Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [terminology]

Use this for questions relating to the proper use of physics terminology or nomenclature.

2
votes
1answer
105 views

Confused about micro, macro, ensemble, accessible, possible ect. states

I'm hopelessly confused about accessability of microstates and macrostate. Let's imagine ideal gas box, A, with parameters: $T_\mathrm{A}$ (temperature) $P_\mathrm{A}$(pressure), $V_\mathrm{A}$(...
0
votes
0answers
333 views

Local and Non-Local Potentials

Can anybody explain the difference and concepts between local and non-local potentials in light of quantum mechanics?
1
vote
1answer
77 views

The term “Configuration” in quantum field theory, what does it mean?

I would like a thorough explanation of what the word “configuration”, means, as used in ‘Quantum Field Theory’. I have seen the word used in various phrases, such as “the field configuration φ(x)”, “...
2
votes
1answer
95 views

Equivalence between ghosts?

Ok. I'm trying to get the terminology right about the term ghost in physics. Is there any equivalence between these terms? Faddeev-Popov ghosts Paul-Villars ghosts Landau ghost The vanishing ...
1
vote
0answers
61 views

What is meant by “Almost orthogonal”?

Figuratively speaking, when two quantum objects’ states are ‘almost orthogonal’, are they in some physical sense ‘almost blind’ to one another?
0
votes
1answer
31 views

What is the difference between functionalisation and passivation?

I know the basic principle of functionalisation and passivation is to add Ligands to the surface of nano particles which can limit the growth of nano-crystals in fabrication and improve proprieties ...
0
votes
1answer
378 views

Finite size effect

What does finite size effect mean in physics? I googled it and that is what I got: "When studying any macroscopic system with a very large number of degrees of freedom, invariably make an ...
1
vote
1answer
70 views

Acoustic, optical, ferromagnetic and antiferromagnetic spin-waves?

In the context of spin-waves I have seen the following words as descriptors*: Acoustic Optical Ferromagnetic Antiferromagnetic which I have seen used together e.g. "acoustic ferromagnetic spin ...
1
vote
1answer
169 views

What do the symbols $⊕$ and $⊗$ mean?

Please have a look at this presentation on Young tableaux, I'm trying to understand the signs I mention there - what do the $\otimes$ and $\oplus$ symbols mean?
0
votes
0answers
70 views

Is Potentiometer a variable resistor or a measuring instrument?

I have used Potentiometers many times, and what I understood is that it is a variable resistor. However, my Physics teacher says that he is SURE a potentiometer is used to measure stuff, and is NOT a ...
1
vote
2answers
68 views

Formal Term for an invariant constant to all observers

I was thinking of the speed of light and realized I don't know how to quickly name the concept of "physical quantity that is measured to be the same in all reference frames". Are there examples of ...
-1
votes
1answer
64 views

Is there a name for a function or field of position and rotation?

A scalar field is a function which has a different value at all positions e.g. $\phi(x)$ where $x$ is a 3-vector. Imagine that the value of a field depended not only on the position of a detector but ...
2
votes
1answer
66 views

What is the scope of the term 'orbits'?

Warning - this is a very soft question. I was wondering what the precise meaning of the word orbit is? Wikipedia refers to it only in the sense of gravitational forces, in which case mathematically ...
2
votes
1answer
108 views

Covariant Formulation of E&M

Can anybody explain me what does mean the "covariant formulation of electrodynamics"? What does the covariant here mean? Invariance of Maxwell equations under Lorentz Transformations? In what way? ...
0
votes
0answers
70 views

What does zero in zero point energy refers to?

I know due to Heisenberg uncertainty principle even empty space can have lots of particles constantly popping in and out of existence, this also means that absolute zero cannot exist but what does ...
3
votes
1answer
70 views

Constants of Integration In Hamilton-Jacobi theory

I have had this confusion for a while now. We solve the Hamilton Jacobi equation, $$H+\frac{\partial S}{\partial t}=0$$ Say we get a solution $S(q,\alpha,t)$ where $\alpha$ is a constant of ...
2
votes
1answer
96 views

What is the meaning of “inverse problems in vibration”? [closed]

I am asking you to tell me or give me a link which I can understand the meaning of inverse problems in vibration. As it is my first experience in facing the Inverse method please give me a hand as ...
1
vote
1answer
135 views

Why Hydrogen bomb is called “Thermonuclear Bomb”?

Why do we call Hydrogen bomb as "Thermonuclear Bomb" ?
2
votes
2answers
746 views

What does the term “inversion symmetric” mean?

I've read the responses to the question `"Lack of inversion symmetry" in crystal?' but I'm still unsure about the meaning of inversion symmetry. Which of the following two dimensional ...
1
vote
0answers
41 views

Representations of a symmetry group: what is actually being represented? [duplicate]

For definiteness, consider the group $SO(3)$. There is a Lie algebra $so(3)$ given by $$ [T_a, T_b] = if_{abc}T_c $$ The generators of this algebra can be exponentiated to form the elements of $SO(3)...
2
votes
1answer
59 views

What is the scope of the term 'normalisation'?

When we 'normalise' the wavefunction we put in an appropriate coefficient so that the wavefunction can act as a probability distribution. However, when I considered the eignefunctions of the momentum ...
2
votes
2answers
116 views

What is a basic physics general definition of a 'potential'?

From the Wikipedia: In physics, a potential may refer to the scalar potential or to the vector potential. In either case, it is a field defined in space, from which many important physical ...
0
votes
0answers
2k views

What is the difference between Non-harmonic oscillation, Anharmonic oscillation and Complex harmonic oscillation?

I am just wondering if the words Non-harmonic oscillation, Anharmonic oscillation and Complex harmonic oscillation mean the same thing. If not what exactly is the difference between them? Since the ...
1
vote
1answer
94 views

Difference between a “mode” and a “state” in quantum mechanics?

I am studying the book Introductory Quantum Optics by Gerry & Knight at the moment and as a reader, I stumble upon their seemingly interchangable use of the tems "mode" and "state". As far as I ...
0
votes
2answers
383 views

What does isotropic space mean?

The unit vector r shows that Coulomb's force is parallel to the line joining the charges. It could not be otherwise unless space itself has some built in directional property, for with two point ...
2
votes
2answers
76 views

The term 'anisotropic' in the context of fluid flow

The isotropy definition in Wikipedia is uniformity in all orientations; it is derived from the Greek isos (ἴσος, "equal") and tropos (τρόπος, "way"). Precise definitions depend on the subject area. ...
2
votes
1answer
161 views

What's the meaning of canonical and phantom scalar field?

I read in some paper about non-minimal derivative coupling that $\varepsilon = +1$ correspond to canonical scalar field, while $\varepsilon = -1$ corresponds to phantom scalar field. $\varepsilon$ is ...
1
vote
2answers
191 views

Does Lorentz force only refer to the force described by the Lorentz Law?

I'm sorry for my very stupid question. I'd really appreciate some help. I'm just rather confused on what the Lorentz force actually is. So my question is, simply put - what is the Lorentz force? ...
-1
votes
2answers
83 views

Is there any thought experiment that has proof? [closed]

Is there any thought experiments that are proved mathematically? Or is it thought experiments are all pure hypothesis?
2
votes
1answer
55 views

The condition for cosmic acceleration

I'm currently writing a review paper on the accelerated expansion of the universe (focussing on scalar field models like quintessence) and was wondering if there is a specific name for the ...
1
vote
1answer
44 views

Goldstone modes $\hat a^\dagger(k) \left|0\right>$ for small $k$ or $\hat a^\dagger(0) \left|0\right>$

Consider the Hamiltonian: $$H=\sum_{\vec k} \varepsilon (\vec k)a_{\vec k}^\dagger a_{\vec k}$$ with $\varepsilon(\vec k) \rightarrow 0$ as $|\vec k|\rightarrow 0$. I know that this has gapless ...
0
votes
3answers
115 views

Why did Newton introduced inertial and gravitational mass in the first place?

This might be a silly question but I really don't understand what was the reason for which Newton ended up differentiating mass into inertial and gravitational. Why did he think it necessary to do so? ...
1
vote
1answer
658 views

What is the difference between Maxwell distribution and Boltzmann distribution?

I am learning Physical Chemistry now. And on the print professor uploaded was a sentence "Compare Maxwell distribution with the Boltzmann distribution" What I know is only -mv^2/kT is written in ...
0
votes
2answers
81 views

What is the name of $(ωt+\varphi)$ in sine wave?

For a sine wave $x=A\sin(ωt+\varphi)$, $A$ is the amplitude $\omega$ is the frequency $\varphi$ is the phase What is $(ωt+\varphi)$ called? "Angle"? I can't find any source call that part.
3
votes
1answer
355 views

Why these null coordinates are sometimes called “time”?

In Minkowski spacetime, if we introduce spherical coordinates the metric becomes $$\eta = dt^2-dr^2-r^2d\Omega^2$$ with $d\Omega^2$ the $S^2$ round metric. It is then common to introduce $$u = t-r,\...
1
vote
1answer
85 views

What motivates the term “State function”?

What motivates the term "State function"? Or,in other terms, what is the relation between, potential theory, gradient fields and exact and inexact differentials?
1
vote
1answer
98 views

Has the definition of “statistical mechanics” changed from its original meaning?

I guess this never registered with me when I read the Feynman Lectures on Physics in the past. But I have wondered, from time to time, what distinguishes statistical mechanics from, say, kinetic ...
1
vote
2answers
163 views

Definition of a tensor

I think a tensor of rank $m$ on an $n$-dimensional space $V$ is a multilinear map $T : V^n \to \mathbb{R}$. For example a tensor of rank $3$ is a multilinear map $T:V^3 \to \mathbb{R}$. If $\{\textbf{...
2
votes
2answers
410 views

Extreme confusion with the metric tensors

I am extremely confused with the metric tensors. In my previous question, I figured out that tensors are "objective" entities that are independent of coordinate systems. However, metric tensors keep ...
3
votes
7answers
264 views

If we know spin isn't actually rotation, why do we still speak of intrinsic angular momentum? [duplicate]

The spin of an electron was classically thought of a spinning ball of charge. We know that that is not the case in the quantum picture, as the electron is pointlike. So why, then, do we still ...
3
votes
1answer
237 views

Clarifying and simplifying what 'mode' means in terms of SHM

I am dealing with a string-coupled pendulum, where two pendulum are tied onto one string as seen in image 1. (Image attributed to Young-ki Cho available from pre-view at DeepDyve) The symmetrical ...
31
votes
3answers
3k views

What is a “decade” as a unit of measure (ex. a decade of the EM spectrum)?

Reading through papers and online sources about radio galaxies, I kept stumbling across a term--a "decade" of the electromagnetic spectrum. Radio galaxy emission encompasses "11 decades of the EM ...
0
votes
1answer
41 views

What is the verb for what iron does to a magnetic field? [closed]

Iron, or other materials, can be used as the core of an electromagnet, to get a stronger field. What verb describes what the iron does? I'm tempted to say that it conducts the field, but I know that'...
0
votes
1answer
1k views

What is meant by a uniform body and continuous body in physics? [closed]

Is uniform mass and continuous mass is same as uniform body and continuous body? Examples of uniform, non-uniform, continuous and non-continuous mass/bodies? Please also explain a little bit. while ...
0
votes
2answers
42 views

Quantum Communication - Tx/Rx terminolgy?

When talking about Quantum Communication vs. Classical Communication data is passed via quantum entanglement; data doesn't traverse the space between the involved particles. Is one particle "...
0
votes
2answers
266 views

What's the relationship between probability amplitudes and amplitudes of a wave?

Amplitudes or probability amplitudes are the complex coefficients of the linear combination of states which represent other quantum physical states. The amplitude of a wave can be interpreted as a "...
5
votes
1answer
212 views

Why is chemical potential equivalent to a true potential?

My K&K thermal physics testbook says chemical potential is equivalent to a true potential: the chemical potential is equivalent to a true potential energy: the difference in chemical potential ...
0
votes
0answers
31 views

General solutions of the fields in a charge free system

In Electrodynamics, What do we mean by general solutions of the fields in a charge free system?
0
votes
1answer
113 views

Is there a term for the first moment of mass?

If a stationary object has a rest-mass of say $2.0$kg and is located a distance $3.0$m from a particular point (of which it is stationary relative to). Is there some term to describe the moment of it'...
0
votes
1answer
51 views

Thermal stability of solar cells

Concerning the construction of solar cells which property is referred to when researchers speak about thermal stability of solar cells?