# Questions tagged [definition]

The definition tag is used in situations where the question is either about how some term or concept is defined or where the validity of an answer depends on a subtle definition of some term or concept used in the question.

902 questions
Filter by
Sorted by
Tagged with
2answers
53 views

### Difference between left- and right-handed, helicity and chirality

What is the difference? I know there is the (almost) same question What's the difference between helicity and chirality? but when a particle is given as left-handed. Is it helicity or chirality?
1answer
241 views

### Definition of one-particle irreducible diagrams

Text books often defines one-Particle Irreducible diagram (1PI diagram) as a connected diagram which does not fall into two pieces if you cut one internal line. Is this internal line the full ...
0answers
25 views

### What do the terms “Frame specific work” and “Frame dependent work” mean? [on hold]

I was reading a paper published in A.J.Phy. American Journal of Physics 60, 356 (1992)[All About Work] by A. John Mallinckrodt and Harvey S. Leiff There I found this two terms but when tried to ...
1answer
308 views

### Mathematical definition of wavefront in case of non-harmonic waves

What is the general mathematical definition of wavefront? Wavefront is the surface where, at fixed time, the phase is constant But for non-harmonic waves we cannot talk about phase as the function ...
0answers
18 views

### What is Wedge Constraint? (Definition)

What is Wedge Constraint? How can we apply it in the following problem? The block of mass $m$ slides on a wedge of mass $m$ which is free to move on the horizontal ground. Find the accelerations ...
0answers
52 views

### What motivated Gibbs's definition of Gibbs entropy? [on hold]

What motivated Gibbs's definition of Gibbs entropy? I have read and I think that I agree with the idea that if we have to choose probability distribution for an unknown system then it is a good idea ...
1answer
142 views

### Proper definition of Internal energy

In Internal energy of a gas ($U$), we have to include ALL types of energies possible like $KE$, bond energies, nuclear interaction energies, etc.., However we have derived that $U = (f/2)nRT$ from ...
1answer
106 views

### The invariance for time-reversal: some clarifications

On the Physics.SE I haven't found a simple definition of the invariance for time-reversal. Is it possible to have a simple explanation (also using differential equations) of the invariance for time-...
2answers
5k views

### Understanding terms Twist and Wrench

In kinematics, physics and especially robotics, we often encounter the terms Twist and Wrench. Twist is (LinearVelocity, AngularVelocity) and Wrench is (Force, Torque). The reason I'm confused is I ...
1answer
65 views

2answers
57 views

### What is irrotational flow? How to judge?

For example, when the wing moves horizontally, the direction of fluid flow changes first to upward at the leading edge of the wing and then to downward at the trailing edge. Does it rotate? If the ...
1answer
36 views

### What is a pseudopure state?

In the paper titled "Experimental Implementation of the Quantum Baker’s Map" by Weinstein et al. (Phys. Rev. Let. 89 (2002)), the author says something like [...] the pseudopure state corresponding ...