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Why does the unit vector in polar coordinates change with time when an objects position is changed?
|
My understanding is that when it comes to the correspondence between representation theory and particle physics, every irreducible representation of the Poincare group has a corresponding fundamental particle.
My questions are as follows:
are all of the currently known fundamental particles predicted to
exist by thi... |
Why does cutoff voltage in photoelectric graph remain same regardless of change of intensity and frequency of light I understand in intensity that minimum voltage required to kick off slowest electron is constant as intensity is not related to energy of phtoelectron but cannot understand in case of frequency. I have at... |
I am doing a course on Lagrangian mechanics and the instructor mentioned that the numerical value of the Lagrangian is conserved when I shift between two inertial reference frames, even though their functional forms might be different. He then mentioned that this is unlike what happens with the Hamiltonian.
I am havin... |
In CGS: I know that:
$$
U_E = \frac12\sum_{i=1}^Nq_i\sum_{j\neq i}\frac{q_j}{|\mathbf{r}_i-\mathbf{r}_j|}.
$$
In the continuous. Is it correct this conclussion?
$$
U_E=\frac12\int \rho(\mathbf{r})\varphi(\mathbf{r})d^3\mathbf{r}.
$$
I know that this is not always true, because for just a lonely charge $q$ the energy is... |
We know that divergence of Electrostatic field is
$$ \overrightarrow{\nabla}\cdot\overrightarrow{E}=\dfrac{\rho(\overrightarrow{r})}{\epsilon_0} $$
in case of a point charge, the divergence would be the Dirac-delta function.
What, similarly could be said about the curl at the location of point charge, we know that ... |
There are some papers such as https://arxiv.org/abs/quant-ph/0008040 and https://arxiv.org/abs/1907.09832 that discuss going from qubit to the continuous model. But I'm curious if there is a way to go from the continuous variable model to the qubit model?
|
Is there an experimental system, or such that can be observed in nature where a particle's wave function assumes a form - $\psi(x)\propto \frac{1}{\sqrt{x^2+1}}$ such that $|\psi(x)|^2$ is Lorentzian?
An answer to this question Is there a condition of quantum mechanics that forbids Lorentzian distributions? claims that... |
I have come upon this question that asks me to estimate the contribution of an expansion in a liquid to its heat capacity. However, I do not understand how a change in its volume can affect it's heat capacity.
Furthermore, after thinking about it for some time and then looking at the solution I have become more confus... |
For a continuum model of non-interacting spinful fermions with many-body Hamiltonian
$\hat{\mathcal{H}}=\int_{\mathbb{R_2}}d\vec{k}\begin{pmatrix} \hat{c}^{\dagger}_{\vec{k}\uparrow} & \hat{c}^{\dagger}_{\vec{k}\downarrow} \end{pmatrix}H(\vec{k})\left(
\begin{array}{c}
\hat{c}_{\vec{k}\uparrow}\\
\hat{c}_{\vec{k}\down... |
In the Chapter 8 of Coleman's many-body physics book, he argues as follows. In the impurity problem, the approximate self-energy can be written as (8.89). I have no problem until this part. However, I cannot understand the yellow-marked part. More specifically,
(1) Why can we consider only near the Fermi surface in qu... |
Depending on the literature, we see for the electroweak scale the following typical values :
100 GeV, 125 GeV (Higgs mass), 246 GeV (vev), 1 TeV
So what is really the value of electroweak scale?
|
I was reading this paper, at the bottom of the first page, it mentions "It is easy to show that measurement with any number of outcomes can be performed as a sequence of measurements with two outcomes." How can it be possible? Would really appreciate a mathematical explanation.
Edit: I am familiar with the concepts of ... |
please I need clarification about the first principle of thermodynamics, it's general statement is:
$$\Delta U + \Delta \text{KE} + \Delta \text{PE}= W + Q .$$
Supposing that: $ΔU = 0$ and $Q = 0$, then:
$\Delta \text{KE} + \Delta \text{PE}= W$ (of total forces).
But, We know from classical mechanics that :$\Delta \t... |
I'm solving for a particle moving in the Morse's potential
$$
H=\frac{p^2}{2m}+A\left( e^{-2\alpha x}-2e^{-\alpha x}\right)
$$
Now, considering an operator $B=-\partial_x +C e^{-\alpha x}-D$ and its hermitian conjugate $B^{\dagger}$; I have to find the values of $C$ and $D$ which make the Hamiltonian look like
$$ H=B^{... |
I am looking for a qualitative explanation, if possible, of the following passage from Peskin & Schroeder, bottom of page 26, concerning the quantised real Klein-Gordon field:
A positive frequency solution of the field equation has as its coefficient the operator that destroys a particle in that single particle wavefu... |
I usually use terms like 'radiowave', 'microwave', 'X-ray', etc. to refer to ranges of electromagnetic (EM) frequencies ($f=2\pi/\omega$) or wavelengths ($\lambda = 2\pi/k$) in air or in a vacuum, where the speed of propagation is approximately the same as the speed of light in vacuum ($v\approx c$) and the dispersion ... |
I am trying to teach myself Electrodynamics through self-study of Griffiths' Introduction to Electrodynamics, and I am having difficulty with a calculation that involves a line integral of a point charge. I posted this question to Math Stack Exchange yesterday, but I was unable to get an answer. I'm not really sure th... |
I am just reading some material about symmetry breaking and so-called effective action/potential
Consider a lagrangian
\begin{equation*}
\mathcal{L}=\frac{1}{2}(\partial \phi)^2-\frac{1}{2}m^2\phi^2-\frac{\lambda}{4!}\phi^4=\frac{1}{2}(\partial \phi)^2-V(\phi)
\end{equation*}
Now it is known for $m^2>0$, symmetry is u... |
I read that mirrors absorb only a small amount of light(1-2%). And recently MIT engineers developed the "Blackest Black"(blacker than Vantablack) which reflects only 0.005% of the light. Let's say we create a perfectly reflective mirror which absorbs 0% of the light and a Black object which reflects 0% of the light. If... |
My question is how to average the color factors when calculating the magnitude of amplitude for gluon-quark scattering process, for example, how to average over color factor for $|\mathcal{M}_{a}|^{2}$. I have trouble in this exercise. But for quark-quark scattering or quark-antiquark scattering, I have known how to av... |
Suppose we have a conductor of length $L$ and uniform cross-sectional area $A$. Let us apply a potential difference $V$ between the ends of the conductor. Then the electric field inside the conductor is
|
As the temperature increases, the resistivity of conductor also increases why?
|
I am wondering why the Hall coefficient for Al is negative, I am thinking about holes (I understand how holes word in semiconductors, but I can not use that because metals have no bandgap...), but I don't find any information about holes in metals, why is that coefficient negative? And how can I interpret that?
|
Centripetal force is directed towards the center, then why does an object placed on a rotating disc move outwards?
On the other hand, when a particle is placed in a cylindrical container containing water that rotates, the particle moves towards the center.
Why does this happen?
|
given a rigid body $K$, I always had seen the formula
\begin{equation}
I_{ij} = \int_K[\mathbf{x}^2\delta_{ij} - x_ix_j]\rho(\mathbf{x})\mathrm{d}^3\mathbf{x}
\end{equation}
for the inertia tensor. But in my derivation this seems to be correct only in cartesian coordinates (where $g_{ij} = \delta_{ij}$).
Here are my s... |
Consider a hollow metallic spherical shell given a charge Q. The entire charge must reside on the outer surface of the hollow sphere. Now consider a Gaussian surface on the outer surface of the sphere. By spatial symmetry the field at every point on the surface
is the same , let it be ‘E’.
The flux through the entire s... |
I have problem because I don’t understand the difference between CLR RLC and LCR, they are the same no ? They have the same composant just placed in different ways, I did already found the Transfer function of RLC function but I just to know first in what there is a difference with these 3 circuit and if yes how should... |
Today I saw a rainbow after almost a decade. I live in Noida (a city) in India. Most people I know believe that: we don't see rainbows nowadays because of pollution and now after nearly 3 months since the COVID lock-down, the pollution must have come down and the rainbow was visible. Is this belief true?
You can see ne... |
The EM free field can be written with the Hamiltonian formalism as:
$$H=\sum_\lambda\frac 1 2(P_\lambda^2+\omega^2 Q_\lambda^2)$$
In this expression $Q_\lambda$ and $P_\lambda$ are canonical variables.
I've seen that a transformation of the system that transform the variables $Q_\lambda'=Q_\lambda+\delta Q_\lambda$, $P... |
I've come across this funny identity involving the Riemann tensor, which I'm not really sure how to even start proving.
$$ \nabla_k \nabla_i R^{ik}_{ \ \ \ mn} = 0 $$
The issue in attempting to use normal coordinates here is that this is still a third order derivative equation in the metric, I've tried expanding but i... |
I was looking at my special relativity notes and when covering EM, I was wondering if the following is true?
Namely, given the four-potential $A_{\mu}$, by definition it is that: $F_{\mu \nu} = -A_{\mu,\nu} + A_{\nu,\mu}$.
Q: I am wondering if it is also that $A_{\mu,\nu} + A_{\nu,\mu} = 0$?
|
Please consider the following RC circuit as context:
Assume that the circuit has been connected for a long time. If switch S has been opened at $t=0,$ the differential equation used to solve for the charge on the capacitor $Q$ would be, by using Kirchhoff's loop rule:
$$\frac{Q}{C}-R\frac{dQ}{dt}=0, \quad Q(0)=C\mathc... |
While solving some simple capacitor problems, I found that certain "excess" capacitors could be removed from a circuit if they're connected across equipotential wires (especially in case of symmetrical circuits), with the logic that no current flows through equipotential surfaces.
WHY?
One of my friends asked me to c... |
I can't seem to understand why water in the bottle wont drop down until the water level equalizes so pressure is same in any horizontal plane. As you can see just at tip of bottle,the pressure inside bottle would be higher due to the water level above it
And yes the bottle is closed from the top, so I assume the answe... |
My dad bought an earthen pot and he kept it on our glass table. Worried that the glass could break on filling the pot with water. I kept a metal plate beneath it. At first, it seemed like a good idea , but on further thinking I was unsure if it would actually help in bringing down the pressure on the glass. what if I p... |
The question I have is, what conditions must satisfy an external force dependent on velocity so it can be a part of the lagrangian and Euler-Lagrange equations are still true.
|
I've read multiple papers (e.g. https://journals.aps.org/prb/abstract/10.1103/PhysRevB.79.144108) on the multiscale entanglement renormalization ansatz (MERA) where algorithms are given for how to optimize a MERA tensor network to minimize the energy of a given Hamiltonian. I'm wondering whether a systematic approach e... |
We know that the rate of radiation is proportional to the surface area offthe emitting body. However, this is true for an opaque body.
When considering a transparent body, will the radiation still be proportional to the surface area? Or, will it be proportional to the volume of the body which seems more likely to me?
(... |
The observation is that the perturbative spectrum of $\mathcal{N}$=8 supergravity in four dimensions is exactly the same as the type IIB closed superstring spectrum after dimensional reduction on $T^{6}$ wich is in turn equivalent to M-theory compactified on $T^{7}$ (after a T-duality on an internal direction is perfor... |
I've been studying different scattering processes (from Mandl & Shaw QFT's book, chapter 8) and there's always a purely-mathematical common step I do not understand: the showing-up of the trace. Let me give two specific examples.
$$A_{(l) \alpha \beta}=\sum_{s_1} \sum_{s_2} \Big[ \bar u_{s_2} (\vec p_2') \gamma_{\alpha... |
The doubt arises as space translations can be associated to homogeneity of space, time translations to homogeneity of time and classical rotations to isotropy of space. These properties of space leads to conservation laws of energy, total momentum and angular momentum for isolated systems, but there isn't an analogue p... |
I just watched this lecture on rainbows https://www.youtube.com/watch?v=iKUSWJWMSk4 and in it I found out that the colors in the rainbow are not monochromatic. At any point in a rainbow there is a peak light frequency, but all the lower frequencies are also present. So the red side of the rainbow is nearly monochromati... |
Dear physics stack exchange,
I was looking over the darker non-mainstream physics wing of youtube when I came across a video with a person who gave a simple experiment to prove you could accelerate an electron to go faster than the speed of light. If you follow the link your see his apparatus and the key idea here bei... |
I am a bit confused about the idea of spontaneously symmetry breaking (SSB), from the point of view of QM. I am talking here about the energy plot looking like a mexican hat in 2D (not the general Higgs one in the complex plane). I am mostly thinking of it by making an analogy with the ammonia molecule problem. The 2 l... |
As per the title. I'm probably thinking too naively in a classical way, but intuitively it seems to me that:
the presence of vacuum energy at fixed density throughout all space and,
an expanding universe
would imply that more and more energy is constantly added to the universe.
I am assuming we have not given up on e... |
I read the similar topics here and on the web, but non of those seem to help me. I know that the instantaneous axis of zero velocity lies on the xy plan, but I don't understand why it lies on the y axis?
|
I will be taking an oral exam, where I have to do some "airport physics", fast and easy magnitude estimations.
Currently I try to come up with a good way to find the Bohr radius of the hydrogen atom for this exam. Usually one would solve the differential equation by splitting the Hamiltonian in radial and angular momen... |
I have started with kinematics and I have a really basic question of following sign convention i.e taking up and right positive and down and left negative. Is such a convention necessary when I can simply taking a velocity or acceleration as positive or negative depending on if it moves with the body or against it?
Als... |
On the following question Derivation of Maxwell's equations from field tensor lagrangian
We try to calculate the equation of motion of $(1)$ where $F^{\mu\nu} = \partial^\mu A^\nu - \partial^\nu A^\mu$:
$$\mathcal{L} = -\frac{1}{4} F_{\mu\nu}F^{\mu\nu} = -\frac{1}{2} (\partial_\mu A_\nu) F^{\mu\nu}\tag{1}$$
It is said ... |
I have several thermal mugs, two of them by the same brand, have the same look, shape and size except that one is in steel (inside and outside) and the other one, plastic. Both have an insulating layer of air or vacuum.
I do not need a thermometer to tell me that the steel one is much better at keeping liquids cool/hot... |
I just want to know that how spray nozzle turns liquid in small droplets. This thing does not only happens with spray it also happens with perfume bottle or when you squeeze a very high pressure pipe. If you know the answer to it then please share it with me.
|
A projectile moving through two spatial dimensions has a resolution of two velocities, $$\vec i(V_{0}\cos\theta)+\vec j(V_0\sin\theta -gt)$$ each of which should have their own air drag(?) But also orthogonal to each other, just as the velocoties are. Is it correct to sum the two air perpendicular air drags as:
$$\su... |
I’ve already posted this question on the Astronomy stackexchange, but now I see I can post it here too (since there is a tag cosmology and the community is larger here). If this isn’t allowed, please remove. Sorry then!
We know there is a discrepancy between the results for $H_0$. On one side there is the method of the... |
I'm taking a class on classical fields and I came across a statement that I can't think about an argument to show that its true.
It says that Invariance of a Lagrangian under transformations on Poincaré group ensures
the covariance of the Euler–Lagrange equations under these transformations.
How can one prove this?
|
I enjoy the occasional hot drink, but place it below a small fan in order to cool it to a drinkable temperature. Unfortunately, as expected, I commonly forget about my drink, and it ends up very cold.
In fact, it ends up so cold that it feels much colder than I would expect given my relatively warm room ($\sim \mathrm{... |
In physical chemistry book (Thomas Engel, Philip Reid and Robert G Mortimer), the Boltzmann distribution is derived based on the argument that for large system, the dominant energy configuration is similar to the average energy configuration (Example of 4 Harmonic Oscillators of a macrostate E=4h$\nu$). I'm convinced b... |
Ok, I've read this answer:
Why does holding something up cost energy while no work is being done?
But more questions pop up. If there is no work being done does that mean that there is also no power needed to hold object at same height?
P=A/t
If I had a rolling shutters:
Simplified by this model:
What would be the p... |
It isn't clear to me why an 't Hooft anomaly implies spontaneous symmetry breaking. I would like to see an argument which shows this.
The most I can say about this scenario is that if the symmetry is spontaneously broken, then the ground state transforms non-trivially under said symmetry. This creates problems when tr... |
How strange are the ways for finding questions! I was searching for some information on the topic of topological quantum field theory (a question was asked in this context), which directed me to the subjects of d-forms and symplectic geometry, via which I went further to the van der Pol oscillator and chaotic behavior,... |
Consider a particle of mass $M$ moving alongside a segment of length $a$.
Wavefunction:
$$\psi_n(x)=\sqrt\frac{2}{a} \sin(\frac{n\pi}{a}x)$$
Energy:
$$E_n=\frac{\hbar^2\pi^2 n^2}{2Ma^2}$$
Time-dependent perturbation:
$$\varepsilon(t)=\varepsilon_0e^{-\frac{t}{\tau}}.$$
Particle is in a ground state $n = 1$. What is the... |
To be clear about what I mean with "sensorial experiences", let's take for example our visual experiences. Certainly, physics (and other sciences) explains a whole process which involves light arriving to our eyes, a transformation into electric signals that go into out brain, where it is further processed and then, ki... |
A roller of radius 10cm is spinning with a angular velocity of 15 rad/s. It has a completely inelastic collision with a hunk of clay, with mass m moving at 3m/s at it's very bottom edge. Does the angular velocity of the roller (now with stuck clay) increase, decrease or stay the same? (The picture should clarify)
I th... |
I am having some problems finding an explanation why long sound wavelengths travel around objects easier than short ones, hence making lower frequencies audible across longer distances. Most online sources use a slit/opening for the explanation of diffraction but somehow I still fail to grasp what happens to air molecu... |
This question remind me of a doubt on the relation between colors and frequencies.
When we talk about a monochromatic color of a given frequency (or at least a narrow range of frequencies), it means only a generic plane wave with a narrow range of $k$:
$f(k(x - ct))$ where $\omega = kc$.
Or is this type of wave suppose... |
Question:
A parallel light beam of radiation intensity $I$ is incident on a solid right circular cone of height $H$ and radius $R$ as shown in figure. Calculate the net force experienced by the cone if, surface of cone is perfectly
absorbing
reflecting
As for an absorbing surface,
$$p = \frac Uc \Rightarrow F = \f... |
When a current is established in a wire,the free electrons drift in the direction opposite to the current.does the free electrons in the wire continuously decrease?
|
I am currently studying Diode Lasers and Photonic Integrated Circuits, second edition, by Coldren, Corzine, and Mashanovitch. Appendix A.1.1.1 says the following:
In quantum mechanics, measurements are limited in accuracy by the uncertainty principle, $\Delta x \Delta p_x \ge \hbar/2$, where $p_x$ is the momentum in t... |
A Faraday cage blocks electromagnetic fields, provided they are not intense enough to change the state to something non-conductive (e.g. slicing it in two with a laser).
Is there any analogous system that blocks non-local quantum effects, including tunneling?
I have only a layperson's knowledge of quantum mechanics. If... |
In condensed matter physics, Bloch theorem is very helpful in describing the band-structure of periodic systems as it breaks down the wavefunction into a plane-wave part and a periodic potential part. However, I noticed that there are two different ways to write down Bloch theorem:
$\Psi_k (\vec{r}) = \exp(i\vec{k}\cd... |
Since Millikan it is obvious that the charge of the electron can be measured as a result of the force exerted by an external electric field. What we get in detail is the charge from the excess of electrons in a water or oil droplet.
I wonder why we are so convinced that a free electron does not lose part of its charge ... |
I was going through the following paper The 1D Ising model and the topological phase of the Kitaev chain. They call ising spins to be bosonic. If I the quote the paper:
Hard-core bosons realized through spin-flip operators acting on a Hilbert space with spin $s=\frac{1}{2}$.
I do not understand why they are calling I... |
If you live in a two-dimensional world, would it be possible to explain the angular momentum?
|
Recently I was going through a book on magnetism and it said that " If a moving charged particle enters into a region of uniform magnetic field from
outside, it does not complete a circular path".My views about this statement is that it is wrong.Is this statement correct in case of uniform but non constant magnetic fie... |
Where this minus disappear, please?
Source: https://en.wikipedia.org/wiki/Induction_equation
|
I read the book Statistical Methods in Quantum Optics 1 (Master equations and Fokker-Planck equations), published by springer.
In Chapter $5$, to do scale expansion, the writer introduces a system-size parameter $\Omega$. $x$ is a parameter in microscopic unit related to state of the system, for example, the photon num... |
I would like to ask your help to calculate the temperature drop of a fluid (at a specific conductivity) that flows in a silicone tube at different rates. This is a real case and I expect to perform empirical tests to determine the temperature from a point where temperature is known to a second point where I need to cal... |
I do not understand how a black body emits electromagnetic radiation. I assume that heating a black body creates moving charges which induce a magnetic field. But where is the $E$ field part of the electromagnetic radiation coming from? For the $B$ Field to induce an electric field it would have to vary in strength? It... |
A free electron is located in the electromagnetic field of a laser with a given wavelength and intensity.
Is it possible to calculate the amplitude and frequency of the magnetic force that is acting on the electron?
|
Is there a way to find out if a set of electrical components within a given circuit are in parallel/series just by looking at the circuit diagram. If so, can someone give the rules to do this?
|
The gamma matrices obeying the Clifford algebra can be represented by Pauli matrices in (1+1) and in (1+2) dimensions. But is it possible to define a $\gamma_5$ in these dimensions? In the sense of an analogous way of how $\gamma_5=i \gamma_0\gamma_1\gamma_2\gamma_3$ is defined in 4D.
|
I'm currently learning Quantum Mechanics from online video lectures and resources. In most of the web articles and videos, the wave functions are shown as circular waves $e^{i\omega t}$ instead of planar waves $\sin{\omega t}$.
[Note: I'm considering a fixed position and hence the equation $e^{i(k\cdot r + \omega t)}$ ... |
I have difficulties to understand how to solve the Maxwell equations on curved spacetime. I want to solve the equations in the weak regime $g_{\mu\nu}=\eta_{\mu\nu}+h{\mu\nu},~ h_{\mu\nu}\ll 1$ without sources $J_{\mu}=0$. I use $\eta_{\mu\nu}=\text{diag}(1,-1,-1,-1)$.
The Maxwell equations in curved spacetime are:
$F^... |
At this page enter link description here
I found this solved problem " The $x$- and $y$-coordinates of a particle moving on the $xy$-plane at time ttt are given by the following equations:
$x(t) = 2t - 5$
$y(t) = -t^2 + 4t - 1$
My question is that is there a way to make these two functions of positions to be one functi... |
Disclaimer: I present a question which is homework-like, However it is simply to demonstrate an example. I only wish to clarify one thing, that is the validity of the IAR in determining the accelerations.
IAR: stands for the Instantaneous Axis of Rotation
Consider a Massless rod (initially vertical) with two Balls A an... |
I was studying about the cosmological perturbation theory and came across this:
""Being symmetric, the two perturbed tensors contain ten
degrees of freedom each, describing different aspects of gravity.""
Can someone explain what this means in simple terms?
|
I am wondering that it is the right interpretation to interpret $E=mc^2$ with potential energy.
What I mean is this: When I studied nuclear fusion, there was missing mass. The hydrogen's nuclear fusion happens when four hydrogen nucleus fuse into one helium nucleus.
The hydrogen is one proton and the helium is two pr... |
A) a syringe is filled with 10mL water.
The diameter of the barrel of the syringe is 15.9 mm and the diameter of the tip is 1.2mm. With how much force do we need to push on the plunger to empty the syringe from water in 10 seconds? Neglect friction of the plunger and the waters viscosity.
B)Now we add a needle to the s... |
When I read some papers I don't know why exponentially decay of single particle Green's function (in real space) implies existence of single particle gap? e.g., as mentioned at bottom of page 3 in PRL 115, 156402.Is this statement proved? I also find a similar question in (Spectral gap and local dynamics imply exponent... |
The Greenhouse Gas Theory maintains that an increase in carbon dioxide will cause a corresponding increase in Earth's temperature. But this temperature increase will cause an increase in the flow rate of energy out to space.
At the present temperature of 288 K, the power to space is 239 Wm^-2, and must be maintained a... |
Suppose we have a vacuum tube, inside it there is a beam of electrons traveling inside a gas (argon), according to the ionization energy of the argon it must not exceed the energy of K = e * 15.76V, with 'e' the charge of the electron, so if I get the electrons to travel at a speed less than that energy, is it possible... |
In "Classical Mechanics" by Goldstein and "A Students Guide to Lagrangians and Hamiltonians" by Hamill I noticed that both the virtual displacement derivatives and the normal displacement derivatives are used at different points of the proof, as shown below. My question is why can this mixing of real & virtual derivat... |
I am facing trouble with a statement made after eq 5.2.4 in sakurai modern qm and the statement is $P_1(E-H_0-\lambda P_1VP_1)$ is singular in $P_1$ subspace. How one can we show the validity of the statement?
This question is similar to problem asked previously in this forum but haven't answered appropriately. So I am... |
Assume that we are able to grow a 1 meter long and 5 cm thick Nd:YAG crystal using best possible growth facility. Is it possible to generate a high power Nd:YAG laser using this big crystal?
|
Why is dark matter needed to account for that there's more gravity than there should be, and dark energy for that there's less gravity than there should be?
Obviously that can't be correct, but I'm unable to find a much more precise definition and description of how we know it exists. (An answer that answers this quest... |
I am facing trouble with a statement made after eq 5.2.4 in sakurai modern qm and the statement is $P_1(E-H_0-\lambda P_1VP_1)$ is singular in $P_1$ subspace. How one can we show the validity of the statement.
|
I have heard that in a space with torsion teleparallel curves and geodesics are different and they coincide when the torsion vanishes. But I couldn't find any definition for the teleparallel curve. Please help.
|
In David Simmons-Duffin's TASI lectures on conformal bootstrap, in section 2.4, the author derives the Killing equation (eq. 20) corresponding to spacetime translation symmetry (spacetime dimensions $D>2$), relying on the fact that there is a conserved symmetric stress tensor. I reproduce below the relevant part of the... |
I saw this image from the Wikipedia article on the Franck-Condon principle:
But couldn't find an explanation for the shift $q_{01}$ to the right (i.e. increasing the inter-nuclear distance) as the electron energy level goes from $E_0$ to $E_1$. As far as I understand it, the absorbed energy in an electron will push it... |
My understanding so far:
A wave is a vector field defined on the space-time. i.e. mathematically wave is just a mapping which for every point in the space-time maps it to a vector.
A world-line is function which maps an event (or a particle) on the space-time. In case the event (or the particle) "exists" only for an i... |
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