# Tagged Questions

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.

0answers
35 views

### Frozen water cooler bottle [closed]

My water bottle for my water cooler is frozen. Should I place it onto the water cooler while it is frozen, wait till it thaws a bit, or wait till it thaws completely?
1answer
45 views

### Is there a name for leptons that are not neutrinos?

Is there a name for leptons that are not neutrinos? Not sure if its exists, its not particularly easy to search for. Is there a name for the set of charged leptons (or leptons that are not neutrinos)? ...
0answers
81 views

### Why are so many relationships in physics described by equations? [closed]

Consider $f$, some mapping between two ordered subsets of the natural numbers, $A$ and $B$. I see two ways $f$ can be expressed. The first way is an equation that defines $f$ (i.e. $f(A) = 2A$). ...
2answers
88 views

### What exactly is an arbitrary parameter?

I was reading the article Turning Points: A meeting with Enrico Fermi by Freeman Dyson (available e.g. here), and I had a question about Dyson's use of the term 'arbitrary parameter'. More ...
0answers
61 views

### Why isn't $G=1$ as common as $c=\hbar=1$? [closed]

It is standard practice in theoretical physics to use a system of units in which $c=\hbar=1$. However, even though you could also set $G=1$, most physicists prefer not to. For example, in my cosmology ...
3answers
259 views

### What does “the fabric of space and time” actually mean? [closed]

I've heard the term "the fabric of space and time" in both physics and science fiction, and although I know it has something to do with general relativity, I don't understand what, specifically, they'...
1answer
61 views

### Does gravity affects on electrons in a noticeable way? [closed]

Is there a way to force a free electron move in a low speed in order to observe it actually hitting 'on the floor'?
1answer
57 views

### Is there a way to study mechanics without having to rely on free body diagrams?

For example, consider a very simple situation often used as example in teaching: a horse pulling a stone through a rope attaching them. The analysis goes something like this: There is a force ...
1answer
89 views

### Feynman's question on the mathematical machinery underlying nature [duplicate]

Physicist Richard Feynman said in his lectures "It always bothers me that according to the laws as we understand them today, it takes a computing machine an infinite number of logical ...
0answers
32 views

### Approximating Gallons of Gas Needed for Trip (read: physics grad. with too much free time)

My departure from college has left me with an itch for physics-y problems to solve, and my boredom and free time gave way to this approximation of the gallons of gas I use for the trip to my ...
3answers
256 views

### Confusion about the concept of cosmological horizon

This question was inspired by this one By definition we cannot see any event happening beyond the cosmological horizon. Let us assume that the expansion rate of the universe is such that the radius ...
0answers
22 views

### Hiccup in frequency domain

Main question: What would the Fourier transform of hiccup look like? This question is too general so let me elaborate a few possible approaches. Hiccup just as a series of pulses (of no matter what ...
1answer
264 views

### Why do astronomers call all elements heavier than helium “metals”?

I understand that a scientific term need not be constrained by its etymology. But is there some significant reason why astronomers choose to call all elements heavier than helium "metals"? Are ...
2answers
117 views

### Does it make sense for physics to predict the unphysical? [closed]

I hear people say things like "inside a black hole the laws of physics are not valid" or "there can be parallel universes with different physical laws" or "before the big bang there was nothing". ...
0answers
108 views

### Real world applications of post-1950s High Energy Physics [closed]

Imagine a world where people knew everything we know today except for high energy physics, where their knowledge ends at our ~1950s level. Is there any real world application, any particular piece of ...
0answers
45 views

### Sticky physics of pasta mixture [duplicate]

When you mix cooked noodles or other "prevailing 1D pasta" like spaghetti with other ingredients like olives, pieces of meat (not minced) etc. you will probably experience the fact, that the mixture ...
1answer
58 views

### Do physicists subscribe to Occam's razor? If so, how do you define 'all things being equal'? [closed]

The question here is the title: Do physicists subscribe to Occam's razor? If so, how do you define 'all things being equal'?
1answer
49 views

### How Does Rotational and Turbulent Motion Contribute to the Pressures of Dynamical Systems?

Rotational and turbulent motion can deepen a gravity well in a galaxy or galaxy cluster. In an analysis of the mass components of a large body, this would appear to be one of the components. Does it ...
0answers
30 views

### What exactly is wavefield extrapolation?

I am trying to understand what exactly wavefield extrapolation is. I can understand extrapolation of a function, 'wave' and 'field' as well; but could not understand the meaning or the problem "...
1answer
49 views

### Why did the inflation era not produce decompactification of the extra dimensions of string theory?

My question is undoubtedly naive, due to lack of background, but any answers, or simply comments with short explanations of my incorrect assumptions, would be appreciated. I must point out this ...
0answers
38 views

### Book for quantum field theory similar to Ballentine's quantum mechanics book [duplicate]

I have been studying quantum mechanics from Ballentine's book. I enjoy such books. I want somebody here to recommendation a book for qft with similar approach.
0answers
108 views

### Undergrad in QFT/GR looking to do string theory Ph.D [closed]

I am currently a third year undergrad in physics who is currently taking QFT and GR. I took these classes just out of pure interest in the subjects but I find that my mind is being blown almost every ...
4answers
196 views

### Quantum entanglement and information transfer: Does particle separation process set speed limit?

Background I recently read that a group had managed to overcome both the communication loophole and the detection loophole for Bell's theorem. In reading the article, I started to think about another ...
0answers
138 views

### Which problem is Oppenheimer working on in this picture? [closed]

Does anybody recognize the equations on the blackboard? Above his hand, with the $\gamma_k$ term and its complex conjugate, it looks like a written out matrix representation of a Hamiltonian $U$, ...
0answers
16 views

### Which are some good books to learn about quantum states? [duplicate]

I am aware of the book Geometry of Quantum states: An introduction to Quantum Entanglement by Bengtsson & Zyczkowski. I have read the book Quantum Mechanics: A Modern Development by Ballentine.
1answer
134 views

### Can someone explain this joke about the fine-structure constant and Pauli? [closed]

I was once told this joke: In Dec 1989 Physics Today ,page 9, David Gross wrote "...One of the best of the many Pauli jokes tells of Pauli's arriving in Heaven and being given, as befits a ...
1answer
110 views

### If this were possible, would it count as a modification of quantum mechanics? [closed]

This question will be re elaborated to meet the standards of this site in shot
1answer
39 views

### What are some good introductory book references on time-varying electromagnetic fields?

What are some good introductory book references on time-varying electromagnetic fields? I need a refresher on the physics background on this topic. I intend to do research in electric motor-related ...
2answers
101 views

### Textbook for mathematical Lagrangian mechanics [duplicate]

I'm looking for a textbook or online notes or a review article etc on a rigerous formulation of Lagrangian mechanics. I'm well aware of the book by Arnold but I would like something to accompany it. ...
1answer
60 views

### Naming anti-electrons and anti-protons [closed]

I think I understand why an anti-electron is called a positron (since it symbolizes positive charge) But why then is anti-proton called an anti-proton and not a negatron?
1answer
50 views

### What is an awkward constant and is there a relation to ad-hoc hypotheses?

[I'm not entirely sure whether this is the right board, since it is not a technical but a soft question]. I'm reading the textbook "Spin Dynamics - Basics of Nuclear Magnetic Resonance", 2nd ed., (...
0answers
19 views

### Resources on the discreteness of space and time

Does anyone know any books or other sources of information on the discreteness of space and time? The only ones I've managed to find require graduate level physics knowledge, which sadly I do not ...
1answer
34 views

### 5UDH Tandem electrostatic accelerator

What does UDH stands for in the name of an electrostatic accelerator 5UDH-2 Tandem accelerator? Does it is related to its working or just a trade mark?
2answers
74 views

### Hot bullets and shot cowboys [closed]

Please excuse the title of the question, there is physics involved here, but I can't think of a way of writing the title without it being more to the point of the question. A cowboy film is pure ...
1answer
79 views

### Popular books on cutting-edge physics [closed]

I watched this video, in which different types of topics are discussed like Quantum Information, Quantum Computation, Universe as hologram, Hidden information, Quantum Entanglement, Black holes and ...
1answer
135 views

### How much pure mathematics do theoretical physicists know? [closed]

I'll be precise: how much mathematics (in terms of courses in a university mathematics department or mathematics textbooks) can a very good theoretical physicist be expected to know? If this depends ...
1answer
75 views

### State of academic fields of analytic mechanics and Multi Body Dynamics (MBD)

My question essentially contains two parts: one practical question and one philosophical question. Background I am an engineering student working in the field of Multi Body Dynamics (MBD). My ...
1answer
314 views

### What is meant by 'probability of transition per unit time'?

Today I came across a term used by Feynman in his thirteenth lecture: 'probability per unit time' to go from $| 1\rangle$ to $|2\rangle$ while initially being at $|1\rangle$. This is the excerpt fom ...
3answers
238 views

### Should these be called “weights” or “masses”? [closed]

Yeah, those circular metal disks. Weights or masses? I call them weights because when I attach them to a spring I'm interested in their weight, but it feels odd saying a "Pick up the 100g weight". "...
1answer
109 views

### Can the Earth be seen to transit the sun from the outer planets?

Transit of Mercury as seen from Mars The Curiosity rover on the planet Mars observed the planet Mercury transiting the Sun, marking the first time a planetary transit has been observed from a ...
1answer
47 views

### Doubly magic isotopes

I understand the definition of a magic number in nuclear physics to mean a number of either protons or neutrons to completely fill a nuclear shell. I see here the term "doubly magic" used for 78Ni: ...
1answer
51 views

### Reading ensdf files

I understand that this is more of a computing question, but I still think the appropriate place to ask it is here. The Evaluated Nuclear Structure Data Files are on the internet, available for ...
1answer
119 views

### How do physicists develop theories? [closed]

I'm wondering about the way physicists develop "unified theories" and models about the universe, like string theory, or quantum mechanics. People (on this forum for example) often say things like "at ...
1answer
184 views

### Is string theory really science? [closed]

According to Karl Popper's theory of demarcation, science should be falsifiable but string theory is yet to be tested experimentally as It will require at least 19 TeV of energy to prove it which is ...
2answers
91 views

### Has Dirac ever co-authored a paper? [closed]

Just curious. Not counting PhD theses, books, and review papers, but regular research papers with original ideas.
1answer
563 views

### What is the recommended symbol for Volumetric flow rate? [closed]

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 $Q$ (...
1answer
207 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 ...
1answer
167 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 ...
2answers
94 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 ...
1answer
31 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 ...