Questions tagged [intuition]
86 questions
26
votes
7 answers
Can spinors be explained or understood without group or representation theory?
Vectors, either as abstract mathematical elements of a vector space (in this case the definition of the vector is divorced from any notion of transformation), or as elements of tangent spaces on manifolds (in this case the definition of the vector…
Jagerber48
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15
votes
9 answers
Why does something round roll down faster than something square?
Why does something round roll down faster than something square?
That's a question given to me by my five year old son.
So let's not get into detailed discussion about what is 'square' and what is 'round' or what is 'rolling down'.
I thought that…
Sextus Empiricus
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13
votes
4 answers
What is an Intuitive example of a Gauge Symmetry?
Can anyone give an intuitive example of what a gauge symmetry is? I am new to this concept and would like to understand it better!
13
votes
2 answers
Are chaotic systems the same as dissipative systems in inverse time?
Lyapunov exponents define whether a system expands or contracts in phase space and can be used to determine whether a dynamical system is chaotic, conservative, or dissipative. If the volume expands in at least one dimension, the system is chaotic.…
J.Galt
- 233
11
votes
2 answers
How to raise and lower indices as a physicist would handle it?
Show that Einstein's equation
$$G^{\mu\nu}=R^{\mu\nu}-\frac12\mathcal{R}g^{\mu\nu}=\frac{8\pi G}{c^4}T^{\mu\nu}\tag{1}$$
can be written in the form
$$R^{\mu\nu}=\frac{8\pi G}{c^4}\left(T^{\mu\nu}-\frac12\mathcal{T}g^{\mu\nu}\right)\tag{2}$$
where…
user256509
9
votes
5 answers
Intuition for angular momentum
A single object with mass $m$ is rotating around an origin at a distance $r$ and speed of $v$; so its angular momentum is equal to $mrv$; if we decrease its radius (say shorten the rope) its speed increases, due to conservation of angular momentum.…
7
votes
1 answer
Why do I get a different result if I flip a loop and then apply Kirchhoff's loop rule?
I've been practising to solve some exercises on electric circuits, especially using Kirchhoff's loop rule.
Here I am asked to determine the intensity of the currents passing through each of the resistors.
To solve the exercise, I have to focus on…
Davide Masi
- 259
7
votes
4 answers
$1/r^2$ force and "photon decay"
Background: My question is about the interpretation of the $1/r^2$ force in terms of the fundamental processes of the underlying QFT. We know that if the photon had mass $m$, then we may have a "massive" version of QED that is still renormalizable…
Quillo
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7
votes
8 answers
What are the dependent and independent variables in Ohm's law?
I can't quite wrap my head around Ohm's law. The relationship itself is quite intuitive to me. What I don't understand is when a system has dynamic voltages, currents, and resistances. I don't quite understand which variables are dependent and which…
Franklin V
- 191
6
votes
4 answers
Analogy for Lentz soliton
Analogy for Alcubeirre Warp Drive:
Every explanation of warp drive in layman terms has this sentence in it:
"The Warp Drive will contract space in thier front and expand space behind."
(I am not sure that this is literally what the alcubierre…
Rounak Sarkar
- 777
6
votes
8 answers
Are fundamental forces net forces being effective in straight lines?
Considering electrostatic force,a part of electromagnetic force,
When a positive point charge (fixed) and a free negative point charge are in surroundings,we observe an attraction between them. Also,the force of attraction is along the line…
GRAVITON PI
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5
votes
2 answers
How to build an intuition regarding QM angular momentum?
I am trying to build an intuition on how angular momentum algebra works.
From what I currently understand there is a set of rules we must know to deal with angular momentum:
The commutator of angular momentum components is non zero, so we can't…
Noumeno
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4
votes
1 answer
How can a scalar field have components and how do I interpret these components?
From lecture notes$^\zeta$ I've been reading that:
Consider a real three-component scalar field
$$\phi=\begin{pmatrix}\phi_1 \\\ \phi_2 \\\ \phi_3\end{pmatrix}\tag{a}$$
with…
user231296
4
votes
3 answers
Why does a distant rotating body have angular momentum about the origin?
In a frame where the center of mass is stationary, the angular momentum of a body is invariant to translation of the origin. That is: $\mathbf{L} = \sum_i \mathbf{r_i} \times \mathbf{p_i}$ is constant regardless of choice of origin so long as…
Ned Ruggeri
- 153
4
votes
1 answer
What's the intuitive physical difference between the conservations of momentum and of the boost generator in SR?
This is a soft question about classical special relativity (although a related question applies even to nonrelativistic classical mechanics).
The (connected) symmetry group of Minkowski space is the Poincare group, which is 10-dimensional and so has…
tparker
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