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0answers
110 views

Why is the following gauge transformation singular?

Suppose I have a single particle Hamiltonian: $H=\frac{p^2}{2m}+\frac{\hbar k_0}{m}\vec{\sigma}\cdot\vec{p}$, either for boson or fermion. I do a gauge transformation ...
1
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0answers
248 views

Small angle approximation for coupled pendulum

I am looking at a coupled plane pendulum problem where the pendula are identical with mass $m$ and length $r$, and connected by a spring with spring constant $k$ and an equilibrium seperation $d_0$. ...
1
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0answers
154 views

Holographic principle and holograms

Holographic principle or Maldacena's duality is a theory that says that the volume of space can be described by just looking the information encoded on a boundary to the region of that space. ...
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0answers
50 views

Information and Black holes

From Youtube: A Thin Sheet of Reality: The Universe as a Hologram (Full) I have a few questions: Why there are not layers of information on a black hole? If the information is stored in the ...
1
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0answers
105 views

$E$ and $B$ fields in Axial Gauge

I am trying to compute the $\vec{E}$ and $\vec{B}$ fields in the Axial gauge ($n \cdot \vec{A}=0$) where $n^2=1$, but I'm having trouble seeing the usefulness/how it simplifies the equations.
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0answers
75 views

Boundary Condition for Generating Evanescent Waves

I'm reading through Novotny and Hecht's book on Nano-Optics (Principles of Nano-Optics), and I've come across a subtlety in the boundary conditions for evanescent wave generation (via total internal ...
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0answers
82 views

Action of conformal generators on fields

I am calculating the action of the conformal generators on fields, to be more precise on wavefunctions. For now, I'm classical. I will just paste the part of my report on this to show what I am ...
1
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0answers
31 views

Quantum Mechanisms for Isotope Fractionation

Are there any quantum properties that would enable isotope fractionation? For example, atoms with odd versus even numbers of neutrons are fermions and bosons, respectively. Has any work been done ...
1
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0answers
79 views

Weak gravitational lensing multispectral, multibackground correlations

My understanding of weak gravitational lensing is that it assumes random alignment distribution of galaxies in order to estimate statistical shear and convergences, which are used to estimate matter ...
1
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0answers
73 views

Why do “virtual states” in Raman spectroscopy have absorbance profiles distinct from either the ground or excited states of an absorbing material?

Do virtual states in Raman spectroscopy have distinct and observable dipoles that can interact with and/or induce dipoles in other molecules (over extremely short femtosecond timescales)? This notion ...
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0answers
80 views

Matrix integral in multi-matrix model

Though it is a mathematical problem, maybe more physicists know it well. In quiver matrix model which is reviewed DV or CKR, the path integral reduce to the matrix integral $$Z \sim \int ...
1
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0answers
313 views

Does coffee with cream cool slower than black coffee?

At Modernist Cuisine, Nathan Myhrvold states that "Coffee with cream cools about 20% slower than black coffee". He then gives three reasons, two of them related to radiation and the third one to the ...
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0answers
149 views

Canonical transformation problem

(Apologies if HW questions are not allowed -- I couldn't really find a definite answer on this) Question Let $Q^1 = (q^1)^2, Q^2 = q^1+q^2, P_{\alpha} = P_{\alpha}\left(q,p \right), \alpha = 1,2$ ...
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0answers
65 views

Is there a consensus on the definition of wavelength for a solitary wave?

Solitary waves are by definition a wave of single nature so the usual definition for periodic waves does not apply. R. Dalrymple provides a definition but I saw a lot of other websites and papers ...
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0answers
61 views

What is the definition of a charge-neutral operator?

What is the definition of a charge-neutral operator? I guess it means something like: it is invariant under charge conjugation. It that correct?
1
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0answers
205 views

TKNN invariant changes due to continuous deformation of parameter space

Naively, I would assume that a topological invariant remains invariant under continuous deformations of whatever space the invariant belongs to. In the case of topological insulators, this space is ...
1
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0answers
239 views

Step in derivation of solution to Dirac equation for hydrogen

My text, when solving hydrogen in the Dirac equation, makes the claim $\varphi_{j m_j}^{(+)} = \frac{\mathbf{\sigma} \cdot \mathbf{x}}{r} \varphi_{j m_j}^{(-)}$ where $\varphi_{j m_j}^{(\pm)}$ are ...
1
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0answers
80 views

What is a potential in De-Broglie-Bohm theory?

As I have so far understood, the De-Broglie-Bohm theory is based on two equations: The Schrödinger equation. The Guiding equation of the De-Broglie-Bohm theory. In the Schrödinger equation (as ...
1
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0answers
350 views

Questions about Michelson interferometer

I have been doing experiment on Michelson experiment, but I don't quite understand why white light results in an interferogram with very few fringes, and why are they necessarily Gaussian? I know that ...
1
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0answers
239 views

How does the expectation value of the square of angular momentum transform under translations?

In quantum mechanics the angular momentum operator is defined as $$ \mathbf{\hat L}=\mathbf{\hat x} \times \mathbf{ \hat p} $$ This definition explicitly depends on the choice of the origin of the ...
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0answers
33 views

Is there a difference in binding energy between a regular material and a doped one?

Say Silicon and boron doped silicon. Would the doping affect the binding energy? Could I see this in an XPS spectra?
1
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0answers
309 views

Two particles in infinite square potential

Consider two non-interacting distinguished particles in one-dimensional infinity square potential. Suppose the particles have the same mass $m$, and the potential is zero in the region ...
1
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0answers
454 views

Stresses on an inclined plane

Background This issue has been bothering me for a few days now. It's actually part of my homework, but I've already finished them and in a sense they're not part of the question here. What I would ...
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0answers
193 views

Derivation of Scattering Equation 9.88 in Thornton & Marion

I am confused as to how a particular equation in Thornton & Marion's 'Classical Dynamics of Particles and Systems' was derived. It is equation 9.88, on page 354 of the fifth edition. An incoming ...
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0answers
59 views

Is there any “fundamental” uncertainty to the timing of the Big Bang?

I wondered whether, under the probabilistic interpretations of QM, the timing of the Big Bang (or perhaps any other historical event) is fundamentally as uncertain as (or: like) other (e.g., future) ...
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0answers
205 views

More physical explanation of impurity energy levels in a doped semiconductor?

I'm reading about doped semiconductors in Ashcroft and Mermin. They tell you that when donor impurities are added to a semiconductor, their energy level $E_d$ is just slightly below the conduction ...
1
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0answers
134 views

Buoyancy Correction for a Kater Pendulum

Question: Consider a Kater pendulum: that is, a rod with two cylindrical masses at both ends, with a knife edge between the two masses and another between one ...
1
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0answers
103 views

Finding kinetic friction coefficient

A box is thrown up an incline with degree $\alpha$. the kinetic-friction coefficient is $\mu_k$. the body returns back to its start point. a. prove ...
1
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0answers
255 views

One-loop beta functions of the Standard Model

For my master's research on energy scale independent combinations of renormalization group equations in supersymmetric theories, I need an overview of all the one-loop beta functions of the Standard ...
1
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0answers
194 views

Formula for residence time/turnover rate with unsteady state

I'm not sure this is the correct place to ask my question... but maybe someone could still help me. I'm looking for a way to calculate the residence time/turnover rate. I have the production and ...
1
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0answers
33 views

If the absolute horizon were exclusionary of matter, what supernova behaviors would that predict?

Kip S Thorne's "Black Holes & Time Warps", 1994 paperback, p.415, Box 12.1: ... The absolute horizon is just a point when created, but it then expands smoothly, like a balloon being blown up, ...
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0answers
118 views

The difference between Z boson couplings for quarks and antiquarks

I am trying to work out the difference between Z boson couplings for quarks and antiquarks. I know that for quarks the Z has the following couplings: $Z_u^- = \frac{1}{\cos \theta_w}(0.5 - ...
1
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0answers
37 views

Why do 3D holograms need curved lines?

I'm making a scratched hologram and I'm interested in we have to make curved lines to get a 3D image.
1
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0answers
54 views

Solving for the phase shift of a neutron due to precession in magnetic field

In the famous experiment that was used to prove the sign change of the wave function due to a rotation of 2$\pi$ by Werner et al. It is stated directly that the phase shift of the neutron beam is ...
1
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0answers
78 views

3D Surface Related Multiple Elmination (SRME)

Let's assume we are looking at first order multiples of the same surface (i.e no peg leg, etc). I am looking at marine 3D SRME and I am a little confused as to how this works. I understand that in the ...
1
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0answers
151 views

Gauge fixing the Einstein's gravity action

This is in reference to this paper, arXiv:1204.4061. I was wondering if someone can give me a reference which explains this gravitational gauge fixing that they have done in $2.10$ and how that ...
1
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0answers
97 views

Running chargino/neutralino masses in MSSM

Consider the plot below, showing the running of different masses due to renormalization for a certain point of the (c)MSSM. I am able to exactly reproduce the plot, including the running of M1, M2, ...
1
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0answers
44 views

Some question on the definition of flux in the projective construction?

Here I have some confusing points about the definition of flux in the projective construction. For example, consider the same mean-field Hamiltonian in my previous question, and assume the $2\times 2$ ...
1
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0answers
300 views

Introductory exercise set with solutions for string theory

I am trying to self-study string theory, beginning with Ibanez and Uranga (String Theory and Particle Physics). Unfortunately, the book contains no problems, so I'm not sure whether I am fully ...
1
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0answers
80 views

How to analyze this constraint question

Let $\gamma$ be a smooth curve in the plane, and introduce curvilinear coordinates $q_1,q_2$ on a neighborhood of $\gamma$; $q_1$ is the direction of $\gamma$ and $q_2$ is distance from the curve. ...
1
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0answers
77 views

Thermal exfoliation of graphite oxide

I have been reading up on the production methods of graphene, and one that I found interesting in particular was the thermal exfoliation of graphite oxide. From what I gather the basic idea is that ...
1
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0answers
80 views

Casimir force between plate and sphere

In our quantum optics lecture we derived the formula for the Casimir force between two plates (or at least the force per unit surface, since for two infinite plates we would have an infinite force). ...
1
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0answers
64 views

How does linearity of a measurement imply that the commutator of all measured observables are $c$-numbers?

I really don't understand with the linearity conditions I have where this comes from.
1
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0answers
142 views

Linearized gravity and symmetries

I have naive question. When we analyzing weak gravity field we introduce expression for metric tensor as $$ g_{\mu \nu} = \eta_{\mu \nu} + h_{\mu \nu}, \quad \eta_{\mu \nu} = diag(1, -1, -1, -1), ...
1
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0answers
57 views

Recover activity from photo at Fukushima

This photo was published at stern magazine online. I wonder which information about the physical quantities could be reconstructed or computed given this photograph, the exposure time, and the ...
1
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0answers
427 views

Degeneracy in molecular rotation energy levels for asymmetric molecules

I was recently reading Atkins' Physical Chemistry, the topic of rotational energies of molecules. It states the degeneracies of spherical top, symmetric and linear molecules as being $(2J+1)^2$, ...
1
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0answers
77 views

River model of spacetime for arbitrary situations

This paper describes black holes as space flowing inward (the rotating hole also twists in a weird way): http://arxiv.org/abs/gr-qc/0411060 The proper time given by the objects is the same as ...
1
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0answers
66 views

Expanding Universe Balloon Analogy - Anything Similar for Time?

It is difficult to imagine the infiniteness of space and how it itself is expanding rather than the universe expanding into something else. A helpful analogy is that of drawing little dots ...
1
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0answers
66 views

Transitions in a magnetic refrigeration

The graph below (see attached) shows the measured magnetization against temperature at room pressure for the material Gd and for another material for use in a magnetic refrigerator at room ...
1
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0answers
120 views

Space contraction: what do we see

This is my opinion about what we will see. When the pipe arrive at the bar, we will be unable to see some part of it anymore (the pipe will absorb the light emitted by the bar), even if the pipe and ...

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