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.

learn more… | top users | synonyms

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 ...
2
votes
0answers
60 views

Continuum analogue of $ \langle \psi | \psi \rangle = \sum _i a_i^* a_i$

I'm learning Dirac notation, and I found the following exercise: Verify that if $$|\psi \rangle=\sum_i a_i |i\rangle, \tag{1}$$ (where $a_i=\langle i|\psi \rangle$), with $$\langle i|j ...
4
votes
2answers
666 views

In interferometry, what is the origin of the name “Airy function”?

In interferometry (specifically, in the domain of Fabry-Perot cavities), the function $$f(\phi) = \frac{1}{1 + F \sin^2 \phi},$$ which describes the shape of the resonant structure of the cavity, is ...
0
votes
1answer
25 views

What is the recommended symbol for Volumetric flow rate? [on hold]

I'm currently working on a paper with a mathematician. He always writes $\dot Q$ as well as $\dot V$ for volumetric flow rate and claims both are standard notations. Till now I always used $Q$ ...
1
vote
1answer
190 views

Wormholes and the illusion of time?

I was watching a video on Youtube by Brian Greene, "the illusion of time."http://www.youtube.com/watch?v=j-u1aaltiq4 In that video, he introduces to me the idea of a "brane," or a slice of the ...
-1
votes
1answer
46 views

How to invent mathematics to find solution to real world problems?(without high level mathematical knowledge) [on hold]

Let's say I want to know how waves are formed when a stone is dropped in water, how trees are deformed by the wind, etc, and I want to invent the mathematical equation to predict the behaviour of ...
4
votes
1answer
141 views

Using a laser to overhear a room conversation

Movies with science based tricks and gimmicks are generally silly and sometimes even annoying. The science based trick that I don't know enough about to judge is the following (and I have seen it in a ...
0
votes
1answer
44 views

Is it physics that leads to development of maths or is it maths that leads to the development of physics? [closed]

Like calculus(which is maths) was discovered from physics. Are there theories in which maths leads to the discovery of new physics theories? So is it physics that lead to development of maths or its ...
8
votes
1answer
397 views

Reference Request: Classical Mechanics with Symplectic Reduction

I am trying to find a supplement to appendix of Cushman & Bates' book on Global aspects of Classical Integrable Systems, that is less terse and explains mechanics with Lie groups (with dual of Lie ...
-1
votes
0answers
41 views

How did Ising pronounce his name? [closed]

The surname of Ernst Ising, of Ising model fame, is often pronounced as EYE-zing by non-German speakers, but as EE-zing by German speakers. It is frequently claimed that EE-zing is the correct ...
1
vote
2answers
241 views

Correct terminology for combined kinematic and dynamic state

The kinematic state is defined as the position and orientation in space. The dynamic state is defined as the associated velocities. What is the correct terminology for the combined kinematic and ...
4
votes
2answers
181 views

Explain the notion of light/electromagnetic waves/photons to a non-physicist

A non-physicist asked me about special relativity. My explanations naturally were based on gedankenexperiments involving light. This forced the question: "What is light? It is particles, isn't? Or is ...
-3
votes
1answer
71 views

Are time and space interchangeable? [closed]

Mass and energy are interchangeable. Does that mean time and space are interchangeable too? Reason for question: The only difference I can comprehend between matter and energy is that energy has no ...
8
votes
3answers
4k views

Why metric system uses kilogram as a basic SI unit?

SI system uses all (that I know) measurement basic units as 1 (single) instance: meter, second, ampere, etc, except the KILOgram. It already defined with 1000 multiplier (kilo). It prevents from ...
2
votes
2answers
24 views

What S means in S-duality?

As I know, there are many dualities related to S-duality. For example, Montonen-Olive duality, Seiberg duality. and so on. so, I wonder that what "S" means in the term "S-duality". If this is a stupid ...
0
votes
1answer
26 views

Formula relating sum of values of a function to its integral

I came across the above formula in some quantum mechanics lecture notes explaining the Casimir effect. Anyone seen it before if so could you please tell me its 'name'. B refers to the Bernoulli ...
0
votes
1answer
90 views

How relevant is the Heisenberg Uncertainty Principle?

I was originally surprised to see that, $$\Delta x \cdot \Delta p \gt {{\hbar} \over 2}$$ But, then I realized that $\hbar/2=5.27 \cdot 10^{-35}$. According to this other question, the smallest ...
9
votes
3answers
199 views

Why is the $dx$ right next to the integral sign in QFT literature?

I've noticed that in QFT literature, integrals are usually written as $\int \!dx ~f(x)$ instead of $\int f(x) dx$. Why?
0
votes
1answer
39 views

Can avg. Vel. be zero in uniformly accelerated straight line motion?

A particle moves in a straight line with constant acceleration. The average velocity of this particle in an interval is zero. According to me it may become possible when velocity of particle is in ...
0
votes
1answer
133 views

Are Feynman's Six Easy Lectures still relevant today?

I haven't learned anything about modern physics at the university yet, but next year I will, and in the summer before I thought I would read this book, Six easy lectures from Richard Feynman. It was ...
0
votes
1answer
60 views

Does energy exist? [closed]

None of this is going to be rigorous or have a right answer, so please don't take it as though I'm demanding one. I'm just interested in everyone's thoughts. It feels to me (and possibly you) that ...
6
votes
4answers
1k views

Misused physics analogies [closed]

Have you noticed that many questions and misconceptions in physics arise due to misuse of analogies, which were invented to "explain in simple words" some physical phenomena? For example there is a ...
0
votes
1answer
37 views

I'm interested in the use of self-similarity in physics. Is this a reputable subject? [closed]

I'm interested in fractals, self-similarity, and chaos. Many physicists disregard these phenomena as candidates to explain the fundamental properties of the universe. However, when I read about ...
0
votes
1answer
79 views

Does the randomness of QM do much in everyday life? How much? [closed]

My apologies if in its current state this question isn't squarely suited here; I've worked it until it seemed reasonably articulate. Feel free to move it if it'd be better received elsewhere. ...
1
vote
2answers
47 views

Do chemical bonds abide by widely accepted geometric principles?

To elaborate, it is mathematically proven that triangles are the strongest shape. I don't know what strong materials there are in the world but I have heard of carbon nanotubes. In the case of ...
1
vote
0answers
49 views

How does the moment problem arise in physcs? [closed]

The (finite) moment problem is stated as follows: Given an interval [a,b] and set of reals $\{ \mu_0,...\mu_N\}$ for some fixed $N$ Find real valued function $\rho:[a,b] \to \mathbb{R}$ of ...
1
vote
1answer
69 views

Meaning of the term 'bulk'

I have recently started reading literature on 2 dimensional systems in Condensed matter. While reading, I frequently came across the word 'bulk'. Sometimes it referred to 2-D and sometimes to 3-D. I ...
0
votes
0answers
39 views

What is the first topic on mathematics,that an undergraduate physics student must study? [duplicate]

I aspire to become a theoretical physicist. I like to understand about infinite series and so on. Could you please recommend me any book?
8
votes
7answers
7k views

Can a scientific theory ever be absolutely proven?

I personally cringe when people talk about scientific theories in the same way we talk about everyday theories. I was under the impression a scientific theory is similar to a mathematical proof; ...
1
vote
1answer
72 views

Can photons accelerate? [duplicate]

I was just wondering if there's a (hypothetical) situation where a photon could accelerate and what the consequences of this might be?
1
vote
1answer
50 views

Necessity, significance of Spinors

This is an area I am researching at my own pace, general rotations in 3D. I've known about the plate trick for a while as well, and have a very rough understanding of the concept of ...
-1
votes
1answer
50 views

Does this analogy with matter and energy hold? [duplicate]

Matter is to energy as dark matter is to dark energy. Is that statement correct? If not, is there any relationship, that we know of, between dark matter and dark energy? When I say there is an ...
0
votes
1answer
1k views

Natural phenomenon which inspired science? [closed]

I'm looking for a list of natural phenomenon which inspired science and technology like how bat inspired the radar concept....Any idea ? Thx for helping, Stephane
-2
votes
1answer
38 views

Spin-resolved current [closed]

What is spin-revolved current? Is it the spin current?
4
votes
1answer
129 views

How is classical information put into and retrieved from a quantum computer?

How, if you had to find the factors of say a 256 digit number, would you go about inputting the data and how do the proper answers "drop out" of a quantum computer. Other than terms such as qubits, ...
0
votes
0answers
23 views

What's the best way to avoid slipping on ice? [migrated]

Where I live, winter is still a good bit away, but last year I slipped on ice and ended up with a black eye and a broken wrist. This year I sincerely want to reduce the chances of that recurring. I ...
4
votes
2answers
46 views

Pointwise and uniform convergence. Examples from physics

I am a first-year mathematical student, and from a mathematical perspective I understand the difference between pointwise and uniform convergence of sequences and series of functions. However, I have ...
0
votes
2answers
131 views

Is the intuition of “absolute simultaneity” necessarily wrong?

I read about Einstein’s theories of relativity with all the interesting stuff like time dilation, mass increase and whatnot. And also about the relativity or conventionality of simultaneity. The ...
2
votes
2answers
98 views

What is high energy physics?

Is high energy physics the same as particle physics? Does research in high-energy physics include things like quantum gravity, string theory and quantum field theory? Is unifying the four ...
22
votes
6answers
3k views

Are there two theories that are mathematically identical but ontologically different?

I have no background in physics but there is a question that has been bothering me, so I'm asking you. Are there at least 2 physical theories that are : Mathematically identical, which means that ...
13
votes
6answers
3k views

Why do physicists believe that there exist magnetic monopoles?

One thing I've heard stated many times is that "most" or "many" physicists believe that, despite the fact that they have not been observed, there are such things as magnetic monopoles. However, I've ...
-2
votes
0answers
33 views

Subject is Maths that would complement Physics? [closed]

Suppose Math has 5 sub parts- Analysis: Analysis, Complex Analysis, Measure theory and integration,Functional Analysis Algebra: Group Theory, Vectors space-rings-modules, Galois, Algebra Number ...
5
votes
1answer
92 views

Unification of Weak and Electromagnetic forces

I'm curious how the weak and em forces relate to one another. My knowledge in this area is weak (ha) but I am interested in an explanation for how these two forces relate to one another, and how / why ...
1
vote
0answers
25 views

Prepare for HEP-th graduate application: books, research opportunities,etc [closed]

I want to specialise in high-energy physics theory. I feel quiet unconfident because the I just knew that the field is insanely competitive, so I really need your advice to guide me a bit, and any ...
8
votes
7answers
313 views

Are the results from models considered “data”?

At the AGU, I presented a poster on vocabulary for discussing data systems, and someone left a note at my poster stating: You have a bias here towards observational data. Need to recognize that a ...
2
votes
2answers
99 views

Mathematics needed for string theory [duplicate]

I'm interested in cutting edge string theory studied by research physicist. I'm wonder what mathematics is needed and how far am I in terms of mathematics background needed and how much more ...
1
vote
4answers
750 views

What exactly is meant by infinity?

What exactly is meant by infinity when I see it in a physics equation (always something wrong?)? And in experiment how many orders of magnitude can be treated as infinity (say, if infinity is ...
2
votes
0answers
47 views

Piezoelectric effects of naturally shaped quartz crystal for maximium Q?

Background Based on helpful comments and links here and also from my question on the electronics stackexchange, I have learned that the quartz crystals are nature's transducers of energy, allowing ...
0
votes
2answers
47 views

Solid Mechanics book recommendations

I'm searching for a book on Solid Mechanics that explains the topics intuitively (similar to Kline explanations on Calculus: An Intuitive and Physical Approach). Also the book should have the ...
6
votes
4answers
167 views

Is differential geometry used in solid state?

I'm an undergraduate in physics interested in a career in solid state. While I know that any additional math is helpful--I am on time constraints, and can only take a few supplemental classes. That ...