Questions tagged [terminology]

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

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11
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481 views

Who invented the term “Coulomb logarithm”?

Who is the author of the term "Coulomb logarithm"? In fact, Coulomb logarithm was computed by Langmuir in his paper of 1928 where the term "plasma" was introduced into physics, but the term "Coulomb ...
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448 views

What is a “fiduciary” quantum state?

In Giovanetti et al.'s paper "Quantum Random Access Memory" (arXiv:0708.1879) they state: If the qutrit is initially in the $|wait\rangle$ state, the unitary swaps the state of the qubit in the two ...
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260 views

Physical interpretation: weighted eigenvalues of the Laplacian with a potential

I'm a mathematician with only the basic knowledge of Physics, so my question may be trivial: in this case, mercy me. :-) Let $\Omega \subseteq \mathbb{R}^N$ be a domain and let $V,m:\Omega \to \...
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1answer
66 views

What does the term 'high voltage' really mean?

This might be a dumb question but i am not so familiar with the word voltage: What does the textbooks really mean when they say high voltage?. Does that mean: There are more charges so more voltage, ...
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90 views

When was the phrase “beta function” of renormalization first used?

My question is a historical one: when was the phrase "beta function", as it pertains to the renormalization-group equations, used in physics? I am talking about this beta function: $$\beta_g\equiv \...
4
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2answers
977 views

Variables in calculation of drag coefficient

Okay, so I looked up drag force equation, and I found that the equation involved the drag coefficient. Then I looked up the drag coefficient, and the equation for it involved the drag force. ...
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1k views

What is the difference between selection efficiency and acceptance in high energy physics?

Often in papers the product of these two quantities is mentioned, but I'm not sure what exactly they mean separately. My guess would be that one of these is the fraction of the events that you are ...
4
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154 views

Is the phrase “coupling constant” interchangable with “ strength of interactions”?

Can I use the terms coupling constant and strength of interactions, interchangeably, or are there more subtleties to the term coupling constant that I am not aware of? Coupling Constants from ...
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1k views

What is a Fermi arc?

What is meant with a Fermi arc in the context of Weyl semimetals? Is this the just a one-dimensional Fermi surface? For example, in electron-doped graphene, the Fermi surface consists of 2 disjoint ...
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2answers
2k views

What is atmospheric stratification?

In the context of atmospheric stability, what are the meanings of stable or unstable stratification? What is stratification?
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1answer
75 views

Mathematical term for the on/off gradient functions in MRI imaging

The slice selection gradients, as well as the phase and frequency, in MRI imaging are traditionally represented by on/off box or rectangular symbols: or My question is what is the mathematical name ...
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113 views

Mean Field Theory neglects what flucutations?

This is a topic that has being confusing me for a while. A general phrase that is used in the literature is that: Mean Field theories neglect fluctuations My questions is what is meant by ...
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138 views

Terminology for a thermodynamic process in which no work is done

Is there an accepted term to be used when the work done in a process is zero? Fermi, in his book on thermodynamics seems to use "isochoric" even when the work is different from pressure-volume work, ...
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1answer
1k views

What is a Witten diagram?

Recently I heard the terminology of Witten diagram. Studying QFT, I frequently see Feynman diagrams and use them to compute scattering amplitudes, one-loop corrections and so on. In string theory ...
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112 views

What is $\mathrm{U(1)}$ vector and axial?

In hadron physics we talked about $\mathrm{U(1)_V}$ (vector) and $\mathrm{U(1)_A}$ (axial) as well as $\mathrm{SU(3)_L}$ (left) and $\mathrm{SU(3)_R}$ (right). There are certain relations between them ...
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151 views

How can we count 17 particles in the standard model

This may be a bit of numerology, but I'd like to be able to make a statement like "There are 17 particles in the standard model" with some logical definition of a particle. But this statement is ...
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160 views

If the field concept was invented by Faraday, then how did Newton interpret the $g$?

This is Newton's law of universal gravitation. $F=G\frac{m_1.m_2}{r^2}$ Gravitational field $g$ is derived from this formula $g=G\frac{m_1}{r^2}$ This is named gravitational "field" strength. If ...
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101 views

What does unfolding of attractor mean?

What does unfolding of attractor mean? Effect of time scales on the unfolding of neural attractors paper talks about Takens embedding theorum. It says that the embedding dimension should be large ...
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362 views

Effective Field Theories of QCD

Recently, I am studying the online course Effective Field Theory provided by MIT OCW. Prof. Stewart gives a nice picture to summarize the effective theories: As a newbie in this field (I only have a ...
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146 views

What does the term 'a uniform RVB spin-liquid state' mean?

I encountered this term a uniform RVB spin-liquid state in some articles, for example, see the paragraph under Eq.(29) on page 9 in this paper. What does the word 'uniform ' mean? Simply from the ...
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568 views

Why supra-conductivity became super-conductivity?

The original article by the Kamerlingh Onnes team in Leiden does not give a name to the new effect: Kamerlingh Onnes, H. Further experiments with liquid helium. C. On the change of electric ...
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170 views

How to name different approaches to relativistic quantum theory

In the introductory chapter of the QFT book by Mark Srednicki the author notes that [p. 26] So now we have two different approaches to relativistic quantum theory [...] Which [one of those two] we ...
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63 views

What name would you give to the method of approximating an arbitrary magnet with many smaller dipoles?

Let's say I had an arbitrarily shaped permanent magnet, with total magnetic moment $M_{0}$. Ways to calculate the magnetic field of this magnet include an analytic solution (if one exists), as well ...
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Can an affine first-order polynomial system be chaotic?

While studying chaos theory, one of the basic principles presented to me was that chaos only occurs in deterministic nonlinear systems. This pointed me to learn more about the differences between ...
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2answers
93 views

Differences between “cold” and “collisionless” plasma

I'm just stepping for the first time into plasma physics and I'm studying on Chen's "Introduction to plasma physics" and on the notes of professor Richard Fitzpatrick. I just seem to not have clear ...
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1answer
38 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 ...
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2answers
74 views

What are pre collisions and post collisions in forces and momentum?

What are pre collision and post collision exactly? I assume it is before collision and after collision. I can not find an answer on google.
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101 views

Mean field critical exponents and the Gaussian approximation?

A while a go I asked this question on the difference between mean field theory and the Gaussian approximation. This question is related to that. The mean field critical exponents for the Ising model ...
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144 views

What are disordered superconductors? What kind of research is done in this area?

I was talking with a friend of mine and he mentioned that his professor does research on disordered superconductivity. I had a rough idea of what superconductivity is, but when I looked up the term "...
2
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1answer
457 views

What is zero-order transmission spectrum?

In the paper The extraordinary optical transmission through subwavelength hole arrays by T. W. Ebbesen it is shown at particular wavelength there is a peak observed in zero order transmission spectrum....
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119 views

The Ising approximation - what exactly is it?

I am slightly confused about the nature of the Ising model to study ferromagnetism. Consider the Heisenberg Hamiltonian with Zeeman term: \[H=-\frac{1}{2} \sum_{i\ne j}J_{ij} S_i\cdot S_j+g\mu_B {B}\...
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488 views

Relation between inertia tensor and moment of inertia about an axis

As far as I understood, we define two quantities: Inertia Tensor - a $3\times3$ matrix, which describes the object "mass" of rotation in relation to a certain point, helping us calculating rotations ...
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137 views

Configuration space of a classical gauge theory: Physics vs. Mathematics

Let's have a look on a gauge theory on a trivial fiber bundle, as it is seen by mathematicians: We have a trivial vector bundle $(E, \pi, M; V)$ with group structure. We denote the sections of $E$ by ...
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78 views

Correct terminology or way to refer to the 2 “types” of ice sublimation

I'm trying to get the right terminology for various forms of phase change. I am familiar with the phase change / triple point diagram for water, and we have various terms for the transition of a ...
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242 views

What is the general definition of a quench?

I've seen the term "quench" used in many different contexts. It's easy to understand the meaning when the context has a simple physical analogue, such as lowering the temperature of a system to cause ...
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39 views

What is the name of the basis that uses objects of definite parity?

Currents to which gauge fields couple in four dimensions can be described as follows: $$ \mathcal{L} = -g A_\mu J^\mu. $$ Sometimes it useful to discuss these couplings in the chiral basis, $J_\text{...
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75 views

Terminology - optical (visual) properties of a structure

I am trying to understand few terminological problems that I encounter. Without knowing keywords it is hard to perform search for literature or publications in the area. The area relates to the ...
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115 views

QFT: What does “finiteness” mean?

As above: what is the definition of a QFT to be "finite"? That all UV corrections are finite and there are no divergences at all? That there are divergences, but these divergences can be absorbed in ...
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134 views

Why are Lagrangian subspaces called 'Lagrangian'?

I am wondering what the special role of Lagrangian subspaces (or submanifolds) are in mechanics. Do these subspaces have some sort of special property for which we have some sort of `Lagrangian ...
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198 views

Morphisms between chiral CFTs

This is a question about terminology. Given two vertex algebras $V_1$ and $V_2$ (= chiral CFTs), there are two kinds of maps $V_1\to V_2$ that one might want to consider. 1) Morphisms of VOAs that ...
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85 views

What is the 1/2 spin analog of the graviton called?

In some supergravities you have the gravition, gravitino, graviphoton and graviscalar. Each is analogous to each other in only sharing gravitational properties and nothing else. They differ by spin ...
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1k views

de Sitter and anti de Sitter metric

Is the following correct for the distance $d$ from the origin $(0,0)$ to point $(t,x)$ in the 2-dimensional de-Sitter and anti de-Sitter spaces? Here, $t$ is time and the distance may be called the ...
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What's the meaning of $\Delta E-W_{nc}=0 $?

Suppose a system of particles is subject to internal forces, some of which are conservative and some of which are non-conservative. Let $\Delta E$ be the change in mechanical energy of the system as ...
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What is the name and meaning of the integral of potential energy?

The paper, Significance of Electromagnetic Potentials in the Quantum Theory by Aharonov and Bohm makes reference to a term, $S$. I'm curious as to if this term has a name and to its meaning. $S$ is ...
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61 views

Why is Cauchy horizon named after Cauchy?

I think the title says it all; I have done a lot of Googling, but I could not find the answer. Since (I assume) the concept was discovered after Cauchy's death, I speculate that there is a connection ...
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50 views

Non-commutative field theory vs Non-commutative geometry

In the literature I have read about non-commutative field theory where the spacetime coordinates obey $$[x_i, x_j] = \theta_{ij}, \quad \theta_{ij} \neq 0.$$ However, I have also non-commutative ...
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Is the ‘diffracting angle’ talking about the first minimum or first maximum?

So when we talk about diffraction for single slits, we refer to the first minimum as the ‘diffracting angle’. However, in other experiments with wave particle duality (for example electron ...
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1answer
31 views

Fluids mixture density prediction

As you know 100 ml of H2O mixed with 100 ml ethanol is not 200 ml What is the official name of this 'volume loss'? Is it possible, and if so, how, to calculate, before mixing, what the density of a ...
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1answer
54 views

Ghost exorcisms of fields?

In Mack's paper "D-independent representation of Conformal Field Theories in D dimensions via transformation to auxiliary Dual Resonance Models. Scalar amplitudes", he makes the following statement ...
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Is there a word for the availability of a gas, normalized for pressure?

As a bit of background of what I'm getting at, consider that for the purposes of humans breathing and getting oxygen into their blood, 20% oxygen at 1 atm is equivalent to 100% oxygen at .2 atm. ...

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