0
votes
1answer
4k views

Repulsion of the pieces of a broken magnet [duplicate]

Possible Duplicate: Why does it seem like a broken magnet's poles flip? I have experienced that if we break a bar magnet into two pieces and try to bring those broken faces together it ...
2
votes
1answer
269 views

half Skyrmion vs Meron

Is there a difference between a half skyrmion and a meron? I'm asking this in regard to half skyrmion theories of High Tc Superconductors. It would be interresting to know if the proposed half ...
4
votes
1answer
2k views

Compatible Observables

My QM book says that when two observables are compatible, then the order in which we carry out measurements is irrelevant. When you carry out a measurement corresponding to an operator $A$, the ...
0
votes
1answer
1k views

Electrodynamics textbook that emphasizes applications

Which textbook in Electrodynamics which emphasizes practical applications and real life examples would you recommend for undergraduates?
1
vote
3answers
173 views

Results for the path integral formalism for a system with known start and end configuration?

The path integral provides a method for computing a time evolution by a weighted summing up all possible deviations. Is there such a method for a system, where one not only knows the initial ...
0
votes
1answer
449 views

Examples of immiscible or wall-climbing liquids

I am very interested in the physics of immiscible fluids. I would like to ask you if you know any source or list of experiments done by others, with two or three liquids. I am interested in the final ...
3
votes
2answers
2k views

Why electrons are relativistic in Graphene and non relativistic in vacuum?

If a free region in space has a potential difference of one volt, an electron in this region will acquire kinetic energy of 1 eV. Its speed will be much smaller than the speed of light hence it will ...
1
vote
1answer
234 views

Stability of neutron [duplicate]

Possible Duplicate: How come neutrons in a nucleus don't decay? It is known that free neutron decays in 15 minutes on average. Why is it much more stable when "placed" in nuclei? Edit: ...
10
votes
2answers
403 views

What will we see between the CMB and the current oldest object seen?

The cosmic background radiation (CMB) is estimated to be from 13.7 billion years ago (BYA), and very shortly after the big bang compared to that time frame. The oldest coherent objects we've detected ...
1
vote
2answers
179 views

Should $E$ and $B$ change with Gravity?

Lets examine a typical GR metric: $$ds^2=g_{00}dt^2-g_{11}dx^2-g_{22}dy^2-g_{33}dz^2$$ The "d" going with ds has its correct meaning when the path is specified with respect to a one dimensional ...
1
vote
0answers
102 views

The maths/physics in “The Amazing Spider Man” [duplicate]

Possible Duplicate: What does Peter Parkers formula represent? I just saw the trailer for the new Spider Man movie and couldn't help but notice the image after the guy says "How did you ...
2
votes
1answer
536 views

How should a heat current be defined for two component system with unequal numbers

I'm trying to calculate a heat current in a linear response regime of a very weakly-interacting two component low temperature Fermi gas with imbalanced population. I think there are two standard ways ...
2
votes
2answers
903 views

Countersteering a motorcycle

Everyone knows the story about countersteering. For those who don't I will explain it below and after the explanation i will ask my question. You can watch this short video as a beginning: ...
11
votes
3answers
3k views

Why is it necessary for an object to have a bigger size than the wavelength of light in order for us to see it?

I keep hearing this rule that an object must have a bigger size than the wavelength of light in order for us to see it, and though I don't have any professional relationship with physics, I want to ...
1
vote
2answers
620 views

The quantum state can be interpreted statistically, again

Now there are two papers The quantum state cannot be interpreted statistically http://arxiv.org/abs/1111.3328 (It was discussed here the consecuences of this "no-go theorem") And this one (two of ...
19
votes
7answers
8k views

Laplace operator's interpretation

What is your interpretation of Laplace operator? When evaluating Laplacian of some scalar field at a given point one can get a value. What does this value tell us about the field or it's behaviour in ...
2
votes
3answers
563 views

Can a photon be emitted with a wavelength > 299,792,458 meters, and would this violate c?

Just curious if the possibility exists (not necessarily spontaneously) for a photon with a wavelength greater than the distance component of c to be emitted, and would this inherently violate the ...
2
votes
3answers
252 views

Why can't we think of free fall as upside down rocket?

/\ / \ | | | m | | | ------ <--- floor (Rocket A) This rocket is accelerated (g) upwards then mass(m) falls on the floor. ...
3
votes
3answers
716 views

What is the most efficient way to use hand dryer?

What's the most efficient way to place your hands under the hand dryer? Let's assume that dryer creates simple downward flow of hot air. Here are some examples:
9
votes
2answers
784 views

Why does iteratively solving the Hartree-Fock equations result in convergence?

[ Cross-posted to the Computational Science Stack Exchange: http://scicomp.stackexchange.com/questions/1297/why-does-iteratively-solving-the-hartree-fock-equations-result-in-convergence ] In the ...
6
votes
2answers
385 views

Statistical Mechanics treatment of the reaction process?

I'm searching for an at least semi-rigorous Statistical Mechanics description/treatment of a (spatially resolved) chemical reaction process of a macroscopic portion of at least two different species ...
0
votes
2answers
178 views

Is the magnetic field a feature of our universe, or is it a consequence of the electric field?

Is the magnetic field a feature of our universe, or is it a side effect of the electric field? In other words: if we were to simulate in a computer a system of moving charged particles, taking in ...
2
votes
1answer
303 views

Superposition of Ricci scalars [closed]

Suppose I have two point/line singularities in spacetime (what is important to me is that they are localized). Also suppose I have some fields in spacetime and that the two singularities interact with ...
1
vote
2answers
175 views

Fields versus Photons

Does the field of a set of photons behave differently from a single photon. e.g. Suppose I have a group of photons with their Electric fields $\mathbb{E}_n$ all aligned. So $$\mathbb{E}_{\text{tot}} ...
2
votes
2answers
187 views

Differences In Potential Equations

Could someone please describe the differences between the uses each of these potential equations: Potential due to a point charge: $V = \frac{k \cdot q}{r} - \frac{k \cdot ...
14
votes
3answers
7k views

Do all the individual stars that we can see in the night sky belong to Milky Way?

I was wondering if all the stars that we can see with the unaided eye as distinct point sources are from our own galaxy? In other words, can we see stars from the Andromeda Galaxy or other galaxies ...
6
votes
2answers
471 views

what happens to information when black holes merge

When a small black hole mergers with the larger black hole, Would an observer trapped in the smaller black hole be able to detect any difference? Does the observer still exists in the smaller black ...
13
votes
4answers
3k views

What does Peter Parkers formula represent?

Okay, so the trailer for the new Spider Man movie is out and appearently our friendly physicist from the neightborhood came up with something. However I can't find out what this is. ...
1
vote
1answer
360 views

How does compression of carbon atoms work?

From what I understand, it's extremely difficult/ impossible to compress atoms closer together. I'm wondering how this applies in the case of graphite and diamond, where the carbon atoms adopt a ...
3
votes
3answers
907 views

x-ray interaction with atmosphere

Why x-ray are stopped by atmosphere while they are more energetic than UV or IR? They certainly interact with atmosphere but I can't understand which phenomenon stop them.
18
votes
7answers
7k views

How can a human eye focus on a screen directly in front of it?

I am asking this question here because I think the answer has something to do with the way light is bent as it's captured through the eye. I saw a show a while ago about tiny screens on contact ...
2
votes
2answers
332 views

Can x-ray radiation be compared to background radiation?

I've been trying to learn about the possible effects of x-ray radiation from dental x-rays and most of the resources I come across compare the exposure to that of natural background radiation. ...
2
votes
4answers
637 views

Easy to understand equivalents for energy (kilowatt-hour)

Is there a database/webpage/other source for obtaining simple, easy to understand and meaningful equivalents for converted energy by a photovoltaic-site (Wh/kWh/MWh/GWh)? Something like "xxxkWh equals ...
4
votes
1answer
676 views

Energy per particle vs. chemical potential vs. evaporation energy

There is a system of N particles. They interact and are bound together with a binding energy Eb (or potential energy). To characterize the system there are multiple terms Energy per particle Eb(N)/N ...
2
votes
0answers
140 views

About the decay of Higgs into 2 Z bosons

I need to know if I understand this point. The factor of HZZ vertex in the SM Lagrangian is half the value of the Feynman rule which appears in Diagrammatica. When I calculate the decay of Higgs ...
5
votes
1answer
260 views

Does a straight water hose issue water at a greater pressure than a Coiled water hose of same diameter and length?

I have a one BHP water pump, the water pressure of a coiled hose connected to the water pump output side was not that great. Would an unwound water hose produce greater water pressure? [Friction ...
2
votes
4answers
355 views

Books on Hilbert space and phase space?

Can you recommend books or papers that highlight or discuss extensively, or at least more than average, the similarites/differences between phase space and Hilbert space? I am primarily interested in ...
1
vote
0answers
408 views

How equivalent are heat energy and work energy in connection with a spinning flywheel?

Let's say we have two identical spinning flywheels, that have arbitrary geometry, and are made of copper. Now we apply some heat energy at the center point of flywheel A, causing it to slow down a ...
4
votes
1answer
174 views

Is the long range neutron-antineutron interaction repulsive?

I can model this interaction as Zee does in "Quantum field theory in a nutshell". In chapter I.4 section "from particle to force" he uses two delta functions for the source. The integral gives ...
8
votes
2answers
364 views

What are some ways to (approximately) symbolically diagonalize Hamiltonian operator?

Specifically the Hamiltonian takes the form of $$\hat H = \frac{\Delta }{2}{\hat \sigma _z} + {\omega _1}\hat a_1^\dagger {\hat a_1} + {\omega _2}\hat a_2^\dagger {\hat a_2} + {g_1}\left( {{{\hat ...
4
votes
1answer
291 views

SU(2) yang-mills EOM

I'm just playing around tonight trying to better myself, but I'm having trouble with some indices on my yang-mills lagrangian. I have a gauge group $SU(2)$ and a field strength tensor $$ ...
2
votes
0answers
146 views

What forms are theoretically predicted for orbitals or quarks in hadrons and of hadrons in tritium?

We all know very illustrative spatial representations of predicted electron orbitals in atoms which are essentially spatial plots of the solutions of wave equations. In all atoms the electrons occupy ...
3
votes
3answers
2k views

How much energy was consumed when we turn on/off light?

My parents told me to turn off the light when I am not using it. But I remember my physics teacher told me that the action of turning on/off a light can cause huge energy. I am wondering how much is ...
0
votes
0answers
101 views

Book for learning about constructing correct physical modeling [duplicate]

Possible Duplicate: List of good classical physics books I know physics. At least I thought so until I tried to make a model of the system of scales by myself. It was confusing. For example ...
9
votes
2answers
214 views

How big is the Solar System?

How big is the solar system? By "big", I guess I mean "wide", i.e. how far away from the Sun is the farthest object that is considered part of the Solar System? I've checked Wikipedia's pages on ...
3
votes
2answers
358 views

What does a closed time-like curve look like?

I want to see a plot of closed time-like curve in $(t,x)$. $t$ - vertical axis $x$ horizontal axis (the usual setting just neglect $y$ and $z$ components of $(t,x,y,z)$). What does it look like?
1
vote
2answers
487 views

How could this damped oscillator ever go to infinity? Or negative infinity for that matter?

This is an ODE problem,but I cannot visualize why it can go to infinity or negative infinity. Consider $$x'' -6x' + 8x = 0$$ Where $x''$ is acceleration, $-6x'$ is the ...
4
votes
3answers
682 views

Is photon emission possible without electrons changing energy levels?

Does molecular vibrational transition and consequent emission of infrared radiation involve electrons changing energy level? In wikipedia, about vibronic transitions it says "Most processes leading to ...
3
votes
2answers
2k views

What causes destruction in car crash?

Suppose a car crashes at a speed $v$ against a wall and comes to a stop. Now if the car crashes at $2v$, does that mean it suffers twice as much destruction, if that can be objectively measured? If ...
0
votes
2answers
882 views

How to compute drag coefficient given initial position, initial velocity and final resting position?

The equations I'm using are: x = x + (DT * vx) vx = vx * C My DT is always 0.01 and the coefficient C (related to a linear ...

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