had a hard time finding this (it is not even on wiki) but for a continuous basis {$|x\rangle$} this goes over to:
$$\begin{array}\rho = \int_{-\infty}^{+\infty} p(x)|x\rangle\lan... |
How can I show that the Liouvillian superoperator $\mathcal{L}$ satisfies
$$
\langle A,\mathcal{L}B\rangle=\langle \mathcal{L}^\dagger A,B\rangle
$$
where $\langle A,B\rangle =\mathrm{Tr}(A^\dagger B)$ is the Hilber-Schmidt product, and $A$ and $B$ are two operators.
In other words, how can I prove that
$$
\mathrm{Tr}... |
I was reading about EUV and the extraordinary process of firing two different lasers as tin droplet to collect 13.5nm wavelength light and I was wondering why this is required and we can't just create that light directly?
It would be helpful to understand what determines the wavelength of a laser and additionally why i... |
This question is related to the question:
"how-to-measure-the-strength-of-a-prescription-eyeglass-lens"
That was asked in the following link:
https://rb.gy/lgp99
Han-Kwang Nienhuys explained how to find the optical power of a positive lens:
For a positive lens:focus sunlight (for safety, preferably on dark, inflammable... |
If we let $\hat{\rho}$ be the density matrix of a Bell state. I have seen that calculating the trace,
$$
Tr(\hat{A} \otimes \hat{I} \hat{\rho}) = Tr_{\mathcal{H}_A}(\hat{A}\hat{\rho}_{\mathcal{H}_A})
$$
Where $Tr_{\mathcal{H}_A}$ is the partial trace in the Hilbert space $\mathcal{H}_A$ and $\hat{\rho}_{\mathcal{H}_A}$... |
I'm learning about the transport of electrons in solids (especially based on the Drude model), and I was wondering how the different scattering processes that take place in metals vary with temperature.
Speciffically, I would like to know what scattering processes are dominant in $\rm Au$ and in an alloy such as $\rm A... |
I had read some crazy theories about the speed of light.
I am going to explain my own understanding of "speed" to make my point.
Suppose there was an object we'll call A exists at position P1 in time T1. This object is to move 1 position at a time; so at time T2, A is in the next position P2; at time T3, it's in positi... |
I understand that electrons bound to atoms can only absorb energy in discrete multiple quantities and I've seen the derivation the wavefunction for an electron in a box and how the principle quantum number shows up as a result of applying boundary conditions to the Schrödinger equation, so I feel like I understand the ... |
The volume in the 6D phase space available to photons whose frequency in the range between υ and υ+dυ is $$\frac{4\pi Vh³υ²dυ}{c³}$$ Why when taking into account the polarization of photons, this doubles the available volume to $\frac{8\pi Vh³υ²dυ}{c³}$?
|
At the beginning of chapter 4 of the book "Anomalies in quantum field theory" Reinhold Bertlmann, on page 178, the book says:
symmetries: conservation laws are connected with symmetries, which is the basic statement of the Noether theorem. Let us consider now as gauge fields a vector field and an axial field which we ... |
Suppose I have a Cat state $|C_{\alpha}^{+}\rangle = | + \alpha\rangle + | - \alpha\rangle $. Is there a set of bosonic gate operations i.e. rotation, displacement, SNAP gate etc. (in phase space) that can map it to $|C_{\alpha}^{-}\rangle = |+ \alpha\rangle - |- \alpha\rangle$?
|
In the image above, we have the principle of induction cooking. An alternating current is run through the coil, which causes a change in flux. This change in flux induces eddy currents in the conductive pan, and by Joule heating/resistive heating (P=VI), this causes the pan to heat up.
So the only thing that you need... |
My question uses the PN junction simply as a concrete example of band bending establishing thermal equilibrium. Below I state my question first and then provide an overview of my current understanding of the situation to try to clarify the question and provide context.
My question:
The band diagram for a material depic... |
To answer this question, shouldn't we include the masses of the neutrons and the electrons in the given nuclear reaction? If I do that, I obviously get a slightly different answer from the one published. (Difference of about 4%). Why haven't they included masses of the neutrons and the electrons in their answer?
Also,... |
What I mean is how the shape of an object affects it's physical properties.
I've been studying Marine Biology and there's constant talk of how a fish's shape determines how well it can swim but no explanation of why, say, "Stream lining" reduces water resistance outside of it "just making sense" and I'd like something ... |
On a problem, I'm working on calculating the electromagnetic force in the absence of charge distribution with Maxwell's Electric Stress Tensor.
$F=\int d^3r \nabla\cdot \stackrel{\leftrightarrow}{T}=\int d\vec{S}\cdot\stackrel{\leftrightarrow}{T}$
Where
$T_{ij}=\epsilon_0(E_iE_j-\frac{1}{2}\delta_{ij}E^2)$
Or in terms ... |
One problem of electric vehicles is that the battery capacity often shrinks under low temperatures. Some batteries can lose as much as 50% of capacity in winter.
What I don’t quite understand is how the capacity shrinks. Does the low temperature prevent the batteries from being fully charged or fully discharged or both... |
I know how to solve the Schrodinger equation for an infinite well where I set the well to be to 0 potential between x = 0 and L and infinite potential outside these regions. I am curious whether you could solve the equation if I set the well from something like x between 0.3 to 0.8 or similar asymmetric situation. I t... |
In recent years several ultra high energy cosmic ray events are observed on Earth. These particles carry energies way beyond even the most powerful particle accelerators we can realistically build. They are likely created from extremely high energy particle collisions near black holes or neutron stars. However, not all... |
The Schwinger–Dyson equation on Peskin and Schroder reads (p.308):
$$
\!\!\!\!\!\!\!\!\left\langle\left(\frac{\delta}{\delta\phi(x)}\int d^4x'\mathcal L\right)\phi(x_1)...\phi(x_n)\right\rangle = \sum_{i=1}^n \left\langle\phi(x_1)...(i\delta(x-x_i))...\phi(x_n)\right\rangle \tag{9.88}
$$
This equation tells us that the... |
If the electric field inside an infinitely long charged cylinder is non-zero except origin, how can be the inward flux zero?
https://www.youtube.com/watch?v=BF3wEV4tWq8
If we look at this video, we would see that a charged ring has a non-zero E-field inside it except for the origin. A cylinder can be constructed by inf... |
I have a question in Peskin and Schroeder's book (Quantum field theory) page 46. Why
$$\big[ \sqrt{E+p^3}(\frac{1-\sigma^3}{2})+\sqrt{E-p^3}(\frac{1+\sigma^3}{2})\Big]=\sqrt{p.\sigma}~?$$
and why $$(p\cdot \sigma )(p\cdot \bar{\sigma})=p^2~?$$
I don't understand the meaning of $\sqrt{p\cdot \sigma}$. I'd really appreci... |
On page 661 Peskin and Schroeder calculates the ABJ anomaly pertubatively. The book gives the ABJ anomly as
$$\tag{19.45}\partial_\mu j^{\mu 5}=-\frac{e^2}{16\pi^2}\epsilon^{\alpha\beta\mu\nu}F_{\alpha\beta}F_{\mu\nu}.$$
However when the book goes on to check (19.45), it only checks on page 664
$$\tag{19.60} \langle p,... |
Consider two isolated $\rm H$ atoms. They can be in different spin states, but the different states are degenerate. Now move these $\rm H$ atoms together. Now the singlet state will become energetically more favorable than the triplet state, and lead to the bonding interaction with one up one down electron.
But what ha... |
classical electromagnetism , from my understanding can be derived completely from coloumb's law , charge invariance, superposition principle and postulates of special relativity. Biot savart law and lorentz force law are all consequences of it . For derieving faraday's we need not do any experim... |
I recently solved a question which asked me to find the charge inside a cube of length $a$ placed in an electric field $\vec{E} = C x \hat{i}$.
Using Gauss law, I found the answer to be $C \epsilon_0 a^3$, irrespective of where the cube is placed.
I wonder how such a uniform charge density will create such an inhomogen... |
I remember hearing at some point that pertubation QFT using Feynman diagrams can be thought of as certain limits of lattice QFT. Is there a precise statement of this fact? Or is it just a heuristic with no mathematical formulation/justification?
Alternatively, is there a way to do calculation on lattices, that gives th... |
The complex exponential ansatz for electromagnetic waves is utilized for algebraic simplicity. However, we admit that, depending on the setup for the ansatz, only the real or imaginary part is of physical concern. In various scenarios, e.g. total internal reflection, the Maxwell equations in (linear, homogeneous) media... |
There is literature on the lie symmetries of quantum harmonic oscillator differential equation. The generators satisfy certain lie algebra.
On the other hand, we have ladder operator method. The relevant operators satisfy some lie algebra.
I was interested in knowing if there might be some connection with the two appro... |
A non-spontaneous change occurs when an external effort is being done to it. Since the external effort is also a natural source , does this mean that there is no truly any non-spontaneous process in nature (universe) ?
Example to illustrate my point :
An electrochemical process (like in a galvanic cell) can be reversed... |
i would like to evaluate $$\int\mathcal{D}x\ e^{-\int\limits_{-\infty}^{\infty} dt\ (\dot x+\alpha x)^2}\tag{1}$$
and it is my understanding that the way to do so is using the saddle point approximation, however I'm new to using it and am unsure how to do so for the case of an action
i was able to solve the Euler Lagra... |
I was playing around a physics simulation and I saw this.
(One of my first questions , forgive if this question is too simple or has grammatical errors)
Here it is in action.
I wanted to figure out its time period as it is periodic motion, i also figured that they are performing rotation along the joints and I can us... |
I did a Curie-Weiss fit to my ferromagnetic data and found a Curie-Weiss parameter $\Theta_{CW}$ lower than the Curie temperature $T_C$. My question is, I would expect that the Curie-Weiss parameter is larger because it gives us information about the molecular field, in which case it is always larger than the Curie Tem... |
I wanted to ask if I can use this law $P=\rho gh$
to compare between the pressure of two solid irregular cylinders (they don't have the same area above and at the bottom) but they do have the same area at the bottom
And also if I can use it to compare the pressure of one same liquid in two irregular cylinders (don't ha... |
I'm looking for an undergraduate textbook that covers classical mechanics with all the standard subtopics and applications (conservations laws, gravity, Hookean springs, friction, and similar), but approaching them from a point of view and notions that are closer to relativity theory (special and general). I do not mea... |
My lecturer has stated that the principal axes of the moment of inertia (hereafter MOI) are a set of axes such that the off-diagonal deviation terms of the MOI tensor disappear. He then said that in these axes, the mass distribution on either side of each coordinate plane will be the same.
I'm misunderstanding under wh... |
Maybe dumb question, not sure, but I would need some help here to understand.
https://theglobestalk.com/james-webb-telescope-see-back-in-time/
So according to physics we can look back in time probably close to the time of big bang with James Webb telescope since light that arrives here from ~14 billion years ago will ... |
I am bit bothered by the "definition" of Tegmark's level IV multiverse. I have read that it is a "collection of all mathematical models" (whatever that means). I have also read that in this multiverse "all possible mathematical structures have a physical existence."
Can anyone makes some sense out of this, or precisely... |
My question is about how to detect ghostly degrees of freedom at the level of equations of motion. It is not clear for me how does this work. Let me explain with an example:
Consider the following Lagrangian density for a vector field (I use mostly minus convention):
$$
\mathcal{L}_{kin}= -\frac{1}{2}\partial_aA_b \par... |
Let's consider a free Wess-Zumino Lagrangian given by
$$\mathcal{L} = \partial^{\mu}\overline{\phi}\partial_{\mu}\phi + i\psi^{\dagger}\overline{\sigma}^{\mu}\partial_{\mu}\psi\tag{1}$$
Whose supersymmetry transformations are
$$\delta\phi = \epsilon\psi, \space \delta\overline{\phi} = \epsilon^{\dagger}\psi^{\dagger}, ... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.