Picture Definition and 402 Threads

Let ##X## be the event that the first draw is a picture card Let ##Y## by the event that the second is a picture card Then the probability that at least one of the cards is a picture card is the probability of ##X## union ##Y## and has the formula Equation 1 ## P\left(X \cup Y \right) = P...

What is wrong (if anything) with this picture?

Has anyone ever taken a "deep field" picture of the sky, like Hubble, but with a radio telescope?

Hi, So I submitted a picture , a .jpeg file, and, at 5.7 mb, I was told it's too large, I need to shrink it. Just how do I do that? I doubt I can zip it. Should I save it in a paint program? Any other idea? Edit: I guess it comes down to increasing the compression ratio. Just if it's simple...

I'd like to get the location of this image in my system

What is the big picture of QFT? I have studied quantum mechanics from: -Griffiths -the first few chapters of Sakurai -Ballentine I have studied electrodynamics from Griffiths and General Relativity from Carroll I have assigned level I to the question, but any answer is welcome

When I'm teaching Advanced QM, I like to include how to describe some processes in the Heisenberg picture (e.g. double slit) so that a student's thinking isn't overly attached to the "dynamics of the quantum state", but they can also understand effects involving operator evolution. This is a...

Here is a picture of the problem It is not clear to me how to really prove that the equation for ##\theta(t)## is simple harmonic motion, and what the period of this motion is.

Reading the introduction to path integrals given in the latest edition of Zee's "Quantum field theory in a nutshell", I have found a remark which I don't really understand. The author is evaluating the free particle propagator ##K(q_f, t; q_i, 0)## $$\langle q_f\lvert e^{-iHt}\lvert q_i...

Hi, I believe that I have an acceptable level of understanding where SRT, GRT, QM and QFT come from. This is not true for me regarding the "good old stuff". Newton, okay, this is relatively (:wink:) clear to me but do you know something about the historical motivation for Lagrangian and...

Last night, on Wednesday, November 9, the KPF team successfully captured a first light spectrum of Jupiter with the next-generation instrument This spectrometer picture of Jupiter has just been taken by the Keck, but I don't understand it. Wiki says Jupter is "89%±2.0% hydrogen" and "10%±2.0%...

Hi. I apologize if this thread is too stupid or if this is the wrong section. I made a drawing a long time ago: This should be "random man", and I bet that in his shirt there is something math/physics-related, maybe a formula. Do you have any idea? I don't remember and nothing comes to mind...

So, I have a hamiltonian for screening effect, written like: $$ H=\sum_{k}^{}\epsilon_{k}c_{k}^{\dagger}c_{k}+ \frac{1}{\Omega}\sum_{k,q}^{}V(q,t)c_{k+q}^{\dagger}c_{k} $$ And I have to find an equation for the time evolution of the expected value of the operator ##c_{k-Q}^{\dagger}c_{k}##. I...

This alert regarding an announcement from the European Southern Observatory – announcement 12th May The results are from the Even Horizon Telescope project which was responsible for producing the first-ever image of a black hole in 2019. The video of that announcement is in the link. Worth...

Hey people, I finally lost my job, i.e. I finally have a few minutes to live my life. I have wanted to have a poster in my room of the Solvay 1927 picture in HD and the colored version. From what I've seen on the Internet, there seem to be different pictures of the scene, probably taken a few...

I've been keeping an eye on this for the last week or so, and today I walked across the street from my work building and had my best laugh in a week. What two main problems do you see in this new fence gate construction? The property across from where I work in Silicon Valley is being torn...

as you see from %[scale=0.8] I tried to scale the picture but it didn't after removing the % \begin{tikzpicture}%[scale=0.8] [declare function = { tilde_y(\q) = sign(\q)*sqrt(abs(\q) / (1 - (abs(\q)-3)^3));}, pics/coordinates/.style args={(#1,#2),(#3,#4)}{ code={ %\draw[help lines] (#1,#2) grid...

I think it is increasing as you move from one level curve to the other with bigger value. Am I right?

Hello! First off, for a), I am not too sure how to picture a radial field around a 3d object. I know that this spherical metal dome is basically a enlarged version of an atom, but since with problems on radial field around an atom, I don't have to consider its diameter, I'm not sure how the...

EDIT: I'M SO DUMB! I can't believe I can't multiply matrices together. Of course the result is not zero, the matrix on the left will be: $$ \begin{pmatrix} 0 & e^{i\omega_at/2}\\ e^{-i\omega_at/2}&0 \end{pmatrix} $$ So i was solving problem 3 from...

Suppose that a particle evolves from point A to point B. The state of the particle can be written as $$\rho=\sum \left | m\right >\rho_{mn}\left< n\right | .$$ Because the basis is evolving as the particle travels, I am considering applying the Heisenberg picture to the density operator. Let...

It's been troubling me for a while, is there some kind of intuitive heuristic picture of why the electron spin g-factor is 2? I remembered this question because of the thread about the nature of spin. One of the early models of spin that were proposed was that it represented the electrons...

I notice that ##pv=t## looks like the ideal gas law but with ##T## in units of energy. I know that ##pV = \text{constant}## means that the pressure of a gas decreases as you expand it (Boyle-Mariotte's law), explaining for instance how we breathe. I guess I could put everything in words even...

Hi friends, Let me brief, long story short.. I am working on an LG plasma TV model 42PQ30R. The fault is no display. The tv is turning on, the blue led is working, however there is no standby (red light), tv automatically going in run mode (i.e blue led) Note: sometimes gets off automatically...

For divergence: We learned to draw a circle at different locations and to see if gas is expanding/contracting. Whenever the y-coordinate is positive, the gas seems to be expanding, and it's contracting when negative. I find it hard to tell if the gas is expanding or contracting as I go to the...

When I look at this picture, the craters seem to have a slight tendency to form rough spirals. (I won't say if they seem to be clockwise or anticlockwise, because I'd like to know what you think -- and I don't want to bias you). So if you feel there is any spirally stuff going on at all, please...

I have some problems when calculating the operators in Heisenberg picture. First, ##\frac {dx} {dt} = \frac {1} {i \hbar} \left [ x, H \right ] = \frac {p} {m}##. Similarly, ##\frac {dp} {dt} = \frac {1} {i \hbar} \left [ p, H \right ] = - m \omega ^ 2 x##. These are coupled equations. I...

I am trying to understand the picture of the metric in terms of the comoving coordinates but it become really confusing for me beacuse every book uses different notation for the same things. So Let's suppose we have a flat 3D Euclidian Space, we can write the metric as, $$dl^2 = dx^2 + dy^2 +...

When a quantum measurement occurs under the Schrodinger picture, the wave function collapses to one of the eigenvectors of the operator-observable and the value measured is the corresponding eigenvalue of that eigenvector. What happens during a quantum measurement under the Heisenberg picture...

If we take the perspective that black holes thermalize (reach maximum entropy) in a very short time and then just sit there and grow in complexity, how do we interpret Hawking radiation in this picture? i.e. you can't just have the state of the black hole keep growing in complexity forever...

When introducing renormalization of fields, we define the "free Lagrangian" to be the kinetic and mass terms, using the renormalized fields. The remaining kinetic term is treated as an "interaction" counterterm. If we write down the Hamiltonian, the split between "free" and "interaction" terms...

Homework Statement:: I'm working with solar heating systems, and my teacher added this picture to his PowerPoint. But I don't understand the picture. Could someone help me? Homework Equations:: The only thing I understand is that ##I_0## is the energy from the sun. But the other arrows confuse...

When working on the interaction picture you can show that in a certain rotating frame the Hamiltonian of a 2-level system (for example) becomes uncoupled. This implies that in such frame there are no Rabi oscillations or other dynamical phenomena, this seems weird to me and I would like to know...

Hi I'm looking at David Tong notes on QHE http://www.damtp.cam.ac.uk/user/tong/qhe/two.pdf (page 56), I've attached the relevant screenshot below also. I understand we are working in the interaction picture whereby states evolve via the Unitary Operataor EQ 2.10 in the notes(I think this is...

https://www.physicsforums.com/attachments/250905 I know the answer, but am not certain how they got Lsin(angle) for R?

A bicycle wheel rolls at a constant speed along a circular path on a horizontal surface. The wheel has a constant angle of inclination to the vertical direction and the distance from its center of mass G to the fixed Z axis is R. Determine the relationship between the angular velocity w1 around...

Summary: I have a question on cosmological redshift which I have just learned about from Sean Carroll. After calculating it for an expanding universe he does a thought experiment to show that it is different to Doppler redshift which would be detected if two galaxies were flying away from each...

While reading the electromagnetic vertex function at one loop, the authors of the book I am reading, wrote down the following vertex function: corresponding to this Feynman diagram: The superscript in ##\Gamma## is the number of loops being considered. My problem is with the equation. I...

As you can see in my attached picture, I am trying to continue on with my text after my embedded image, but it is putting the text still before the image. I'm not sure why it's doing this because I am writing the text after the \end{figure} command. Any ideas?

This is in reference to a question, never fully resolved, posed here: https://www.physicsforums.com/threads/interpretation-of-the-heisenberg-picture-in-qm.816449/ The von Neumann postulates for Quantum Theory - Evolution (Schrödinger's equation) and Projection (Born's rule) are always framed...

In the Schrodinger picture, the operators don't change with the time, but the states do. So, what happen if my hamiltonian depend on time? Should I use the others pictures in these cases?

By the GRAVITY team -

Homework Statement From Griffiths GM 3rd p.266 Consider a free particle of mass ##m##. Show that the position and momentum operators in the Heisenberg picture are given by$$ {\hat x}_H \left( t \right) ={\hat x}_H \left( 0 \right) + \frac { {\hat p}_H \left( 0 \right) t} m $$ $$ {\hat p}_H...

Symmetry transformations are changes in our point of view that preserve the possible outcomes of experiment: $$\Psi \rightarrow U(\Lambda) \Psi$$ In the Heisenberg picture, observables in a fixed reference frame evolve according to: $$P(t) = U^\dagger (t)PU(t)$$ while in the Schrodinger...

Homework Statement https://imgur.com/v13K6sE a uniform rod of mass m is placed as shown, with one of its end resting on a smooth wall while 1/4 of the rod's length is sticking out of a rough table. Find the net force the table exert on the rod at the corner. Homework Equations i drew the free...

Principle, scheme, images of a flying saucer. Reusable spaceship of the future. Spaceship with a solar sail.

Mentor note: Thread moved from technical math section, so is missing the homework template .

I thought this picture of gas swirling into or around a black hole could be up for picture of the day. https://www.sciencedaily.com/releases/2018/10/181031080621.htm

As far as I know, the total cross-sections of the following hadron interactions are well described by a single Reggeon trajectory and a single Pomeron (soft Pomeron) trajectory. ##K^-p: (11.93s^{0.0808}+25.33s^{-0.4525})mb## ##K^+p:(11.93s^{0.0808}+7.58s^{-0.4525})mb## ##\bar...