1
vote
2answers
33 views

Compressibility factor and deviation from ideal gas behaviour

I have recently started to study the deviation of ideal gas behavior. The source from which I am reading doesn't give me an intuitive understanding of the compressibility factor. I dont understand how ...
0
votes
0answers
18 views

(Iso)spin coupling of three particles

I need Isospin calculations to predict the relative amount of strong decays, namely $D^{**0}\to D\pi\pi$, where the $D$ and $\pi$ can be charged or neutral. My problem is the order of contracting the ...
0
votes
0answers
19 views

Communication between two LEO satellites

Anybody have any idea about any mathematical model to allow communication between two LEO Satellites is possible in space, where two LEO satellites do not know their positions in two different polar ...
1
vote
0answers
16 views

Video lectures for studying graduate level kinetic theory

As the title says it all, I require Video lectures for studying graduate level kinetic theory including but not limited to detailed analysis of viscosity and conductivity, diffusion and Maxwell's ...
1
vote
0answers
52 views

Generalisation of a particle in QFT

In classical mechanics, we assumed a particle to have a definite momentum and a definite position. Afterwards, with Quantum mechanics, we gave up the concept of a time-dependend position and momentum, ...
0
votes
1answer
42 views

Even when the drift velocity of the electrons is very small, how is current in the circuit established immediately?

So I have this question in my textbook and Ive also got it in my test. Ive written a wrong answer. My friend wrote the drift velocities of each particle add up and he got full marks. Is it right? Can ...
1
vote
1answer
20 views

How can I calculate the torque on a body resulting from a spinning propeller?

If a quadcopter has all of its propellers spinning on the same direction, the body of the quad will obviously start spinning in the another direction. I know how to calculate the torque acting on a ...
0
votes
1answer
32 views

A question about heisenberg uncertainity principle

In my textbook about atomic structure we have a brief part about Heisenberg uncertainty principle. While the derivation was not given in the book which simply stated Heisenberg as $\Delta x\, \Delta p\...
2
votes
0answers
19 views

How rigorous is the description of the edge of the Kitaev Honeycomb as a CFT?

My understanding of the Kitaev honeycomb model is that high-level abstract properties (anyons and their braid statistics) can be seen to emerge the microscopics of the model (fermions and vortices). ...
3
votes
0answers
43 views

Lagrangian of classical electromagnetism without $A_{\mu}$ field [duplicate]

Is there a Lagrangian reproducing Maxwell's equations without the use of the scalar and vector potential? Obviously $\mathcal{L} = -\frac14F_{\mu \nu}F^{\mu \nu}$ doesn't work since in terms of $E$ ...
1
vote
1answer
39 views

Why don't windows and mirrors cancel light?

So I understand that when light goes from a material of low index to a material of higher index it picks up a phase change of 180. Most glass has an index of around 1.5. I know that when light goes ...
-1
votes
0answers
20 views

Force needed question [on hold]

I am standing on a ladder 24 ft. in the air,The angle of the ladder is 65 degrees and I weigh 200 lbs and the ladder weighs 65 lbs ,How much force would be needed to lift the ladder off the ground,...
-1
votes
2answers
29 views

Lagrangian mechanics not relying on time or independent of time [on hold]

If neither the potential energy nor kinetic energy depends on time, then Lagrangian is explicitly independent of time I find this statement a little bit odd because velocity is distance over time or ...
-1
votes
0answers
39 views

Understanding mathematical role of physics [on hold]

I have just started my undergrad physics degree but mathematics professor isn't good here in this faculty because he doesn't hold the ability to tell good physical examples on how this math is working ...
-1
votes
0answers
49 views

Plotting a Function [on hold]

I have the following result: $$ n_z(t) = 1 - 8 \sum_{k = 0}^{\infty} |g_{k}|^{2} \frac{\sin^2 \Big (\frac{(w_k - w_{0})t}{2} \Big)}{(w_k - w_{0})^2} $$ I want to figure out the dependence ...
3
votes
2answers
46 views

Moving of spin up and spin down electrons in a magnetic field

Suppose we have an electron in a conducting space, and now we apply a magnetic field. Now according to the right hand rule, the electron will have a circular motion in the plane perpendicular to the ...
-1
votes
0answers
77 views

Constrained motion [on hold]

All speed shown are with respect to ground. Then we have to find the speed of block B with respect to ground. I tried it by two methods, but got different result why?
2
votes
1answer
34 views

Maximum range in projectile motion (elliptical path)

Elementary Newtonian mechanics tells us that if a projectile is shot at 45 degrees from the ground, and a downward gravitational field is acting on it, it will follow a parabolic path and achieve ...
0
votes
0answers
26 views

Buckling of elastica

The simplest equation for buckling of a beam is \begin{equation} y''''(x) + \rho \, y''(x) = 0, \end{equation} where $y(x)$ is the displacement from the base state and $\rho$ the ratio between the ...
0
votes
2answers
27 views

Why is the water still in the glass while rolling?

Pilot drinks glass of water while rolling the plane. The water stays in the glass, even if the plane is upside down. How is this possible? Why doesn't the water leave the glass, as it does when I ...
0
votes
0answers
39 views

Static vs Dynamic pressure?

According to Bernoulli's law, the narrower the tube where the fluid is flowing the lower its static pressure and the higher its dynamic pressure. Does this make any difference anyways, if the dynamic ...
1
vote
3answers
39 views

Two qubits system in polar co-ordinates

I know that I can write a single qubit state in terms of polar co-ordinates $(r,\theta,\phi)$ on a Bloch sphere. \begin{equation} \rho = \begin{pmatrix} \frac{1+r \cos\theta}{2} &\frac{r \exp(-i\...
4
votes
3answers
489 views

Is there any effect on mechanical waves by electromagnetic waves (and vise versa)?

Do electromagnetic waves like light and gravitational waves (due to moon for instance) affect on mechanical waves like sound? Can sound change the path of light?
0
votes
0answers
21 views

Wave equation for odd spacetimes and source terms

It seems to be quite common practice, when solving the wave equation in spacetimes with odd topologies or horizons, to decompose the solution into a sum of the various origins (or destinations) of the ...
2
votes
1answer
58 views

Metric with Harmonic Coefficient and Stress-Energy Tensor in General Relativity

I have two question: Is there any possible implies or interest to use in general relativity a metric whose coefficients are harmonic functions? What is the meaning (physical) if the stress-energy ...
-1
votes
1answer
34 views

Vibrations of a string [on hold]

A string with length $L$ is stretched between two fixed points. The string can't vibrate with which wavelength? Four options are given, namely $L$, $L/2$ , $2L$ and $4L$. I know that the ...
-3
votes
0answers
16 views

Are electrons packets of energies made up of strings? [on hold]

I always wondered that if electron was a packet of energy it would hold true for most of the experiments and we won't need to deal with wave particle duality anymore,but then matter came in.what if ...
0
votes
1answer
28 views

Tention in a string with pulley and two objects at opposite ends

Tension is confusing me. According to my understanding of tension the tension in a string is uniform but while going through the solution of a problem I read that tge tension on the left part of the ...
-2
votes
0answers
31 views

Imagine I'm on a spacecraft that was accelerated to 1.0$c$ could I only move backwards? [duplicate]

Imagine I'm in a sapcecraft1 that is moving with 1.0$c$ or at least is so close to that speed that a few miles per hour would just be left to reach $c$. So when I'm traveling now in the direction ...
1
vote
0answers
35 views

Building a solid foundation for Quantum Information [on hold]

For the student with a keen interest in Quantum Information, what would be a sound course/set of prerequisites(possibly along with a few good resources) in Math, Physics, Computer Science, Electronics ...
5
votes
2answers
55 views

How much mass must Earth lose to lose its Moon?

Maybe I am wrong about the basic concept here, but for my curiosity: how much mass would need to leave the Earth (like satellites and rockets) to create an imbalance between the Earth and Moon so that ...
2
votes
0answers
36 views

What is the cause of the minor mass difference between the proton and the neutron?

As known, the proton is from two up and a single down quark, while the neutron is from a single up and two down quarks. The down quark is a little bit more massive and the up, and so the neutron is ...
0
votes
0answers
20 views

What exactly were the “asymmetries which do not appear to be inherent in the phenomena” in Einstein's 1905 SR paper?

The first ¶ of Einstein's "On the Electrodynamics of Moving Bodies" says (my emphases): It is known that Maxwell's electrodynamics—as usually understood at the present time—when applied to moving ...
0
votes
0answers
11 views

Spin half particle Magnetic field oriented along y-axis

I've been looking over past papers for an upcoming QM exam and have had a few issues wrapping my head around this question. I can follow the common example as seen in Griffiths where the field is ...
6
votes
2answers
143 views

Why hermitian, after all? [duplicate]

This question is going to look a lot like a duplicate, but I've read dozens of related posts and they don't touch the subject. Here we go. Why are observables represented by hermitian operators? ...
-1
votes
0answers
28 views

Luminiferous æther = quantum's “vacuum”? [on hold]

How is the luminiferous ether, which relativity theory disregarded, different from and similar to what in quantum mechanics is called "the vacuum"?
3
votes
2answers
23 views

Force applies to sphere not on center of mass?

Is this true: When force is applied to a sphere NOT on center of mass (COM) then the sphere will move the same way as when force is ON center of mass, because the sphere is symmetric in every ...
-3
votes
1answer
38 views

Who will feel more pain when jumping from a height, a tall man or a short man?

Whether the impact on a tall man is greater than a short man when he jumps from a height?
2
votes
2answers
47 views

Does QFT modifies Quantum Mechanics? [duplicate]

The basis of Quantum Mechanics is contained in the postulates which tell us how to describe quantum systems (below I disconsider possibly degenerate spectra just for simplicity): To describe a ...
1
vote
3answers
37 views

How does an hydraulic ram pump work?

Hydraulic ram (wikipedia)(youtube) uses the water hammer (wikipedia) to pump water. Please help me understand how it works. I understand that the check valve catches the pressure from the water ...
1
vote
2answers
39 views

Distortion of interference pattern at LIGO

Does the vibration due to the earthquakes distort the interference pattern of LIGO's interferometer?
4
votes
1answer
48 views

How to define the distance between two points in a conformal transformed space?

Consider a particular conformal transformation $x^\mu\rightarrow x'^\mu$, and the metric of a flat space transforms in the following way, $$\eta_{\mu\nu}\rightarrow g'_{\mu\nu}=\Lambda^2(x)\eta_{\mu\...
0
votes
0answers
19 views

Derivation of differential governing equation of Hartnell governor? [on hold]

I tried to derive the differential governing equation using energy conservative method and newton's second law, but I came up with very large and complex equations, even with assumption of small angle ...
1
vote
1answer
45 views

What does coherent superposition mean?

There is only one coherent state: $$|\alpha\rangle=e^{-\frac{|\alpha|^2}{2}}\sum_{n=0}^\infty \frac{\alpha^n}{\sqrt{n!}}|n\rangle $$ Also, a pure state does not mean a coherent state. But when does ...
-2
votes
3answers
55 views

What is acceleration of A and how to approach such accelerating pulley problem [on hold]

As shown in figure A and B are free to move pulley and rope are mass less, there is no friction at all between any two. Now my question is because of tension in rope, A will move left but how will B ...
0
votes
0answers
18 views

Spin structure for SOC spin-1/2 system

It is well known that we have a $\mathbb{Z}_2$ extension of any symmetry group acting on a half-integer spin fermion system. Now if we also have spin-orbit coupling, what is the spin structure that we ...
-1
votes
0answers
31 views

Interpreting conical intersection in quantum adiabatic evolution

Recently, I have studied a particular quantum adiabatic algorithm. When I plot the eigenvalues of the ground and first excited state against normalized time $s$, there appears a conical intersection. ...

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