-1
votes
2answers
66 views

Why don't electrons moving around in a orbit produce electromagnetic waves in their natural state? [duplicate]

If moving electrons produce changing electric field, and if changing electric field produces magnetic field, every electron must produce an electromagnetic wave. This means an atom in its natural ...
0
votes
1answer
30 views

Can this physical quantity be simplified into a smaller form?

I have a quantity I call fake current. $$ I' = \frac{\mathrm{d} \oint \nabla \mathcal{E} \cdot \mathrm{d} \vec{A}}{\mathrm{d} t} $$ Current is: $$ I = \frac{\mathrm{d} q}{\mathrm{d} t} $$ Charge ...
0
votes
2answers
47 views

Completeness relation for coherent states of the quantum harmonic oscillator

For the Quantum harmonic oscillator with energy eigenstates $|n\rangle$ one defines a coherent state for every complex number $z$ by setting (note that the normalization varies across the literature) $...
0
votes
0answers
8 views

Permeability anisotropy of porous media

Imagine if one were to cut a cylindrical plug out of a perfectly homogeneous rock exactly along one of the principal axis of permeability anisotropy, specifically Kmax. Then, imagine inserting only ...
-2
votes
1answer
42 views

Time dilation of a body A with respect to B [duplicate]

Let there be two bodies a and b. Let a be on Earth and b in space with velocity $(√3/2)c$. Then let the time interval which has passed (on the earth) be twice that of the time interval of which passed ...
2
votes
3answers
446 views

What is the relationship between the magnetic units oersted and tesla?

How are the units oersted and tesla related? For example, how would you express $20\:\mathrm{Oe}$ in tesla?
0
votes
0answers
32 views

I'm confused in this dilemma about pressure [on hold]

Bernoulli principle ensures that when cross-sectional area is small the velocity will increase and so the pressure decrease. So, in a pump the outlet hose area controls the pressure and velocity of ...
2
votes
3answers
78 views

Bell inequality violations evidence for 1935 EPR claims?

Is it possible that Bell inequality tests provide experimental evidence in support for the EPR claims in their 1935 paper titled "Can Quantum-Mechanical Description of Physical Reality Be Considered ...
-5
votes
0answers
40 views

Why is the Heisenberg uncertainty priciple considered as a universal truth? [duplicate]

You should have heard about Heisenberg and his uncertainty principle. I want to know why it is considered as a universal truth, and not a technological limitation. I'd prefer an elaborate answer with ...
3
votes
1answer
46 views

Which temperature does $T$ in Clausius inequality ($\oint \frac{\delta Q}T\le 0$) refer to?

I got a little confused about the temperature in Clausius inequality. As you can see in this answer of Luboš Motl, it seems that temperature is the temperature of the system. But in some answers of ...
3
votes
0answers
39 views

Why do we assume electromagnetic fields to be doubly differentiable? [duplicate]

It seems like the identities of curl of gradient, divergence of curl, and the simple derivations of electromagnetic waves from Maxwell equations all rely on the symmetry (interchangeability of their ...
3
votes
1answer
38 views

How can core of Mercury be a molten liquid?

We all know that Mercury's surface temperature varies a lot from day to night, from 427 °C in a day dropping down to −173 °C at night. Mercury has a hot molten outer core inside it. How can it ...
0
votes
0answers
20 views

Feynman Rules and Feynman Diagrams in QFT by Srednicki [duplicate]

I'm reading Srednicki's Quantum Field Theory. I 'm trying to read Srednicki's presentation of Feynman Diagrams in the chapter Path Integral for the Interacting Field Theory. Link to the textbook: http:...
0
votes
1answer
26 views

Showing phase change for fermions

When discussing identical particles books often use that the states are eigenstates of the permutation operator: $P_{ij}|\psi\rangle = \lambda |\psi\rangle$ for bosons this is easy to see if I use ...
1
vote
0answers
22 views

Black Hole Scattering of Low-Frequency Light

What is the far-field interference pattern for low-frequency (i.e., the wavelength is much larger than the Schwarzschild radius) electromagnetic plane wave radiation about a point mass? I envision a ...
1
vote
2answers
18 views

The difference between sub-Eddington and super-Eddington accretion disk models

I am studying accretion disks around active galactic nuclei (AGN). I have seen two sets of models, sub-Eddington and super-Eddington accretion disks. What do these terms refer to in this case? I ...
2
votes
0answers
19 views

Non-minimal coupling of the gauge fields to the matter

Does any one know the physical meaning of the following gauge invariant gauge coupling to the spinors? $$\bar \psi F_{\mu \nu} [\gamma^\mu, \gamma^\nu] \psi$$ This coupling is not minimal, as $$\bar \...
0
votes
0answers
15 views

Coherence of gauge fixing with the corresponding theoretical gauge freedom

I understand that for a gauge fixing to be valid, it needs to be achievable (i.e., become an identity) continuously through a sequence of allowed gauge transformations of the canonical variables, yet ...
1
vote
1answer
33 views

The interpretation of bubble and oyster Feynman diagrams?

I am reading 'A Guide To Feynman Diagrams in the Many Body Problem' By R.D.Mattuck, in which their is reference to oyster and bubble Feynman diagrams, shown respectively below. In these diagrams I ...
3
votes
3answers
87 views

What is an $\mathrm{SU}(2)$ Triplet?

Under $\mathrm{SU}(2)$ group, a doublet transforms like: $$\phi \rightarrow \exp\left(i\frac{\sigma_i}{2}\theta_i\right)\phi.$$ The doublet looks like $$\binom{a}{b} ,$$ which is easy to understand ...
1
vote
0answers
34 views

How Higgs Field is a constant in an Expanding Universe [on hold]

Going through information on Higgs Field in various forums, it seems that the mass of an object is due its interaction with the Higgs Field which is constant throughout the universe. However it ...
2
votes
2answers
49 views

What is Venus's core made of?

As we all know Venus's surface is so hot that it can probably melt lead. What would be in it's in core? Is it in the liquid or solid state? What would be it's temperature? How many cores does it have?
3
votes
2answers
683 views

Is the reciprocal of Entropy easier to understand? [on hold]

"A thermodynamic quantity representing the unavailability of a system's thermal energy for conversion into mechanical work, often interpreted as the degree of disorder or randomness in the system." ...
1
vote
0answers
37 views

Trouble understanding Nielsen & Chuang exercise

I am probably just stuck on something very simple, but I'm having trouble understanding a premise of Exercise 10.40 in Nielsen & Chuang. The full details of the exercise are not important for my ...
-1
votes
0answers
18 views

Velocities from rotating frame of reference to fixed frame of reference [on hold]

I have the following flexible structure, where P1 coordinate system is fixed to the ground and P3 is rotating around the $y_3$ axes. I would like to model this structure as a simple steady state ...
0
votes
0answers
43 views

Inside computer processors what physical phenomena represents a 1 or 0 [on hold]

I understand how transistors work as switches but am struggling to understand what is detected as the output that is know to be a one or zero. I aim to understand the link between the current flowing ...
0
votes
0answers
15 views

reference request: 2D turbulence

I'm reading papers regarding the 2D Navier-Stokes equations. But I don't have a physics background. Would anybody come up with some introductory references of 2D turbulence which contain the following ...
0
votes
1answer
16 views

What is conductive half space in the context of electromagnetics?

What is conductive half space in the context of electromagnetism? I was looking into skin effect, where the author has used half space of a cylindrical conductor. But I am lost on what it means.
-3
votes
0answers
24 views

Renormalization Group in Condensed Matter [on hold]

Are RG calculations done only in the vicinity of a phase transitions in cond-matt?
0
votes
0answers
28 views

Bulbs glow with different brightness in one arrangement and the same brightness in the other arrangement

The question is: Mr.X decorated his house with fairy lights on a celebration.He bought 40 bulbs and operated at 220V. He found all the bulbs are glowing with different brightness. He called his friend ...
-2
votes
1answer
29 views

Wave nature of light [on hold]

I'm currently working on a project to demonstrate the wave nature of light. Now, my question in specific is: How could the phenomenon of interference be used to MATHEMATICALLY explain the wave nature ...
0
votes
0answers
11 views

How do rockets fly? [duplicate]

Is it that when a rocket loses its mass due to the escaping gases that results in its acceleration due to the same force acting upwards? If so, how is Newton's Third Law associated with it?
2
votes
1answer
61 views

How does a photon 'know' when to reflect in case of refraction? [on hold]

In thin-film interference and in glass fibers refraction is involved. Depending on the angle of which a light ray enters the material it will be reflected or transmitted. The refraction depends on the ...
6
votes
3answers
681 views

Feynman's path integral formulation and faster-than-light paths

In Brian Greene's book "The elegant Universe", he talks about the double slit experiment and Feynman's interpretation of Quantum Mechanics. According to the book, Feynman said that one vaild ...
-2
votes
0answers
30 views

What is Coulumb force at zero separation in classical picture [on hold]

Assume a classical world. What would be force between 2 point charges if their separation tends to zero? Assume charges are static. My professor claimed it would be finite. I request you to ...
0
votes
0answers
22 views

Stuck with 2D kinetics problem [on hold]

I've been trying to solve this exercise for the last four hours and I'm totally stuck. The problems goes like this: Given the mechanism in the image, located in the vertical plane, the OB cord ...
4
votes
3answers
735 views

Space-Time Curvature Depends on Relative Speed

When the mass of a planet causes the curvature of space-time we see that an approaching free-falling object deviates its path towards the planet. We also see the amount of that deviation depends on it'...
0
votes
0answers
16 views

What force is needed to slide a plate off a magnet?

I have read related the wiki article but I am not able to find a solution to my problem: how to find the min force needed to separate a magnet. I suppose that the force exerted by one magnet is ...
1
vote
1answer
40 views

Why is the infinitesimal SUSY variation generated by the sum of a left- and right-chiral generator

I was wondering why in many (all? e.g.https://arxiv.org/abs/hep-ph/9709356) resources on N=1 SUSY the variation of a field in the simplest free susy model is defined as $$\delta_\epsilon \phi = (\...
-2
votes
0answers
23 views

Electric Field around Uniformly Charged Rod [on hold]

Question: A uniformly charged rod (length = $2.0~m$, charge per unit length = $3.0~nC/m$) lies on the x-axis. In consultation with your lecture notes, calculate the magnitude of the electric field at ...
2
votes
2answers
37 views

Spring behaviour under high atmospheric pressure

We have a spring inside a chamber. We compress the spring and then let it decompress freely. Will its decompression (its speed and displacement) be the same if the air pressure of the chamber is $1\;\...
0
votes
1answer
40 views

How to understand CP-violation in kaon systems with Feynman diagrams and matrix elements?

I am trying to understand CP-Violation in the Kaon system using feynman diagrams and matrix element. Here is a slide from Mark Thomson corresponding exactly to what I am looking for (http://www.hep....
-1
votes
0answers
31 views

Question about electric flux [on hold]

Question: Suppose a point charge is located at the center of a spherical surface. The electric field at the surface and the total flux through the sphere are determined. If the radius of the sphere ...
-2
votes
0answers
22 views

Which optics should be used for a long range optic until around 800-1000m? [on hold]

I am planning in making a optics for long ranges to see up to 800-1000 meters. With a magnification of 10x-20x. How could I calculate the details of the objective lens, its diameter of tube and the ...
0
votes
2answers
30 views

Forces on body above body moving at constant velocity [on hold]

Let's say the system is moving at constant velocity. What are the forces applied on B? Is there a static friction force? I find it hard to imagine what is happening to object B. $\Sigma F$ is $0$ on A ...
1
vote
0answers
31 views

From $\gamma$ to $\sigma$, finding proper basis

For $d$ dimensional case, usual gamma matrices have basis $\Gamma^A = \{1, \gamma^a, \cdots \gamma^{a_1 \cdots a_d}\}$ (Let's think about even case only for simplicity, I know for odd case only up to ...
0
votes
1answer
44 views

Can revolving movement also generate gravitational waves? [on hold]

If an object revolves around a circular path at the speed of light could it still generate gravitational waves and what would be the simulation in inner area?
0
votes
1answer
31 views

Effect of test charge on electric field intensity

Obviously on the macroscopic scale, having a test charge being a proton produces no noticeable change in the electric field produced by a charged body. However, on the microscopic level this would ...
0
votes
1answer
23 views

Power factor effects and causes

Why do power utilities impose power factor penalty when power factor goes low (less than 0.7)? Why does the power factor get smaller when the load is much less than the max or rated power of ...
18
votes
4answers
2k views

Why don't loop currents produce light?

If a charge travels in a circle it must accelerate, thereby producing EM. However, a wire in a circular loop is analogous to many charges moving in a circle. So, why don't circular currents produce ...

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