-1
votes
0answers
11 views

Time variable double slit single photon interference

Has the double slit, single photon interference experiment ever been performed where time is a variable, ie. one photon emitted per day? Would the interference pattern emerge?
0
votes
0answers
5 views

Is diffuse reflection elastic or inelastic scattering of light and how about with spectral?

If images are lost in diffuse reflection does this mean the light will only scatter inelastically or can it be elastic as well?
-1
votes
0answers
30 views

Torque, need help understanding a solution

https://www.scribd.com/doc/100022472/Monbukagakusho-Physics-2010-Solution Problem B. This guy's answer just doesn't make any sense at all to me but he did arrive somehow at the correct solution. If ...
0
votes
0answers
16 views

How does Einstein's curved space time produce acceleration in a free falling object?

I never really thought much about all of this before so I'm definitely a newbie. Please excuse my ignorance. If I understand what I have read so far: if spacetime is curved time would click by at a ...
3
votes
3answers
21 views

Work done on an object by the internal forces

How is the work done by the internal forces acting in a rigid body zero? Actually I read in a book an example for the same. Let me present that example here. Consider a rigid body having two ...
0
votes
1answer
21 views

Do electrons in a CRT emit radiation?

According to electrodynamics, accelerating charged particles would emit electromagnetic energy as radiation. Isn't it applicable to the accelerated electrons within a cathode ray tube? Do they give ...
0
votes
0answers
44 views

How can there be an infinite number of universes? [on hold]

Many proponents of the multiverse (Greene, Krauss, perhaps Hawking) have posited that there may be an infinite number of alternative universes. How could this be possible, or even understood? ...
0
votes
1answer
23 views

Ampere's law and Stokes' Theorem for current density

In both Griffiths and Jackson, Ampere's Law (or conversely the curl of the magnetic field) is derived by applying Stokes' Theorem to the surface integral of the current density J. The argument relies ...
2
votes
0answers
22 views

An example of a theory that respects the Weak Equivalence Principle but violates the Einstein Equivalence Principle

The Weak Equivalence Principle has any one of the following forms: the inertial mass is equal to the gravitational mass there exists a preferred class of trajectories through spacetime, known as ...
0
votes
2answers
35 views

Particle in a box, quantization of energy

I'm learning about how the energy of matter is quantized like how the energy of light is. My textbook illustrates the concept of quantization with the particle in a box: "A particle of mass $m$ ...
-1
votes
0answers
25 views

How many pieces of paper to the length of the observable universe?

Correct me if I'm wrong, but if you fold a piece of paper to the point where it's a long stain of atoms, you would need 601 pieces of paper to get to a light-year. That would mean that you would need ...
-1
votes
1answer
29 views

A problem on Doppler's Effect [on hold]

A source of sound emitting a frequency of 660 Hz is moving counter-clockwise in a circular path of radius 2 m with an angular velocity 15 rad/s. A recorder at a distance from the source is moving ...
3
votes
0answers
21 views

Effective mass approximation

When we calculate the band structure of some solid then we often find that in the bottom of the conduction band the dispersion looks approximately quadratic with some new effective mass: $$E(k) = ...
2
votes
2answers
28 views

How does change in medium affect object distance/image distance?

Say,we have a container filled with a liquid of refractive index $7/5$ upto a height up $H$. There exists a plane glass mirror at the bottom of the container. Now if a fish were placed at a height of ...
0
votes
2answers
20 views

Dependency of buoyancy on volume and mass of submerged object

When we fully submerge a volume of 1 litre, whether that mass is 1 kg or 100 kg, isn't the volume of the displaced liquid always the same and equal to the actual 1 litre, i.e. to the volume of the ...
2
votes
1answer
32 views

EM: relative permittivity

After having defined the relative permittivity in lectures, I have problem understanding why it is a complex quantity. Thank you for your help,
6
votes
3answers
928 views

Why don't metals damp vibrations?

Fluid damps vibrations due to viscous dissipation. Does anyone has any insight on a molecular, microscopic level about the reasons that vibration damping of metals is negligible?
0
votes
0answers
10 views

Are there any specific examples of the application of Lewis-Riesenfeld procedure to time dependent Hamiltonians in QM?

Lewis-Riesenfeld invariant theory is a theory applicable to solve time-dependent Schrodinger equations. I have always encountered the theory related to the procedure, however never encountered any ...
0
votes
2answers
39 views

The elevator and the bolt [on hold]

I had this question, I don't seem to get what I am doing wrong so here it goes:An elevator car whose floor to ceiling distance is equal to $2.7 m $ starts ascending with a constant acceleration of ...
0
votes
0answers
7 views

Plasmon quenching vs plasmon decay. What is the difference?

I'm reading an article "Quenching, Plasmonic, and Radiative Decays in Nanogap Emitting Devices" (pubs.acs.org/journal/apchd5). I don't understand the following: Counterintuitively, we evidence ...
5
votes
1answer
40 views

Spontaneous symmetry breaking of a spinor / vector field

Why does SSB deal only with scalar fields and not with fermion or vector fields? My professor told me that it's closely related to the Lorentz invariance of the theory, but I don't understand at all ...
-1
votes
0answers
17 views

How hail stone is created?

In atmosphere water vapor condense to form water. Since density of water is higher than atmosphere it will come down as rain. Then how hail stones are formed. Before vapor get freezes to ice, why it ...
0
votes
1answer
24 views

How to solve for amplitude w.r.t time for a dad pushing his daughter on the swing with periodic force impulses? [on hold]

A Dad is pushing his daughter on a swing. The homogeneous push lasts for α = 10% of the period and is centered around the phase φ = 0. The Fourier series expansion for this is, $$ ...
-2
votes
0answers
15 views

how to apply capstan law? [duplicate]

I am having trouble to apply Capstan Law. I don't know which side is supposed to be the large force and which the small. If you have a capstan that doesn't rotate, and you have a mass 1kg from one ...
1
vote
1answer
64 views

Is magnetism just electricity in a different FoR?

I am trying to understand magnetism and its relation to electricity: Suppose there are two electrons travelling side by side in deep space at 1 cm distance at .99 c In this article it is said that ...
0
votes
0answers
19 views

Relation between Canonical and Grand Canonical Ensemble for a two levels system

For a two-level system of classical non interacting distinguishable paricles, labelling energy levels as $+\epsilon, -\epsilon$, in the canonical ensemble I found for the partition function ...
-1
votes
0answers
30 views

EM: invariant property in electromagnetic relativity

I have problems answering the following question: "What is an invariant property in electromagnetic relativity? Which of the following is an invariant quantity for the electromagnetic waves?: ...
-1
votes
1answer
33 views

Expectation value [on hold]

Which of the following equations is correct? why?
1
vote
0answers
18 views

Ads/CFT coordinates

I have an AdS space written in Poincare' coordinates and in global coordinates. The transformation that brings one set in the other is a conformal transformation?
0
votes
0answers
25 views

Are alpha and beta rays also generating electromagnetic rays?

To discover radio waves in 1886, Hertz used electric sparks between two iron balls. These sparks caused radio waves which generated a current between other balls. The oscillating charges caused a ...
0
votes
0answers
7 views

problem in making hologram (3 sided) [on hold]

why the image become illusion in transparent glass ? (in making hologram).
0
votes
0answers
32 views

Pauli matrices and $SU(4)$ [on hold]

together with the 2-dim identity matrix, the pauli matrices build a basis of the vector space of the 2x2 hermitian matrices. The set of i*pauli matrices build a basis for the SU(2). Assuming, we ...
2
votes
1answer
35 views

Can a theoretical object exist as such that its mass overcomes gravitational collapse

A daydream the other day led me to the question if "a universe filled with water (or any other substance for that matter), instead of being mostly void" could exist within the rules of our current ...
0
votes
0answers
27 views

Electrical and magnetic energy [on hold]

I have problems answering the following question: What is the ratio of the electrical energy to the magnetic energy stored in a unit volume of the atmosphere just above the Earth's surface, where ...
1
vote
2answers
69 views

Derivation of Euler-Lagrange equation from principle of least action

When deriving the Euler-Lagrange equation for a field $\phi$ the term $$ \int\textrm{d}x^{\mu}~\partial_{\mu}\left( \dfrac{\partial \mathcal{L} }{\partial(\partial_{\mu}\phi)}\right)\delta\phi $$ is ...
0
votes
0answers
10 views

Tidal heating of body

I am trying to make a plausible, though not necessarily accurate model of tidal heating of a body moving close by a gravitational attractor, not necessarily in orbit and not considering the spin of ...
0
votes
0answers
8 views

Infrared Camera spectral filtering with an uncooled camera? [on hold]

I have been doing experiments with thermal cameras and stumbled upon CO2 detection. Having ordered a filter I was full of joy and immediately tried it out - nothing happened. So I talked to the ...
0
votes
0answers
17 views

EM waves: Circularly polarized light incident at Brewster angle

I am having problems in answering the following question: " Circularly polarized light is incident at the Brewster angle on a dielectric surface. With explanation, describe the polarization of the ...
1
vote
2answers
30 views

Thermodynamics : Heat transfer : Conduction or convection?

I have an hot object, that is place in a room of 20°C. My goal is to be able to estimate how warm the object will be in T seconds. To be able to do that, I must first understand what is really ...
-1
votes
2answers
30 views

Simple harmonic motion angular frequency

I'm struggling with this physics question. "A simple harmonic wave of wavelength 16 cm and amplitude 2.5 cm is propagating along a string in the negative x-direction at 35 cm/s." a) Find its angular ...
0
votes
1answer
22 views

What kind of other light sources can disturb the detection of LASER

My project objective is to detect different lasers , for example Laser Range Finder: pulse width 10ns and repetition rate is ...
0
votes
1answer
55 views

Torsion-free, symmetric connection and non-coordinate basis

The torsion tensor is defined as (Hawking p.34) \begin{equation} \mathbf{T}(\mathbf{X},\mathbf{Y}) = \nabla_{\mathbf{X}}\mathbf{Y} - \nabla_{\mathbf{Y}}\mathbf{X} - [\mathbf{X},\mathbf{Y}]. ...
0
votes
1answer
18 views

Under what conditions does a beam splitter entangle two input photons?

There is a dispute on PhysicsForums related to what are the conditions necessary for two photons to be entangled by a beam splitter. Lots of references given by the forum users but they never arrive ...
-1
votes
0answers
12 views

How to Calculate Engine Torque from Drive Torque @ The Wheels for All wheel drive and Front wheel drive? [duplicate]

Would it be possible for someone to explain how engine torque is calculated from drive torque at the wheels and how this differs between AWD and FWD. Thanks.
0
votes
1answer
29 views

How would one attach black hole to starship in the Black hole Starship model? [on hold]

A black hole starship is a theoretical idea for enabling interstellar travel by propelling a starship by creating an artificial black hole and using a parabolic reflector to reflect its Hawking ...
2
votes
0answers
25 views

Majorara zero mode in Ising chain, not exactly zero subtlety

We know the transverse field Ising model with N sites(open boundary), can be mapped into N free fermions(there are 2N modes if including the negative energy counterparts) With property: ...
-4
votes
0answers
29 views

Intuitive understanding of vector spaces [on hold]

I want to understand the intuitive meaning of vector spaces (Hilbert, Banach, metric, normed). I have read a lot of texts and understand the mathematical formalism given but how does it correspond to ...
4
votes
3answers
67 views

How do I find the relation between the accelerations of the ring and the disc (see image)? [on hold]

What is the relation between the accelerations of the ring and the disc (see image)? Both the ring and the disc have mass $M$. The ring has a radius $R$ and disc has radius $2R$. They are connected ...
0
votes
0answers
19 views

Hydropower formula: [on hold]

If I had a 10 kW hydro electric generator (including impeller drive), what formula would I use to calculate how much water per second would need to be pumped into the impeller at 700 kpa to generate ...
1
vote
0answers
23 views

Scale invariance and stress energy tensor

I have seen in a paper [1] that in a quantum field theory scale invariance takes place provided the stress energy tensor is traceless. How this is true? References: "INFINITE CONFORMAL SYMMETRY IN ...

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