0
votes
0answers
39 views

thrust-bursting towards a destination in space

<--burst of thrust------|ME in a ship>----->>--<<--laser radar--<<---->>---||destination In the above, I imagine myself in a ship, marking my speed to a far off destination with laser ...
0
votes
0answers
31 views

I would like to ask any interested reader about “Quantum Bidding in Bridge”

see http://journals.aps.org/prx/pdf/10.1103/PhysRevX.4.021047 I would like to see how specific examples are worked out. Specifically, details on how the quantum protocol in figure 1. of the above ...
0
votes
0answers
67 views

Calculation of energy eigenvalues of $\hat{x}^4$

I would appreciate help in calculating the energy eigenvalues associated with $\hat{x}^4$, with $\hat{x}$ expressed using the ladder operators for harmonic oscillators. $\hat{x} = ...
0
votes
0answers
20 views

Transmission Line above infinite plane connected by impedance line - Is my drawing correct?

Okay, I was doing a question on transmission lines. The setup is a wire placed at distance $d$ above an infinite conducting plane. The impedance of such a line is $Z_0$. Then there is an impedance ...
0
votes
0answers
18 views

Condensate fraction and momentum distribution in cold atom experiments

In ultrcold atom experiments, people usually use time-of-flight technique to measure the momentum distribution, then get the condensate fraction information from the interference pattern. What is the ...
0
votes
0answers
282 views

Electric Potential due to conducting sphere and conducting shell

The problem statement, all variables and given/known data A solid conducting sphere having a charge Q is surrounded by an uncharged concentric conducting hollow spherical shell. Let the potential ...
0
votes
0answers
34 views

diffraction from sphere solution

I want to solve a problem of plane wave diffraction by a large sphere. There is a formula that I found from papers, but I think needs numerical solution. please help me to solve it The formula is ...
0
votes
0answers
18 views

The 4 R's of radiotherapy - redistribution

I'm having some trouble of getting a grasp of this term, so I hoped someone could enlighten me. As far as I understand, the idea behind it is, that cells have different cycles in their "life", and in ...
0
votes
0answers
88 views

Determining diameter of effective image circle of large lens in a Camera Obscura

I am in the process of gathering materials and designing a large lensed Camera Obscura. I would like to estimate the approximate diameter of the image circle and the approximate field of view. in ...
0
votes
0answers
23 views

A question on lowering the total spin

Is there a way to lower the total spin of the state and fixing the $S_z$ rather than lowering the $S_z$ by spin ladder operator? Or in other words, how to connect the $S=1$ state with $S=2$ or $S=0$ ...
0
votes
0answers
50 views

Temperature coefficient of resistivity (resistance) in function of temperature

If I'm correct, the definition of the temperature coefficient of resistivity at a certain reference temperature is the derivative of the resistivity in function of the temperature, divided by the ...
0
votes
0answers
33 views

Why are quark up and down an isospin doublet?

I have some difficulties in understanding the isospin of quarks. As far as I am concerned, the isospin formalism is used to express the physical property of electric charge. I mean: what I know ...
0
votes
0answers
21 views

Why is relative biological effectiveness of photon and electron the same ?

I was wondering, why seemingly two distinct particles have the same RBE (relative biological effectiveness) ? Would the charge of electron not do more/less damage ? While on the subject, does anyone ...
0
votes
0answers
33 views

Making elementary guess regarding current in AC circuits

I was just studying the comparisons, between A.C, and D.C, and the effects they can produce in electrical circuits (viz, Joule-heating, Peltier-effect and Seebeck-effect in thermocouples, ...
0
votes
0answers
9 views

Transient Stress and Piezoelectric Generators

From what I can gather, the piezoelectric effect links mechanical stress to the potential difference across a material, with a two-way relationship between the two (motor or generator). I don't know ...
0
votes
0answers
37 views

Geometric Interpretation of these equations of motion?

I was reading my Engineering Mechanics book, and it derived some strange looking integrals I'll have to apply. I could memorize them, but I'd rather understand them - then I won't have to memorize. ...
0
votes
0answers
44 views

Beat like Interaction with electromagnetic waves

So I was reading earlier on this website and I came across some question similar to this but I want to lead it Into a different direction. I understand that two interacting superposition waves (that ...
0
votes
0answers
89 views

Has this approach to Coulomb force/Newton gravity unification ever been published?

Introduction: When toying with gravitational and electromagnetic equations in my undergrad days I stumbled upon this interesting relationship. With the very childish hopes of unifying gravitation ...
0
votes
0answers
27 views

Any way to Find the Position Function of a body under gravitational force?

Here's the problem I am trying to find a solution to: Consider a heavy point particle of mass $m_2$ fixed at a point (preferably the origin) and another light point particle of mass $m_1$ at an ...
0
votes
0answers
41 views

Jacobian of a transformation on Maxwell equations in cylindrical coordinates

In an area called transformation optics, they transform Maxwell equations from one space coordinate system to another, and then using the fact that Maxwell equations retain the same format under ...
0
votes
0answers
17 views

Ask procedure to obtain reduced density matrix

I have a mutipartite system; the subsysyems having interacted. Now, to find reduced density matrix for any single subsystem, is the order of partial traces(over remaining subsystems) important?
0
votes
0answers
19 views

Flaring stress in thread relief

I have a problem to understand what does exactly mean (definition, how is induced, in which direction works) "flaring stress" in reference to the thread relief of internally/externally threaded ...
0
votes
0answers
36 views

Thermal Conduction through sphere

In general, a sphere with conductivity $\kappa$, heat capacity per unit volume $C$ and radius $R$ obeys the differential equation at time t: $$C\frac{\partial T}{\partial t} = \kappa \frac{\partial^2 ...
0
votes
0answers
25 views

MS scheme and its RG equation by Cheng and Li

I've got a question about derivation of RG equations made in "Gauge theory of elementary particles" by Cheng & Li. At page 79 (page 97 in Russian edition) they represent bare parameters ($\mu_0, ...
0
votes
0answers
37 views

Brownian motion and physical meaning

I have read Stochastic Differential Equations by Bernt Oksendal It constructs Brownian motion by Kolmogorov extension theorem by consider $p(t,x,y)=(2\pi t)^{-n/2} e^{- \frac{|x-y|^{2}}{2t}}$ But I ...
0
votes
0answers
36 views

Mutual Inductance of co-planar (but not concentric) loops

Two small wire loops, each with radius b, are placed a distance $d >> b$ apart. The loops are oriented as shown below; i.e., both loops lie in the x-y plane. Each loop carries the same current ...
0
votes
0answers
36 views

Infinite Round Square-Well zeroes of Spherical Bessel function

Consider a potential well where the potential is zero within a spherical well of radius a centered on the origin. Taking $a$ as our length scale and $\hslash^2/(2ma^2)$ as our energy scale, we gain ...
0
votes
0answers
42 views

How to calculate net power output of heated, expanding air?

I'm interested in designing and building a Stirling engine which uses air that has been heated, which expands and then acts upon a piston producing power. There is a fixed amount of air inside the ...
0
votes
0answers
27 views

Particle in a box under harmonic driving

Is the particle in a box under harmonic driving electric field solvable analytically? Here is the Schrodinger equation: $$ i\frac{\partial \psi(x,t)}{\partial t}=\left[-\frac{1}{2} ...
0
votes
0answers
18 views

Origin of Overpotential in Electrochemical Cell

I'm well aware of the significance of overpotential and how it is defined to be the difference between the thermodynamically determined equilibrium potential and the experimental potential required to ...
0
votes
0answers
71 views

How does cryptochrome produce quantum entanglement?

I found this video on the net, which explains how a bird called "European robin" uses a trick based on quantum entanglement to see the earth's magnetic field. I am just asking if some of you know any ...
0
votes
0answers
21 views

Pseudo force in rotational motion?

If a cylinder is in combined rotation and translation on a moving surface(say a plank with some acceleration), while solving for the acceleration of the centre of mass of the cylinder, do we consider ...
0
votes
0answers
50 views

Potential Around Suspended Particles

In my textbook, the classic example of a dielectric sphere suspended in a dielectric solution is solved, and a general form for the potential inside and outside of the potential is given without ...
0
votes
0answers
23 views

The speed of electrons moving in different medium

Can one have a simple (dimensional-analysis) model to evaluate the speed of electrons moving in: (1) a copper wire (2) a silver wire (3) a gold wire (4) a semiconductor wire let's use meter over ...
0
votes
0answers
54 views

How does QED explain magnetism?

I understand how QED explains, for example, Coulomb's law. But how does it explain the behavior of two bar magnets whose N and S poles attract one another?
0
votes
0answers
38 views

Poynting Vector between Capacitor - With electrons in between!

Consider a capacitor with voltage $V = V_0 cos(\omega t)$, radius $a$ and separation $d$. Electrons are distributed uniformly with number density $n$. I want to find the poynting vector between the ...
0
votes
0answers
50 views

Conditions that the coordinate must satisfy in order to become local inertial

Consider the coordinate transformation $$ \tilde x^a=x^a+\frac{1}{2}\Gamma^a_{bc}x^bx^c $$ I have shown that at the origin $O=(0,0,0,0)$, $$ \frac{\partial\tilde g_{ab}}{\partial\tilde x^c}=0 $$ ...
0
votes
0answers
33 views

(Special Relativity) Points that can be seen by an observer

Let the metric be $$ ds^2=(1+gz)^2dt^2-dx^2-dy^2-dz^2 $$ where $g$ is a positive constant. Let an observer be stationary at $x=y=0$ on the surface $z=0$ and look upwards at an angle $\theta$, how ...
0
votes
0answers
83 views

group velocity in non dispersive medium

In a non-dispersion medium, phase velocity is equal to group velocity of waves. Consider a free quantum particle moving in one dimension say $\text{x}$ axis. There would be matter waves associated ...
0
votes
0answers
19 views

Zero field cooled / field cooled susceptibilities

I'm studying magnetic properties of nanoparticles in a liquid carrier and trying to understand better zero-field-cooled/field-cooled curves. We use the Stoner–Wohlfarth model and Chantrell ...
0
votes
0answers
26 views

Modify permittivity with a current?

Permittivity is a function of frequency from an existing EM wave. But permittivity in some ways describes how a wavelength of light interacts with a metal. Certain wavelengths, sense different ...
0
votes
0answers
46 views

Quick question on Perturbation theory - How do I evaluate this probability?

We know that hamiltonian for interaction between an electron and external field along $z$ is: $$\hat H = \frac{e\hbar B}{2m}\hat \sigma_z = \frac{\hbar \omega}{2} \hat \sigma_z $$ This has energy ...
0
votes
0answers
32 views

Charge Image Problem: Work done on charges on the plate

Assume there is an infinite grounded conducting plane in the $xy$-plane. Assume also that a point charge is being brought slowly from $z=\infty$ to $z=z_0$, slowly enough that the problem is treated ...
0
votes
0answers
34 views

Using Optic Lens to Simulate Distance

I have an actual scenario, where I have to align a particular electronic optical device to two objects in the distance (2-3 km away), forming a right angle at the point where the optical device is. ...
0
votes
0answers
23 views

Why is the Poisson - Boltzmann equation not suitable for high potential?

The Poisson - Boltzmann equation is to find the potential whose charge density obey the Boltzmann distribution. If the potential is not large compare to $k_BT$, the PBE can lead to the Debye–Hückel ...
0
votes
0answers
14 views

Dipole and multipole bound state anions: Do these bound electrons behave exactly like conventional electrons in the molecular orbitals?

Recently, I read about dipole and multipole bound anions. Dipole bound anions are those, if I understood correctly, when an electron is attached electrostatically on a neutral molecule which is polar. ...
0
votes
0answers
101 views

Free-Free Modal Analysis of Vibration

I am guessing if it possible to use Modal Analysis to simulate the vibration on a Free-free object. By free-free, I mean an object which don't have any fixed points and vibrates freely. Directly ...
0
votes
0answers
29 views

Charges in a molecule and rotation invariance

Why are the charges of atoms in a molecule not invariant under the rotations of the molecule? My intuition is that the charges should not change under the rotation of the molecule, because their ...
0
votes
0answers
46 views

Quantum entanglement, principle of locality and speed of light

I know it's a newbie question but I was wondering about how the principle of locality and the speed of light's limit fit with the phenomena of quantum entanglement? I've read that, due to Bell's ...
0
votes
0answers
24 views

Replacing diode in circuit analysis?

While analyzing circuits containing diodes in reverse bias I replace it with a pure insulator for simplifying things. Similarly can I replace a forward biased diode with a conductor and a varying ...

15 30 50 per page