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.

0
votes
0answers
15 views

What is meant by cubic symmetry with regard to thin films growth?

I am reading a paper on epitaxial thin film growth of an alloy and it mentions that for one conditions the films grow with a cubic symmetry and for another they have an in-plane anisotropy. I would ...
1
vote
1answer
55 views

Exact meaning of 'degree'

I wish to know if there is an exact meaning of degree in physics/math/chemistry. It is used in many cases and it is not clear to me which requirements must have an unit of measurements for carrying ...
-2
votes
1answer
29 views

Specific term for a retractable lightsaber [on hold]

Okay so I know the title is a little weird, however, me and my former Chemistey teacher were talking and I was showing him a collapsible sword I printed and he said there was another name for the ...
0
votes
1answer
65 views

Why is the “fine structure” correction called that way?

I'm working on the fine structure correction to the Hydrogen atom. I have more of a conceptal, maybe historical question, why is this correction called this way? and why is the fine structure constant ...
1
vote
2answers
41 views

Do the terms “damping constant” and “damping coefficient” have standard uses?

I've heard the terms "damping constant" and "damping coefficient" used to describe both the $c$ from the viscous damping force equation $F = -c\dot{x}$ and the $\gamma$ from the definition $\gamma = \...
0
votes
1answer
48 views

Why do terms in a field theory Lagrangian that are polynomial in the fields collectively called the “potential”?

Field theory Lagrangians are often of the form of a kinetic term plus a source term minus a potential term. How do we know that the potential term is a polynomial in the fields? On a related note why ...
0
votes
1answer
35 views

Difference between Postulate versus Law

In quantum mechanic, we have many different postulates. In classic mechanic, we have different laws. As long as I know that physics's laws are temporarily correct until an anomaly. But what is the ...
2
votes
1answer
21 views

Binding energy of a molecular ion?

The protons in the $\text{H}_2^{+}$ molecular ion are $0.106 \, \mathrm{nm}$ apart, and the binding energy of $\text{H}_2^{+}$ is $2.65\,\mathrm{eV} .$ What negative charge must be placed halfway ...
-1
votes
0answers
56 views

What is the rate of change of speed called? [duplicate]

Magnitude of acceleration is definitely not the answer in case of rate of change of speed unless it it is moving in a straight path. So is there any name for rate of change of speed?
1
vote
1answer
28 views

Young's double slit experiment - fringe width [closed]

What is the main difference between fringe width and fringe breadth?
0
votes
1answer
35 views

What is proper name for non-inertial forces in GR?

General relativity works in all reference frames, so inertial forces are real in it. And due to the equivalence principle, gravity should be also considered inertial. So what is a good term for the ...
0
votes
2answers
42 views

Can displacement be negative after calculation?

Regardless of the positive or negative, doesn't the number determine the total displacement and not the sign in front of the numbers?
6
votes
3answers
2k views

What is the meaning of “matter” in physics?

What is the meaning of matter in physics? By defining matter in terms of mass and mass in terms of matter in physics, are we not forming circular definitions? Please give a meaning of "matter" in ...
7
votes
1answer
162 views
+200

Is the term “quantum triviality” defined by the UV or the IR behavior of the RG flow?

The Wikipedia page on quantum triviality seems to give two different definitions for the term that are not obviously equivalent. Some parts of the page seem to define a renormalizable theory as "...
4
votes
4answers
321 views

Is there a scalar acceleration?

Distance is paired with Displacement and it seems to be a bigger idea than just the magnitude of Displacement. Speed is paired with Velocity. I have always thought that there is not such pairing with ...
0
votes
1answer
37 views

Rotational motion and Circular motion

What is the difference between rotational motion and circular motion? Are they same or they different?
1
vote
0answers
61 views

Difference between Critical and orbital velocity

What is the difference between orbital and critical velocity of satallite ? I have read that critical velocity is constant value and it does not depend upon altitude. It only gives the velocity of ...
0
votes
1answer
88 views

Why are there lots of definitions for strain?

Why do we need Green or Almansi strains and what is True strain? I'm so confused about terminology.
0
votes
0answers
48 views

Is Universal Law of Gravitation a 'law'? [duplicate]

My textbook mentions that the universal law of gravitation cannot be proved. If so, then why is it called a 'law' and not a 'hypothesis'?
3
votes
1answer
65 views

What Does Up-Down Asymmetry Mean?

There is strong experimental evidence (reported on in the linked paper), from more than one high energy physics experiment, that up-down asymmetry is present in the decays of certain charmed baryons. ...
0
votes
0answers
72 views

How is this fluid motion called in English?

I am considering unsteady two-dimensional potential flow of ideal fluid. In the absence of active forces fluid motion is governed by equation $$ \rho \frac{d \vec{v}}{d t} = - \nabla p $$ where $\rho$ ...
1
vote
0answers
23 views

Is there a better name for flavour of particles apart from generation number? [closed]

If we assume the standard model falls into 3 generations ordered by mass. (This needn't necessarily be true.) We call these "generation 1", "generation 2" and "generation 3". So the property of a ...
0
votes
1answer
37 views

Terminology: can I use the world “comoving” to describe a reference frame in which a certain object is at rest?

Here a question about terminology. Suppose I have a particle that is moving at velocity $\beta$ in the observer (or laboratory) frame. Now, is it appropriate / legitimate to describe the frame in ...
0
votes
0answers
21 views

Branch of Physics that Examines Atoms Relationships

Is there a specific branch of physics that can examine and calculate the strengths of atomic or molecular bonds and predict how they are going to break, putting into consideration the surrounding ...
1
vote
1answer
40 views

How to understand the kernel as a transition amplitude?

Consider the time evolution operator $U(t_f, t_i)$ that controls the evolution of a wave function according to $|\psi(t_f \rangle = U(t_f, t_i) | \psi(t_i) \rangle$. As I understand it, the Born ...
0
votes
0answers
23 views

When talking about the rolling of an object (such as a wheel) what is the difference between sliding and slipping?

My question is rather simple. Concerning with the rolling motion, what is the difference between slide and slip?
0
votes
1answer
49 views

Confusion on Centigrade/Celsius Scale

There came the centigrade scale. The issue was that many solid/liquid thermometric substances didn't respond to temperature linearly so different thermometers produced different results. This was ...
1
vote
1answer
57 views

Terminology: Infrared and Ultraviolet

I am new to high energy physics and string theory. I keep reading the terms infrared and ultraviolet in papers. I assume they aren't talking about electromagnetic radiation. For example, one paper ...
1
vote
1answer
48 views

“Pure” Yang-Mills and the absence of light matter

I am researching various models of Neutral Naturalness which involve the addition of an additional gauge group whose matter content is uncharged under SM color. Many of these theories state that their ...
0
votes
1answer
23 views

Do even modes exist for e.g. pipes closed at one end?

This is really a question about terminology, The wavelength of a standing wave in a e.g. pipe closed at one end and open at the other is said to be $\frac{4L}{n}$, where $L$ is its length and $n$ is ...
1
vote
0answers
59 views

Why optical phonons are called “optical”? [duplicate]

In diatomic lattice vibration, acoustical phonons correspond to vibration. But I could not understand the relevance of term optical in this context.
1
vote
3answers
151 views

Why do we say that a photon is a particle if it is massless?

If light is made of photon particles and the photon doesn't have any mass but it is a form of energy (according to my thinking) then why do we call photons particles?
3
votes
2answers
145 views

Why is the ground state of a particle in a box called $n=1$?

For a quantum harmonic oscillator, the ground state in most sources is referred to as $n=0,$ and this state has zero nodes. For a particle in a box, the ground state in most sources is called $n = 1.$...
2
votes
1answer
69 views

Is a bound state a stationary state?

In Shankar's discussion on the 1D infinite square well in Principles of Quantum Mechanics (2nd edition), he made the following statement: Now $\langle P \rangle = 0$ in any bound state for the ...
0
votes
0answers
42 views

Name of real-valued representation of density matrix?

This is a specialization of my question https://math.stackexchange.com/q/3157300/ on math.SE. There are many ways to write the density matrix $\hat \rho$ as vector $\vec \rho$. In the Liouville space,...
1
vote
2answers
68 views

Nature of motion between comoving observers; What is the common time that they agree on?

This is a set of follow-up questions regarding this post. The following four queries are very closely related and needed to asked at the same place. Question 1 Is it really possible to regard the ...
0
votes
2answers
55 views

Name of the matrix that appears in matrix form of Hamilton's equations of motion

Consider a harmonic oscillator described by the second order differential equation $$\ddot{\phi} + \omega_0^2 \phi = 0 \, .$$ Defining $v \equiv \dot \phi$ we get two simultaneous equations \begin{...
3
votes
1answer
61 views

What is topological material?

Recently, topological material has been a hot topic in condensed matter physics, but I don't know what is topological material and how to distinguish topological material from band diagram. And how ...
0
votes
3answers
84 views

Summing up very basic terms in basic electricity [closed]

My attempt to define following terms as per my understanding. I am currently at high school. Electromotive force (EMF): Potential between two terminals when open circuited. Wikipedia's ...
0
votes
1answer
42 views

What is the difference between Closed and Bounded surface?

When I was going through "The Feynman's Lecture on physics" Volume-2 , I found the line "It is useful to speak of the flux not only through a completely closed surface, but through any bounded ...
2
votes
2answers
46 views

Ought we say 'body mass', rather than 'body weight'?

I'm asking in the context of medicine, where you're "massed" (or is it "weighted"?) on a scale. This answer beneath insinuates that 'mass' may be the preferred term, but it doesn't outwardly clarify ...
0
votes
0answers
58 views

What do we mean by curly braces in an atomic configuration?

What do the '{` mean in atomic configurations e.g: 1s(2)2s(1)2p(2){3P}3p(1) 1s(2)2s(2)2p(3){4S}3p(1)
3
votes
1answer
170 views

What's the difference between linearly polarised and plane-polarised waves?

To explain polarisation, my book gives an example of a transverse wave in a string, and explains as: Since each point on the string moves on a straight line, the wave is also referred to as a ...
0
votes
2answers
98 views

Newton's Second Law of Motion - Net Force Vs. Velocity

I am wondering about a question regarding Newton's Second Law of Motion. For an object to have a constant velocity, it means the total net force is 0 since there is no acceleration. Does that mean ...
1
vote
1answer
80 views

What's the difference between a generating function and a generator?

Usually in physics we use the notion generator to describe the infinitesimal elements associated with any finite Lie group transformation. But in the context of the Hamiltonian formalism, all authors ...
2
votes
1answer
62 views

Different Schwinger-Dyson Equations

In the literature on QFT there are a lot of different equations that are all called "Schwinger-Dyson equation" so I wanted to know how are they related and if they have proper names. The first ...
-1
votes
2answers
59 views

Is there a name for the un-integrated Lagrangian?

The "action" is a functional of fields and their derivatives integrated over a space-time volume. A Lagrangian is just integrated over the space dimensions. But what is the name of the thing to be ...
3
votes
1answer
89 views

What is energy in quantum mechanics?

Is it wrong to say energy is the expectation value of Hamiltonian? Or should I say energy is the eigenvalue of Hamiltonian?
2
votes
2answers
109 views

What's the name of the symmetry $ L \to L + \frac{d \Lambda}{dt}$?

In the Lagrangian formulation of Classical Mechanics, we have the freedom to add a total time derivative of an arbitrary function $\Lambda$ to the Lagrangian: $$ L \to L + \frac{d \Lambda}{dt} . $$ ...
2
votes
1answer
39 views

What is the relation between incompressible flow and laminar flow?

I have a small question about dynamics. My textbook shows me the velocity profile for an incompressible flow, which has a parabolic profile. Does this automatically mean it's laminar flow? I don't ...