5
votes
2answers
371 views

Why does a firebrand glow brightest before it burns out?

I've noticed this in match-sticks, and mango wood. After the flames die out, the brand glows red for a while. The glow is brightest right before it dies out. My guess is that immediately before the ...
34
votes
4answers
292 views

Models of neutrinos consistent with OPERA's results

I guess by now most people have heard about the new paper (arXiv:1109.4897) by the OPERA collaboration which claims to have observed superluminal neutrinos with 6$\sigma$ significance. Obviously this ...
18
votes
1answer
1k views

What happened to the idea of tachyonic or other superluminal neutrinos?

While hunting around for information about the recent OPERA measurement that hints at superluminal neutrinos, I discovered that this idea was actually considered back in the 1980s. Wikipedia lists as ...
4
votes
2answers
821 views

What is the physical process (if any) behind magnetic attraction?

I understand that the electromagnetic force can be described as the exchange of virtual photons. I also understand that it's possible for virtual photons, unlike their real counterparts, to have mass ...
1
vote
0answers
153 views

What would the impact be on the physics world if neutrinos DO travel faster than light? [duplicate]

Possible Duplicates: What would be the immediate effects if light does not go at the maximum speed possible? Superluminal neutrinos I was reading this article about a group of scientist ...
18
votes
6answers
4k views

What would be the effects on theoretical physics if neutrinos go faster than light?

Earlier today, I saw this link on Facebook about neutrinos going faster than the speed of light, and of course, re-posted. Since then, a couple of my friends have gotten into a discussion about what ...
74
votes
14answers
7k views

Superluminal neutrinos

I was quite surprised to read this all over the news today: Elusive, nearly massive subatomic particles called neutrinos appear to travel just faster than light, a team of physicists in Europe ...
5
votes
3answers
2k views

How would you store heat?

Um .. naive question perhaps but if somebody wanted to store heat, how would they go about it? Can heat be stored? I'm told that decomposing kitchen waste in a closed vessel results in a rise in ...
2
votes
2answers
1k views

Characteristic length, characteristic time and complexity of the process

Different physical processed (starting from elementary particles or even below to the universe itself) have different length scales $L$ and different characteristic times $T$. Larger processed tend to ...
2
votes
1answer
265 views

Looking for specific Relativity example

Many years ago (in the '70s I think) I read an explanation of the meaninglessness of simultaneity at large distances. The example had to do with two people walking along a sidewalk in opposite ...
4
votes
1answer
11k views

Why is my tupperware sealed after heating it up in the microwave?

I had a vegetable soup in a crystal tupperware and I put it in the microwave to heat it up. The funny thing is that when I took it out, it was impossible to open it up. The lid is bent towards the ...
1
vote
1answer
149 views

Separation of solids from liquids using magnetic waves

Using magnetic forces, I want to separate solids from liquids in a solution as a centrifuge would do. Is there a way to hit a volume of liquid and get it to separate liquids and solids with heavy ...
15
votes
4answers
683 views

What is a good introduction to integrable models in physics?

I would be interested in a good mathematician-friendly introduction to integrable models in physics, either a book or expository article. Related MathOverflow question: what-is-an-integrable-system.
4
votes
2answers
407 views

Introduction to relativity books for an engineer [duplicate]

Possible Duplicate: Getting started general relativity I am an engineer who loves to read science fiction books especially when there's more science than fiction but usually I see that I ...
5
votes
1answer
181 views

Gravitational lensing from an extended body Vs. a point mass

I am interested in gravitational lensing caused by a cluster of galaxies (say it has a diameter of 1 Mpc and mass of $10^{12}$ solar masses). How close must a light travel as it passes by to be ...
3
votes
1answer
284 views

Spontaneous emission and induced radiation

In Einstein A., Zur Quantentheorie der Strahlung, Phys.ZS., 18, 121-137 (1917) spontaneous emission is considered to occur together with induced radiation so that one can write the following condition ...
3
votes
1answer
259 views

How much power can be drawn from stray electromagnetism in the atmosphere?

I know this probably varies quite a bit from place to place on earth. But just some rough estimates: if I were to pull power via multiple antennae tuned to a variety of different frequencies, how much ...
3
votes
1answer
4k views

When does voltage drop occur?

Why or when does it occur in a circuit? What does it imply when you speak of a voltage drop across a resistor? (Obviously, it probably means that the current's voltage before the resistor is higher ...
33
votes
8answers
3k views

Does Gödel preclude a workable ToE?

Gödel's incompleteness theorem prevents a universal axiomatic system for math. Is there any reason to believe that it also prevents a theory of everything for physics? Edit: I haven't before seen ...
11
votes
0answers
392 views

Hypersingular Boundary Operator in Physics

This has been a question I've been asking myself for quite some time now. Is there a physical Interpretation of the Hypersingular Boundary Operator? First, let me give some motivation why I think ...
-3
votes
1answer
69 views

Minimum criteria for quantum state dissolution

What are the minimum conditions required to cause the colapse of the quantum state ? Or, what forces/equations determine when an object (for instance an electron) is forced out of its quantum state in ...
65
votes
2answers
6k views

Why do we not have spin greater than 2?

It is commonly asserted that no consistent, interacting quantum field theory can be constructed with fields that have spin greater than 2 (possibly with some allusion to renormalization). I've also ...
6
votes
3answers
329 views

“Reverse engineering” of a horoscope?

I'll start with a disclaimer -- this is not a question about astrology itself, I'm neither trying to refute nor to defend astrology. I'm interested in purely technical things, which are mostly ...
6
votes
1answer
1k views

What is the penetration length of static electric field into conducting metals?

How large is the penetration length for static electric field into good conductors? I have two versions: (1) few atomic spacings $$a\sim n_{e}^{-1/3},$$ and (2) Debye length computed by Fermi ...
0
votes
1answer
143 views

Use of escort distribution in nonextensive stat. mech

In some of the articles which I read recently, I happen to see the following statement. In Nonextensive statistical physics, it is inappropriate to use the original distribution $P=(p_i)$ ...
3
votes
1answer
351 views

Why is Dirac Lagrangian in Curved Spacetime Weyl Invariant?

Are there any references on the Weyl invariance of the Dirac Lagragian in general spacetime?
3
votes
1answer
153 views

What does “single inclusive” mean exactly?

I thought I knew what single inclusive scattering was, but today when I went to look up a definition to check my memory, I couldn't find one. A Google search yielded no shortage of papers that use the ...
2
votes
1answer
601 views

Schwarzschild black hole geometry in Novikov coordinates

As I am a layman in gravitation I would really appreciate any suggestions on how to approach and tackle the following problem: Choose a time-symmetric 3-geometry for the initial geometry of ...
13
votes
2answers
389 views

Applications of the Feynman-Vernon Influence Functional

I am looking for a reference where the Feynman-Vernon influence functional was defined and used in the context of relativistic quantum field theory. This functional is one method to describe ...
8
votes
1answer
44 views

New Type of Type Ia supernova. Implications to Dark Energy measurement?

As I understand it, we used Type Ia supernovas to determine that there is some sort of repulsive force (which we call dark energy) making things fly away from us at an accelerated rate. The reason we ...
20
votes
5answers
189 views

Connections and applications of SLE in physics

In probability theory, the Schramm–Loewner evolution, also known as stochastic Loewner evolution or SLE, is a conformally invariant stochastic process. It is a family of random planar curves that are ...
1
vote
3answers
157 views

Question about orthonormal decompositions over unitary operators

I'm teaching myself quantum information theory using Nielson and Chuang's "Quantum Computation and Quantum Information" and I'm at a point in the book where the formalism is starting to make my eyes ...
4
votes
1answer
34 views

Contents page of Exoplanets book

I can't find an online contents page for the book Exoplanets, edited by Sara Seager, University of Arizona Press, 2011. Can you point to such a page, or say what the contents page says?
3
votes
2answers
530 views

an example of a quantum system for which wigner function transitions to negative values

I want to check my understanding of the Wigner transform and try to understand why and how exactly the probabilistic interpretation drops down as the function goes to zero and then to negative values ...
3
votes
0answers
163 views

What kind of shape has the lowest flutter wind speed?

What kind of shape has the lowest flutter wind speed and is the most unstable? I mean for rigid body. Thanks Yes, I know many factors affect the flutter in a MSD system (for rigid body), however ...
14
votes
1answer
179 views

Do Gauge Theories (CFTs) Have Phase Transitions as the 't Hooft Coupling is Varied?

With an eye toward AdS/CFT, I'm wondering if large $N$ CFTs have a (quantum) phase transition as the 't Hooft coupling is varied. To be more specific -- if I look at correlation functions of ...
19
votes
5answers
2k views

What do theoretical physicists need from computer scientists?

I recently co-authored a paper (not online yet unfortunately) with some chemists that essentially provided answers to the question, "What do chemists need from computer scientists?" This included the ...
1
vote
0answers
139 views

FOV reduction with Fresnel

I have a simple optical system that works based on energy collection. (i.e. I have a photo diode that counts photons). I don't do any imaging. For my application, I need to have a specific FOV and I ...
12
votes
3answers
148 views

Visualization of 1D spin chain wave fuction

What are the known methods for visualizing quantum states of one-dimensional spin chains? They can be based either on their wave functions or density matrices. My particular interest is in plotting ...
21
votes
2answers
315 views

Post-doc advice for a low publication grad student

As a grad student, I have a single publication, a conference proceeding, to my name. So, my question is what do I need to do to obtain a post-doc position? Obviously, my references are going to be ...
0
votes
1answer
2k views

Would a generator in vacuum/space provide electricity endlessly?

At it's simplest, electricity generation is achieved by induced voltage due to a changing magnetic field. In a vacuum in the absence of friction, would the initial spin imparted to the rotor of a ...
4
votes
3answers
176 views

Fall/Winter Viewing

I live in Seattle and am thinking of purchasing a telescope. Is fall/winter a decent time of year for viewing (aside from summer)? Are there any major viewings/events during that this of year? I know ...
-1
votes
2answers
3k views

Celestron NexStar 6 SE vs. Orion XT8 [closed]

I'm interested in purchasing a new telescope and have narrowed it down to the NexStar 6 SE vs. the Orion XT8. I'd like to be able to get into astrophotography and read that having the Go-To ...
3
votes
3answers
117 views

Photographs of galaxies many light years far from the Earth

Using ground-based telescopes or the Hubble Space Telescope, astronomers take photographs of galaxies which are many light years from the Earth. Does it mean those photographs are as old as the ...
1
vote
1answer
1k views

How do Einstein’s equations support mass gain in particle accelerators? [duplicate]

Possible Duplicate: Why does the mass of an object increase when its speed approaches that of light? A charged particle that is accelerated through a particle accelerator like CERN ...
1
vote
0answers
94 views

Masses of all the particles in the Standard Theory [duplicate]

Possible Duplicate: If photons have no mass, how can they have momentum? I'm sure this question has been asked here before but I wasn't able to find it clearly answered in one q/a session. ...
5
votes
2answers
1k views

Does space have to be filled with charged particles to carry electromagnetic waves?

I'm a newbie here so have mercy. I'm studying electromagnetic waves. This is the propagation of energy via the vibration of charged particles, as I understand it. A charged particle could be like ...
5
votes
0answers
461 views

Hankel function in terms of planewaves [closed]

It is well know that planewaves are a complete basis for solutions to the wave equation. Let us assume a 2D space, and at fixed temporal frequency, the equation reduces to the Helmholtz equation. In ...
2
votes
0answers
223 views

How is the “negative dispersion” derived?

I'm looking at Kopfermann H., Ladenburg R., Nature, 122, 338-339 (1928) and it appears Ladenburg in Ladenburg R., Z.Physik, 4, 451-468 (1921) was the first to discover the phenomenon of "negative ...
4
votes
1answer
304 views

Propagators from integral representations of Green`s functions

I'm working on an article about propagators from int. representations of Green`s functions for several N-dimensional potential(all this is done in an N-dimensional Euclidian space). Potentials like ...

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