0
votes
0answers
158 views

Electroweak Symmetry Breaking

Electroweak symmetry breaking is manifested by the nonzero masses of the weak W and Z bosons, and requires the existence of a Higgs boson or some other yet unseen mechanism. To solve the problem of ...
1
vote
1answer
582 views

What gives matter Gravitational Mass? [duplicate]

Possible Duplicate: Does the equivalence between inertial and gravitational mass imply anything about the Higgs mechanism? In Higgs mechanism, Higgs field, which likes syrup, slows down ...
3
votes
4answers
377 views

Is there any quantum interpretation which isn't “crazy” at all? [closed]

Is there any quantum interpretation which isn't "crazy" at all? Exponentially many parallel worlds in MWI, superdeterministic conspiracies, and/or nonlocality in hidden variables, idealism and the ...
2
votes
2answers
774 views

Lever Mechanics - How to formulate an ideal lever launch

Let's say I have a simple lever as shown below, and the lever is massless and the pivot is frictionless and there is no air resistance. I'm thinking the cradle for the projectile would have to have a ...
3
votes
1answer
238 views

What is relation between Holographic principle and Hologram?

What is relation between Holographic principle and Hologram? The holographic principle is a property of quantum gravity and string theories which states that the description of a volume of space can ...
0
votes
1answer
249 views

Wavefronts and phase velocity faster than $c$

Lets assume we have parallel wavefronts in a glass of water: and we put an inclined rod on the water surface: related to a very small inclining, Vy velocity is greater or much greater then Vx ...
3
votes
1answer
354 views

Is it possible that nuclear fission contributes to climate change?

This is probably a really stupid question, please forgive me. Is it possible that the use of nuclear fission on earth contributes to the increased energy in the Earth's system as according with the ...
1
vote
1answer
142 views

converting daily global radiation into hourly values

I would like to convert daily global radiation into hourly solar radiation. While I do not know the terms, I tried using below equations I found in the papers but I have negative radiation values ...
9
votes
1answer
372 views

Does string theory provide a physical regulator for Standard Model divergencies?

In other question, Ron Maimon says that he thinks string theory is the physical regulator. I did not know that string theory regularize divergencies. So, Q1: How does string theory regularize the ...
7
votes
4answers
3k views

How to prove that proper orthochronous Lorentz transformations form a group?

Proper orthochronous Loentz transform are Lorentz transforms that satisfy the conditions (sign convention of Minkowskian metric $+---$) $$\det \Lambda=+1, \qquad \Lambda^0{}_0 \geq +1.$$ How to prove ...
2
votes
1answer
225 views

Zero entropy change

If you put a object in contact with a heat reservoir that is infinitesimally higher in temperature than the object and allow equilibrium to be reached the entropy change is zero right?
4
votes
2answers
311 views

Why magnetic monopole found in spin ice don't modify the Maxwell's Equations?

Magnetic monopole predicted by Dirac nearly a century ago was found in spin ice as quasi-particle(2). My question is Why magnetic monopole found in spin ice don't modify the Maxwell's Equations? (I ...
2
votes
2answers
417 views

Force and Natural Units

Today in my Physics lecture I suddenly thought of something. We all know that gravitational force is proportional to the two masses and inversely proportional to the square of the distance between ...
0
votes
1answer
86 views

Modeling falling spheres

The following situation interests me and I was wondering if there is software to model it? A large set of n spheres of uniform density and discrete sizes, mass proportional to volume, are dropped ...
5
votes
1answer
309 views

How do I measure the temperature of a tiny water droplet?

How do I accurately (+/- 0.1 degrees Celsius or better) measure the temperature of a small (5 to 50 microliter) water droplet without noticeably affecting its temperature? The mass of a thermistor or ...
5
votes
1answer
308 views

Relativistic contraction for a wave packet and uncertainty on momentum

Consider an electron described by a wave packet of extension $\Delta x$ for experimentalist A in the lab. Now assume experimentalist B is flying at a very high speed with regard to A and observes the ...
-1
votes
1answer
360 views

Distance and displacement of an object on a straight line [closed]

I had this homework problem, but don't actually know if what I did is right, or that I even read the problem correctly. Can someone please tell me if this is the right interpretation of the problem ...
11
votes
3answers
2k views

Gentle introduction to twistors

When reading about the twistor uprising or trying to follow a corresponding Nima talk, it always annoys me that I have no clue about how twistor space, the twistor formalism, or twistor theory works. ...
9
votes
3answers
212 views

Is the magnetic field of a white-dwarf merely residual?

Follow-up to my other question How does Sol's magnetic field continue to exist at such high temperatures? Assuming Sol's magnetic field is generated by convective currents in it's plasma, how is ...
4
votes
2answers
246 views

What is the most natural classical polynomial complexity class that includes all of BQP and NP?

Since we know that there are some oracle problems which can be solved on a quantum computer, but not on an NP machine with the same oracle, the idea of nondeterministic (i.e. infinitely parallel) ...
2
votes
0answers
103 views

Searching for a specific Feynman quote [closed]

Pardon that this is strictly speaking not a question about physics but about a quote about physics, but I'm not sure where else to turn to. A while back I read a quote by Feynman in which he says ...
0
votes
1answer
3k views

Work on ideal gas by piston

Imagine a thermally insulated cylinder containing a ideal gas closed at one end by a piston. If the piston is moved rapidly, so the gas expands from $V_i$ to $V_f$. The expanding gas will do work ...
10
votes
1answer
535 views

How much does the curvature of space change the volume of Earth by?

If we assume space is flat the volume of Earth is: $$ V = \frac{4 \pi R^3}{3} = \frac{4 \pi (6378.1 km)^3}{3} = 1.086 \times 10^{21} m^3 $$ The Einstein field equations, however, predict that the ...
4
votes
2answers
2k views

Where does the lost energy go in a rubber band powering a rotating shaft?

Okay, I'm no physics whiz, and this has me stumped. You know those toy airplanes you can get with the rubber-band driven propellers? You twist the propeller a bunch of times, and this stores ...
0
votes
1answer
1k views

How does one solve the Schroedinger equation for a 2D, time-dependent harmonic potential?

This is the Schroedinger equation with a particular 2D harmonic potential: $$\begin{multline}i\hbar\frac{\partial}{\partial t}\Psi(x_1,x_2,t) = \\ \Biggl[-\frac{\hbar^2}{2m}\nabla^2 + \frac{1}{2} ...
0
votes
2answers
167 views

Dimension analysis of de Broglie equations

One form of one of the de Broglie's equations is this: $\lambda = \frac{2\pi\hbar}{p}$ Units: $\lambda = [m]$ $\hbar = [Js]$ $p = [\frac{kg m}{s}]$ $J=[Nm]$ How can one show with dimension ...
1
vote
2answers
185 views

Physics and what it means [closed]

I got into a debate with a friend about the meaning of physics and its purpose, he is the sort who will test you and if you get it wrong it somehow gratifies his own self-reflection and self-worth. ...
1
vote
2answers
334 views

What exactly is superconductivity?

Does superconductivity mean that the coulomb force or some magnetic force has gone up? I guess that it applies only to wires which get less resistance due to cooling... Is this wrong? Also, Are there ...
0
votes
1answer
381 views

Power, Force Velocity

In any case, if the force and power is constant , does velocity also need to be constant? If no, can you tell me a case. Further can this be extended for non-rigid bodies.
3
votes
0answers
99 views

positronium BEC stability

After reading this article regarding Positronium BEC formation (for lasing purposes), there is a mention in there regarding Ps "up" atoms not annihilating with "down" atoms, the article is pretty ...
2
votes
3answers
717 views

Simple work and energy problem [closed]

I have the following problem: A man that weights 50kg goes up running the stairs of a tower in Chicago that is 443m tall. What is the power measured in watts if he arrives at the top of the tower ...
1
vote
1answer
206 views

Why does the running of the gauge couplings show $\frac{1}{\alpha}$ > $\frac{1}{\alpha_w}$ at low energy?

I thought the coupling constants were something like: $\alpha \approx 1/137$ $\alpha_w \approx 10^{-6}$ $\alpha_s \approx 1$ And yet if you look at any pictorial representation of the running of ...
3
votes
3answers
427 views

Magnetic paradox in relativity?

Let 2 electrons A and B be moving parallel with constant velocity $c/10$ in (near) vacuum without a strong gravity field (where $c$ is speed-of-light). A and B create an electromagnetic field that is ...
0
votes
1answer
128 views

Light in the absence of colloids?

If Earth had no colloids (Don't take LIFE into account) or any kind of scattering medium (like atmosphere) that promote to Tyndall effect, how would we able to receive the sun's rays? In the other ...
1
vote
1answer
6k views

Calculation of Distance from measured Acceleration vs Time

I have an Accelerometer connected to a device that feeds the instant values of the acceleration in the 3 directions. I've tried to calculate the distance for a vertical movement using these values ...
17
votes
4answers
3k views

Introduction to AdS/CFT

AdS/CFT seems like a really hot topic and I'd like to start reading about. I am looking for the best introduction at my level, i.e. I have a background in QFT, CFT and general relativity at the level ...
1
vote
3answers
166 views

How to incorporate effects of gravity in a many-electron system?

In the weak interaction limit, behaviors of electrons can still be described by a 1-partitcle equation with a modified mass, where the change in mass can be understood as effects of other neighboring ...
2
votes
2answers
106 views

Commutation for constraints

Suppose from the Hamiltonian I got the Primary constraints $$(\Phi_m,\Phi)$$ And $\dot \Phi_m$ , $\dot \Phi$ leads to secondary constraints $$(\gamma_m,\gamma)$$ respectively. Now if the commutation ...
8
votes
4answers
12k views

What is the color of a mirror?

A mirror couldn't be white, as then you wouldn't be able to see your reflection so clearly. It wouldn't be transparent, as that then won't reflect. So what color is it?
0
votes
2answers
1k views

Does travelling light help us see past versions of an object?

I saw a passage in my son's homework book, constructing a scenario in which a person standing on a planet 65 million light years away from Earth, with an extremely powerful telescope pointed at Earth, ...
1
vote
0answers
41 views

In heterojunction problem, how to align the energy band in presence of bias voltage

For example, SiO$_2$ barrier embeded between Fe magnet and 2-dimensional-electron-gas such as Si. How to align the energy bands of the three materials when an electric field is perpendicular to the ...
-1
votes
2answers
148 views

Simulating a car in an intersection

I'm somewhat confused. I want to simulate in real-time an intersection where cars have to turn left, right or go straight. What I have are 2 way points: One at the beginning of the intersection on ...
9
votes
5answers
2k views

Crash course in classical thermodynamics

I've been working on some projects lately where it would be very handy to know more about thermodynamics than I do, but sadly I never had a chance to take a proper thermodynamics course in college. ...
6
votes
2answers
554 views

Linearizing Gravity to ${\cal O}(h^3)$

I've seen the action of linearized gravity in many places. We basically have $${\cal L} ~\sim~ \frac{1}{G_N}\left( - \frac{1}{2}h^{\alpha\beta} \Box h_{\alpha\beta} + \frac{1}{4} h \Box h + {\cal ...
1
vote
0answers
49 views

Random quantum systems with asymmetric Lifshitz tails?

For a quantum mechanical system with a periodic Hamiltonian (Schrödinger operator) $H$, let $N(E)$ be its integrated density of states, i.e. the fraction of eigenvalues in the spectrum $\sigma(H)$ ...
3
votes
2answers
704 views

Water from Icebergs

Thousands of icebergs are calved from polar regions annually, and melt in the oceans. George Mougin, an entrepreneurial engineer, aspires to tow multi-million ton icebergs to areas of the world ...
3
votes
2answers
3k views

What is the luminosity per square meter hitting the Earth's surface from the Sun?

So I know that the Sun's luminosity is $3.839 \cdot 10^{26}$. What I want is the luminosity per square meter at the Earth's surface. So this is what I have got so far: I know the distance to the ...
2
votes
1answer
521 views

Where are the harmonics in the radio spectrum?

When I strike a string on my guitar and look at the audio spectrum, I can see the fundamental frequency as a large peak. I can also see the harmonic frequencies as a train of little peaks at ...
3
votes
1answer
3k views

How to find focal length of a single convex lens?

I need help finding the focal length of a single convex lens. The radius of curvature is 200mm. left side is air and the glass has a index of 1.5. I search on google but there was only formulas for ...
0
votes
0answers
158 views

Quantum Mutual Information scaling

Wikipedia provides a simple definition of Quantum Mutual Information: $$I(\rho^{ab})= S(\rho^{a}) + S(\rho^{b}) - S(\rho^{ab})$$ where in terms of relative information we have: $$I(\rho^{ab})= ...

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