1
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0answers
49 views

annealed randomness vs quenched randomness

what is meaning of annealed randomness and quenched randomness? in this article used this phrase to compare the model and earthquake data.
1
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0answers
24 views

Do diamagnetic ferrofluids exist?

I am wondering if there are ferrofluids or 'diafluids' that exist which are repelled by a magnetic field?
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0answers
53 views

Why are Newton's laws valid only for rigid bodies?

As far as I know, Newton originally wrote the first and second laws for a particle and under the condition that a collection of particles is rigid, we can write newton's second law for a body as $F_{...
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0answers
30 views

Stuck with physics tensile strength problem

So this was a question in my exam. I am not asking for the solution rather some help at a step. A glass spherical shell of radius $R$ has a point source of monochromatic light of wavelength $\...
1
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0answers
31 views

Space and absolute 0

If two objects like black holes or soild matter are separated by space, let's assume billions and billions of light years. While all other possible energy has left the area, and no new sources. Like ...
1
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0answers
73 views

Magnetic field outside the solenoid

I found solution to problem 257 from "300 Creative Physics problems" hard to understand. In that problem we have very long solenoid with coil wounded in one layer. Data such as: density of turns, ...
1
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0answers
45 views

The spatial Schwarzschild metric

The Schwarzschild spacetime is defined by the following line element \begin{equation*} ds^2 = - \left( 1 - \frac{2m}{r} \right)dt^2 + \frac{1}{1-\frac{2m}{r}}dr^2 + r^2 d\theta^2 + r^2\sin \theta^2 d\...
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0answers
45 views

Spacetime as a coset of a symmetry group

In the introduction to his nice PNAS paper on symmetry, David Gross said Einstein’s great advance in 1905 was to put symmetry first, to regard the symmetry principle as the primary feature of ...
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0answers
38 views

How to derive an expression for entropy generation in a diffusive, reacting continuum

I'm trying to understand a derivation from "The Thermodynamics of Linear Fluids and Fluid Mixtures," by Miloslav Pekař and Ivan Samohýl (2014). The derivation produces an expression for the entropy ...
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0answers
44 views

Reference for open XX spin chain with external magnetic field

I would like a reference on the diagonalization of an open XX spin 1/2 chain with homogenous external magnetic field. I am new to the subject and I haven't been able to find a reference for it. Edit: ...
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0answers
49 views

Proper time and asymptotic flatness

I'm trying to understand the concept of asymptotic flatness in general relativity, and came up with the following question: If the proper time $\tau$ is infinite for a timelike geodesic, does it mean ...
1
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0answers
58 views

How to create linear parallel magnetic field lines

I am trying to make ferrofluids create a flat surface between two points. Most of the magnet configurations I have seen have field lines that arc. So I'm asking if there are any circumstances where ...
1
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0answers
32 views

The force of a spring

I am new in continuum mechanics and I want to prove the formula which gives the force given by a spring : $$F_{max}= \frac{Ed^4(L-nd)}{16(1+\nu)(D-d)^3 n}$$ where : $E$ – Young's modulus $d$ – ...
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0answers
41 views

How to understand the instant state collapse in all references?

When a subsystem A of an EPR pair AB is measured, it's usually said that the state of B collapse instantly, and also this is true for all observers according to relativistic quantum information. ...
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0answers
42 views

How Quantum is EGY Duality Relation

I know that the Englert-Greenberger-Yasin (D^2+v^2=1 for a laser) duality relation is often considered an equation quantifying Wave-Particle Duality. However, when I was playing around with the ...
1
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0answers
60 views

What sorts of problems does asymptotically safe gravity face as a potential quantum gravity solution?

I've recently read an article by Ethan Siegel over at Forbes (he also blogs at Starts with a Bang) on asymptotically safe gravity as a possible alternative to string theory. I read the author's blog ...
1
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0answers
59 views

angular momentum of electromagnetic wave

EM waves that are circularly or elliptically polarized have angular momentum. Is there any experiment that proves/shows this ? like shine a light on something and it rotates ? The correspondence is ...
1
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0answers
69 views

How to measure the Fermi velocity in Dirac materials?

Suppose that one has a Dirac material (e.g., graphene), i.e., a system where there exists a number $N$ of identical Dirac cones (linear dispersion) at the Fermi energy $E_F=0$. How can one measure ...
1
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0answers
91 views

Unsolved Potentials in Path Integral

I just started learning on path integral on my own. It seems that the path integral method is not always able to be solved, depending on the potential. On the other hand, these potentials are ...
1
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0answers
78 views

Transition Amplitude in Field Theory

I am currently reading the "Quantum Field Theory" by Lewis Ryder. In chapter 5 he is talking about path integrals and says that the transition amplitude $ \langle q_f t_f \vert q_i t_i\rangle $ is $$ \...
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0answers
93 views

standing waves on a cylindrical jet

as we know, there are some perturbations on a falling jet which are always present and according to their wave number and the radius of the jet, they can grow and decay over time. so, imagine a jet ...
1
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0answers
45 views

Variation of Bazanski Lagrangian

The Bazanski Lagrangian is defined as $$ L=g_{\alpha \beta }U^{\alpha }\frac{D\psi ^{\beta }}{Ds} $$ and $$ U^{\alpha }=\frac{\mathrm{d} x^{\alpha }}{\mathrm{d} s} $$ $x^{\alpha }$ is the ...
1
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0answers
11 views

Simulate Band Bending and Band Alignment in Semiconductors

Are there softwares (simple ones preferred) where we can simulate the band alignments and band bending of a p-n junction, where we can vary properties of the junction materials such as carrier ...
1
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0answers
44 views

Gauss-Bonnet correction to Carnot's efficiency

Could any one tell explicitly, how did the author get $Tc$ Vs $\alpha$ Plot given in Figure 3 in Gauss-Bonnet Black Holes and Holographic Heat Engines Beyond Large N
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0answers
38 views

Experimental Bases for Schrodinger Equation and Matrix Mechanics

I am curious about the motivation for developing the Schrodinger equation (SE), and its subsequent acceptance. Are the primary experimental findings that led to the development of the SE: 1) the ...
1
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0answers
24 views

Initial quantum state of a molecule in an ensemble with Boltzmann distribution

The dynamic of rotational states of an ensemble of molecules in temperature T is the purpose of my simulations. Thermal distribution of molecules is defined by Boltzmann distribution and spacing ...
1
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0answers
108 views

Calculate the net force of water on the cylinder. (See picture)

I was working on this question, which wants me to find the net force on the cylinder due to the water. (It is 5 meters long) that is plugging a hole in a tank.I know to find the net downwards force I ...
1
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0answers
34 views

Are there any like masses that repel each other analogous to like charges in electromagnetism?

Just thought why the fundamental property of electromagnetism, electric charge, comes in two flavors i.e. positive and negative causing the electric force to be either attractive or repulsive while in ...
1
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0answers
37 views

Induced charges, electric potential

Consider a solid spherical conductor with charge Q on it, a charge q is placed at a distance r from the centre of sphere. Find the electric potential at the centre of sphere due to induced charges on ...
1
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0answers
37 views

To delimit and isolate a quantic system ? A pure fiction ? Or not?

An unreliable author wrote : "parameters that define uniquely the result of each trial and trial in an experiment. For instance, assume that we work with the polarization singlet. The power of ...
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0answers
35 views

Comparing relative velocities and kinetic energy

If object one is moving $0\frac{m}{s}$ relative to the Earth and object two is moving $1\frac{m}{s}$ and they both have $1kg$ of mass, then object one has no kinetic translational energy (relative to ...
1
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0answers
76 views

Kitaev honeycomb model: Ground state degeneracy

Consider the Kitaev honeycomb model: $\quad -J_x\sum_{x\; links} S_i S_{i+x}- J_y\sum_{y\; links} S_i S_{i+y}- J_z\sum_{z\; links} S_i S_{i+z}$. From Lieb's theorem, the ground state is given by, $...
1
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0answers
97 views

How does one calculate Feynman rules from a given lagrangian in QED?

I am a beginner in learning QFT. In homework problems in QED I often meet questions that asks one to calculate Feynman rules from some given lagrangian density. Some simple idea is to "read off" the ...
1
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0answers
134 views

Proof of correlation function formula in quantum field theory

I am trying to prove the following formula used in QFT: $$\langle\Omega|T\{\Phi(x_1)\dots\Phi(x_n)\}|\Omega\rangle = \frac{\langle 0|T\{\Phi_I(x_1)\dots\Phi_I(x_n)S\}| 0 \rangle}{\langle 0|S| 0 \...
1
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0answers
18 views

Removing conductive silver paste from a stainless steel plate

I've been doing some STM experiments on TMD material held down with silver paste. is there any recommend solvent for removing the paste? I was going to use IPA or ethanol in a sonic bath...any ...
1
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0answers
15 views

T invariance in flavored meson system

Consider Kaon CP conjugate states $\left|K^{0}\right>$ and $\left|\bar{K^{0}}\right>$. The physical states i.e, eigenstates of effective hamitonian can be written as \begin{equation} \left|M_{a}...
1
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0answers
63 views

In an equilibrium of two systems, why is not true that $\frac{\delta S_{1}}{\delta N_{1}} = \frac{\delta S_{2}}{\delta N_{2}}$?

Why is not true that $\frac{\delta S_{1}}{\delta N_{1}} = \frac{\delta S_{2}}{\delta N_{2}}$ across two systems that exchange particles? It is true, instead, that $\frac{\delta F_{1}}{\delta N_{1}} = ...
1
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0answers
32 views

Cosmological inflation in LQG/LQC

I seek the state-of-the-art report on how cosmological inflation is described by loop quantum cosmology. I know that LQG/LQC predicts a big bounce to replace the classical big bang singularity of GR. ...
1
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0answers
55 views

Is time-1 map of a Hamiltonian vector field on a cylinder always twist?

I have a one degree of freedom analytic Hamiltonian $H(q,p)$ defined on a semi-infinite cylinder, i.e. $(q,p) \in \mathbb{T} \times \mathbb{R}^{+}$, such that all level sets $H(q,p)=c$ are closed ...
1
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0answers
11 views

Reactor opening and total time to reach a specific temperature

Let's say I have a reactor (we assume that its shape can be approximated by a horizontal cylinder) in which there is air at the temperature of 1000K and at pressure of 1.5 bar. Now, I want to open it ...
1
vote
0answers
69 views

Theta-parameter vacuum energy

Suppose we have $\theta$-field in QCD (in a special case of constant $\theta$ it reduces to ordinary $\theta$ parameter): $$ \tag 1 Z_{\theta} = \int D[\psi_{QCD}]e^{iS}, $$ where $$ \tag 2 S = \int d^...
1
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0answers
50 views

Why is the enclosed area of a voltage-charge Lissajous figure to the dissipated energy per cycle?

These Lissajous figures turn up in the study of Dielectric Barrier Discharges driven by AC voltages, but I believe the concept of the "dissipated energy=area enclosed curve" is much more general. By ...
1
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0answers
68 views

How do I decide when to use raised/lowered indices when calculating the amplitude of a Feynman diagram?

I am learning the Feynman rules for QCD. The book I am reading tells me that gluon propagators contribute a factor of $$\frac{-ig_{\mu\nu}\delta^{\alpha\beta}}{q^2}$$ However, in one of the ...
1
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0answers
33 views

The “general uncertainty” of the harmonic oscillator defies the correspondence principle?

If you use the definition of $(\Delta x)^2 = \langle n | x^2 | n \rangle - \langle n | x | n \rangle^2$ and the same for $(\Delta p)^2$ to calculate $\Delta x \Delta p$ for the state $|n\rangle$ of a ...
1
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0answers
41 views

What are the first couple terms of the Taylor series for the evolution of this network of capacitors and resistors?

note: This is a computational problem, and I only need approximate accuracy, so the overall goal is, for a given accuracy and $\Delta t$ to compute the state of the system at $t+\Delta t$ to within ...
1
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0answers
50 views

History of Renormalization Group

I want to study from an historical point of view the renormalization group (starting from statistical mechanics). Are there any historical (but also technical) books about this? Thanks.
1
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0answers
33 views

Asymptotic expansion with stationary phase

I am reading Rudolf Haag's book on "Local Quantum Physics", and on page 89 he writes that the following function $f(t,\vec{x}) = \int \tilde{f}(\vec{p})\exp(i(\vec{p}\cdot\vec{x}-\epsilon_{\vec{p}}t))...
1
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0answers
48 views

Substantial uneasiness as to the Joule free expansion (unresolved in spite of many readings)

Ok so, to do things well, let me present the set-up: we have an insulated container that is partitioned into two equal halves, one of which contains an ideal gas with parameters P1, V1 and T1, the ...
1
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0answers
31 views

Does curvature of space affects magnetic field?

I just want to know can strong gravity such as a black hole bends magnetic field lines?
1
vote
0answers
24 views

Photo's vector characteristic

In Frank Close's infinity puzzle, it says that to maintain the invariance for electric charge requires some means to transmit information about the local charge of gauge to electric charges elsewhere. ...

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