Questions that ask about some aspect of physics research or study which doesn't involve the actual physics. In general, soft questions can be answered without using physical reasoning.

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-6
votes
1answer
56 views

Does gravity slow entropy? [closed]

Just got to thinking about why time slows in a gravitational field. It occurred to me that, in a gravitational field, the closer you get to the source the slower time seems to travel. But also, the ...
0
votes
2answers
38 views

Is net work and total work same?

According to my text book Total Work = Delta Kinetic Energy = KEf - KEi But then work is defined to be dot product of Force (vector) and Displacement (vector). Also to my knowledge work is ...
0
votes
1answer
47 views

Algebraic properties of fundamental physical constants

A few weeks ago I started wondering if there's any reason for a given fundamental physical constant, like Boltzmann's one, to enjoy some algebraic properties, for example being rational/irrational or ...
0
votes
1answer
41 views

Superscript on density matrix

I have been asked in homework to solve the optical bloch equation for the initial condition of $\rho_{22}=0,\rho_{12}=0$. Professor gave a hint of the general equation and let us carry it from here. ...
2
votes
2answers
47 views

Is Venus in the habitale zone of a robot (transistor CMOS brain, metal body) ? Any definition by NASA?

So the robot's information-processor works based on CMOS technology, the energy is powered by lithium-ion battery/solar and the body is made of stainless steel. For reference you can think of the ...
2
votes
1answer
112 views

Learning physics from a strong math background? [closed]

I have a master's degree in operations research and took several PhD level math courses. In particular I'm most familiar with analysis/measure theory, probability theory, and stochastic processes, and ...
2
votes
4answers
98 views

Why do object appear smaller when it is further away?

This might have nothing to do with physics but why does the size of an object change when it is further away from me compared to when it is closer to me? Can someone perhaps explain this through an ...
7
votes
2answers
761 views

What is the difference between a “model” and a “theory”?

In my past questions I have used the terms "model" and "theory" interchangeably. So we have statements along the lines of The Standard Model is our best theory of particle physics but I have also ...
1
vote
1answer
60 views

Order of index in Lorentz transform

I am reading Schwartz's "QFT and the standard model". On pg 13 he gives the Lorentz transform of a rotation around the x-axis: $ \left( \begin{array}{cccc} 1 & 0 & 0 & 0 \\ 0 & 1 ...
-1
votes
2answers
57 views

What are the consequences of a non-computable universe?

I have seen that is is debated if the universe is digital, computable or non-computable. what specific consequence could this have in the format of the laws of physics? Or would that mean that we will ...
1
vote
3answers
111 views

“Complete” confusion

The word "complete" seems to be used in several distinct ways. Perhaps my confusion is as much linguistic as mathematical? A basis, by definition, spans the space; some books call this "complete" -- ...
2
votes
0answers
123 views

Why does regularization work in this Bessel function integral?

I encountered some days before an integral representation for a modified Bessel function and should differentiate it. But in this representation : $$K(\omega,a)=\int_0^{\infty} \frac{ds}{s} ...
1
vote
2answers
100 views

Why can't we precisely define physics? [closed]

While reading a textbook, I came across this statement: "A precise definition of physics is neither possible nor necessary." I was curious why it is not possible but the textbook never ...
1
vote
1answer
70 views

Quark-gluon plasma: status [closed]

Can we say that a QGP has been observed or is there only suggestive evidence? Is the idea that string theory, through the AdS/CFT correspondence, could help to understand this new state of matter ...
1
vote
1answer
90 views

Is 'Boltzon' an accepted name for particles following Maxwell-Boltzmann (MB) statistics?

In my curriculum during one of my statistical mechanics visiting lecture classes, our teacher was referring comparatively macro particles following MB statistics as "Boltzon". But I have searched ...
5
votes
3answers
444 views

Explaining a quote by Weinberg about the signifcance of symmetry groups in physics

When skimming through a book, I found this quote: The universe is an enormous direct product of representations of symmetry groups. —Steven Weinberg I am a mathematician (so I know only basic ...
4
votes
1answer
402 views

Does “finite” include zero?

Infinity, is clearly not finite. But there is some dissent on whether or not zero is finite. I have seen authors use "finite" to indicate the value of $0$ is excluded as well as infinity. Is there ...
1
vote
1answer
65 views

Understand the relation of time and the space dimensions of spacetime?

I assume the relation of the three spacial dimensions and the time dimension is handled purely in the mathematical domain, usually. But is there any intuitive description of this relationship, how ...
0
votes
0answers
100 views

Exercises with solutions in dimensional analysis - reference request

I am currently trying to brush up on my skills in dimensional analysis, and computing with units. Is there a good source of worked examples, and exercises with solutions? I'd prefer to have solutions ...
19
votes
3answers
2k views

Programming in physics [closed]

How important is programming in physics? I am studying physics at university and these first years there is actually no approach (as it is understandable) to what working in physics is like. Now, I ...
0
votes
1answer
78 views

What physical properties can we measure most accurately?

As far as I am aware, frequency is the most accurate physical property we can currently measure. This has led us to very high standards of experimental verification of e.g QED predictions and the CMB ...
1
vote
0answers
51 views

Difference between maths in physics degree and maths in a maths degree [closed]

I hope this question belongs on this site. If not, please feel free to recommend another site to move it to. Basically, I was wondering what are the main differences between the maths you learn in a ...
43
votes
6answers
4k views

What physics paper would a high school student be able to read?

I'm looking for a physics paper which a typical high school student who is new to physics would be able to read and grasp the general idea of the purpose, setup and results, if not the details. To be ...
0
votes
1answer
107 views

Laplace-Beltrami vs d'Alembert operators in flat vs curved space-time

I am confused with the difference between Laplace-Beltrami (LB) and d'Alembert operators in flat/curved space-time. d'Alembert operator in flat space-time (Minkowski) is defined as $$\Box= ...
0
votes
0answers
84 views

What is the meaning of symbols $\delta f$ and $\delta^2f$?

Professor was using these symbols to derive the continuity equation. He defined the infinitesimal mass as $\delta^2m=\rho \delta V$ and the mass that leaves some closed boundary $\partial V$ as ...
2
votes
1answer
105 views

Statistical Mechanics vs Statistics

Just how much of a representation of statistics do we get in a statistical mechanics curriculum. What are some of the useful facets of stat not in stat mech/quantum mech that physicists should really ...
3
votes
3answers
102 views

What is nuclide notation referring to? Only the nucleus or the whole atom?

sorry that this is an easy question but I am just a bit confused about nuclide notation. When you say e.g. $^{240}_{94}\text{Pu}$, are you referring to the atom of $\text{Pu}$ or only its nucleus? It ...
1
vote
2answers
55 views

What does excitation in an atom mean?

This is not regarding the definition of excitation itself. What I'm having trouble with is the difference between "electron excitation" and "atom excitation". When I electron inside the atom gets ...
1
vote
0answers
37 views

All I need to know to enter undergraduate studies in pure physics [closed]

I want to pursue pure physics after my secondary high school. I was wondering if I know all I need to know to get into this stream. So please list out all the topics I need to know before my ...
-3
votes
2answers
120 views

Using mega (=10^6) when writing by hand? [closed]

I just solved a problem which had answer 1.7*10^6 m (m=meters) If I wanted to write this using M=10^6 it would be 1.7 Mm, which if I write it by hand would look like "1.7 mm" which is confusing. Is ...
1
vote
1answer
57 views

Rain system movements and highways?

In my free time I sometimes enjoy watching the weather or radar and trying to predict how a rain system will move. Pretty often I notice that a small rain system or even a large one will congregate or ...
3
votes
0answers
53 views

Are the fundamental constants of nature independent?

Background: I am a layman and I just watched the video "Infinite Worlds: A Journey through Parallel Universes" (http://www.youtube.com/watch?v=OO4uzgiRHkE) featuring a discussion with Andrei Linde, ...
4
votes
1answer
57 views

“Hollow Earth” like Theories for pedagogical porpuses [closed]

I recently encountered the Hollow Earth theory, and I realize that This kind of theories can be used to give a really interesting discussion of a physical law. For example, If we take the ...
0
votes
0answers
30 views

Are there computerized ontologies for Relativity and (Experimental) Physics? How to contribute?

As machines and automation can generally assist humanity in physical activities, and even exceed mere human capabilities, so, increasingly, also in tasks of reasoning. A basic component of the latter ...
1
vote
2answers
91 views

Why isn't all of physics based on other rates of change [duplicate]

Define the jolt/jerk to be $$J(f)={{d^3 f} \over {dt^3}}$$ Why don't we use the concept of jolt more often considering that the change in acceleration is most definitely an important characteristic ...
0
votes
1answer
31 views

Affects of static electricity on the heart

I have an electricity problem. I get shocked by just about everything. Metal, plastic, etc. flooring can be wood,tile, carpet,linoleum , it doesn't seem to matter. The ones that go through my ...
1
vote
0answers
104 views

What does it mean: “If you scream in Hilbert space, nobody will hear you!” [closed]

This question may not be appropriate for this site and if it so, sorry for that. Today, I have heard the following quote from one of my friends: If you scream in Hilbert space, nobody will hear ...
0
votes
2answers
134 views

Naked Time ( Is there such a thing ?) [closed]

I have lately been concerned with time and whether or not it is an illusion. For argument's sake let's assume it is. Then time should stand on its own. Can anyone describe, (or point me to a paper ...
-1
votes
1answer
77 views

How do you become a theoretical physicist? [closed]

Is there a specific subject at university called "theoretical physics" or do you get a PhD in Physics and then if your job involves theory you are considered a theoretical physicist?
0
votes
1answer
65 views

What is “adjustable constant”?

This is quoted from A.P.French's Vibrations & Waves. Explicit differential form of linear harmonic oscillator is: $$ m\dfrac{d^2x}{dt^2} + kx = 0 \quad \& \quad \dfrac{1}{2} ...
7
votes
3answers
816 views

Why does the lake surface appear darker in some areas?

What causes the surface of the lake to appear darker in some places? Firstly, I know that it's not fishes that cause it. Secondly, the dark surfaces move from time to time and thus are not ...
2
votes
2answers
120 views

What unit system does Fahrenheit belong to?

Wikipedia's page for Imperial Units does not list Fahrenheit. The corresponding page for SI Units lists Kelvin as an SI unit, and Celcius as a derived SI unit. This leads me to believe that ...
2
votes
2answers
103 views

Differential operators in curvilinear coordinates

In the appendix A of Griffith's Electrodynamics text, he cites Spivak's Calculus on Manifolds as a reference more a more complete treatment of taking the gradient, curl, divergence, and Laplacian in ...
0
votes
2answers
82 views

What does a unit like $C^{1/5}$ or $kg^{1/2}$ physically mean?

I'm more of a math guy than a physics guy so bear with me.... In fractal geometry, fractals are considered to have fractional dimension. For instance an object such as the Koch curve has a fractal ...
2
votes
2answers
115 views

How are weights and scales used by the public calibrated?

My physics teacher has a set of masses: things from 1 to 10 grams. My chemistry teacher has electronic balances that measures things in grams. In France, there is a block of metal we hope no one ...
1
vote
1answer
125 views

When was the first time that superconducting quasiparticles were called Majorana fermions?

Since a number of years, the field of superconductivity has a growing obsession with Majorana fermions. I wonder how far back we can go: When was the first time that superconducting quasiparticles ...
1
vote
0answers
89 views

What is the next step in math education after taking the last undergrad math course? [closed]

Currently I successfully completed the 3rd semester of my B.Sc. in Physics. Since the upcoming summer semester is starting soon and I'm going to have some spare time I can spend, I want to expand and ...
1
vote
2answers
122 views

What does the “T” stand for in T-duality?

First of all, I am not a physicist. I'm a graduate math student and recently I came across the concept of T-duality. Actually I'm studying generalized complex geometry, which according to this paper ...
0
votes
2answers
135 views

Help with high school physics [duplicate]

I am studying high school physics and it seems i have memorize the equation and use it mechanically in doing question and memorize lots of physical phenomena.I know a lot of physical phenomena can be ...
2
votes
1answer
270 views

What was Feynman's famous formula?

In Welton(1983), Memories of Feynman, Welton mentions two formulas which he denotes as Feynman's Famous Formula (FFF) and FFF #2. Which famous formulas is he talking about? Is he maybe talking about ...