# Tag Info

## New answers tagged terminology

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Sounds like graphene physics or something similar. You won't find it in a dictionary. In the band structures of many materials, it is common to find multiple similar points in reciprocal (momentum) space. For example, in silicon's band structure there are six distinct conduction bands that all have similar behaviour. These six points came to be known as ...

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My textbook uses $R$ for activity as corresponding to the decay rate.

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The English Wikipedia article for reluctance uses the term ‘magnetomotive force’. I like Tobias's answer better, so I'm accepting it, but I'm also recording this one. If somebody else adds another better answer, then maybe I'll switch!

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The set of all possible elements of the form $e^{i\alpha}D(x,p)$ with $\alpha, x,p \in \mathbb R$ verifying the commutation relations you wrote in addition to: $$D(x,p)^* = D(-x,-p)\:,\quad D(0,0)=I$$ is a group and it is called Heisenberg group, it is homeomorphic (diffeomorphic) to $U(1) \times \mathbb R^2$ but not isomorphic as a Lie group. It is a real ...

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We can realize the displacement operator as $$\tag{1}\hat{D}(x,p)~=~e^{x\hat{P}+p\hat{X}},$$ where the elements $\hat{X}$, $\hat{P}$ and ${\bf 1}$ generates the Heisenberg algebra $$\tag{2} [\hat{X},\hat{P}]=i{\bf 1}.$$ These elements can be realizes as differential operators in the Schrödinger representation. (See also the Stone-von Neumann theorem.) ...

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Line integrals of the magnetic field strength are magnetic voltage drops. Just google for "magnetic voltage drop" (including the double-quotes). In the quasi-static case ($\dot{\vec{D}}=\vec{0}$) the $\vec{H}$-field within a simply path-connected domain with zero current density has a magnetic potential. In this case you can calculate the magnetic voltage ...

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I assume you're thinking about Minkowski space, i.e. the metric $\eta_{\mu\nu}=\text{diag}(c^2,-1,-1,-1)$. You should be aware that the dot notation is purely a notational shorthand, and has no other information contained in it. In particular, by definition we have $$\dot{A}\equiv\partial_0A=\frac{1}{c}\frac{\partial A}{\partial t}$$ Thus, there is no ...

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Compressibility factor comes from the virial expansion, any (monoatomic) gas can be study as an ideal gas with Z=1 but it's obviously just an approximation. The problem is that for the ideal gas law you assume that the particles (atoms) are punctiform without a proper volume. In the real gas model we have to correct volume and pressure because of the finite ...

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As far as I'm aware, there is no term within physics that describes this distinction. To be clear, let me state what I think the distinction you're asking about is. Physics studies systems that exist in the real world. Computational science and mathematics do not, or at best can be thought of "inventing" their subject matter as they go along. Your question ...

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I've always treated anharmonic oscillators to mean the potential has the form $$V(x)=\gamma x^2 + \beta_ix^i$$ with $i$ being any value except 2, including negative values as well. Anharmonicity then follows as the deviation of the eigenvalue of $V(x)$ above from the harmonic solution. For example, the paper you link above, Case 1 has an energy eigenvalue ...

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One has to be careful with the given potential. To start with it must be shown that $$h=-(d/dx)^2+V(x),$$ defines a unique self-adjoint operator $H$, i.e., is essentially self-adjoint. In case $$V(x)=ax^2+bx^3+cx^4$$ with $c>0$ this is indeed the case. In fact the resolvent of $H$ is compact (these matters are discussed in the books by Reed and Simon), ...

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Before addressing the question directly, it should be helpful to sketch some relevant relations involving the notions timelike curve and light cone of an event (and here at first also distinguishing its "past" or "future" parts): Considering the light cone of one particular event, and an (open) timelike curve containing another identified event inside the ...

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Barring any other information, I'll tell you what I think equivalent temperature means in this case. In a laser gain medium (such as Rubidium) the atoms are put into a non-equilibrium excited state referred to as a population inversion. In an equilibrium treatment of thermodynamics it is impossible for a system to reach such a state because even at ...

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Confirmation bias might be what you're after. From wiki: Confirmation bias [...] is the tendency of people to favor information that confirms their beliefs or hypotheses. http://en.wikipedia.org/wiki/Confirmation_bias

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It's c for constant or celeritas, which means speed in Latin. Everyone uses it because it's convention. You could use $\xi$ or $\zeta$ or $\gamma$ or any other symbol you wanted, but then you'd have to explain what it meant, and people would have to go through the trouble to remember this every time they read your papers. Better to go with convention and ...

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The magnitude of acceleration is simply a measurement of change in speed per unit time. As an example, say you are in a car starting from rest and you begin to speed up. Say that you reach a speed of $20 {m \over s}$ in $2$ seconds. This means the magnitude of your acceleration is: $$a = {20 {m \over s} \over 2s} = 10 {m \over s^2}$$ That is, your speed ...

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Your question is kind of vague but I will try to respond. Acceleration is defined as the time rate of change of velocity. Since velocity has both magnitude and direction, so does acceleration. In other words, acceleration is a vector. The length of the vector is its magnitude. Its direction is the direction of the vector. So the magnitude of ...

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