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Suppose there was a small block on top of a larger block on an incline and there is both kinetic friction between the block and the incline and static friction between the blocks. If both blocks accelerated together down the incline, could you just discount the static friction as they cancel out for the system of the t... |
I'm slightly confused about Faraday's law. Is it directly proportional or is it equal to the rate of change flux? If it is proportional, what's the proportionality constant? It might seem like a stupid question and I hope I am not wasting your time.
|
Something I'm sort of struggling to figure out. Let's say I have a given length of wire to make solenoids. I wrap it tightly in all cases and get some turns per distance $n$ that will remain constant, as will the current through my coils, $i$, and the area of my coils, $A$. In one case I wrap all my turns serially, ... |
For 3D conducting objects we know that any excess charge placed inside will go to the boundary, the reason given is that the free charges will move around till they cancel the field inside the conductor and if $E=0$ it means $\rho=0$ hence the excess charge has nowhere except the boundary to go to.
But it we've a charg... |
I'm looking to understand how Bonner Sphere System works. I understand the whole idea, but I'm lost about how a single sphere can produce a whole spectrum.
For instance with He3 thermal detector, the reaction is the following :
He3 + n -> H1 + H3 + 764 keV
H1 and H3 kinetic energies are both determined by conservation ... |
I've been following Behzad Razavi's Microelectronics book. Here is the particular excerpt from the book which is confusing
An interesting question that arises here is: are the minority carrier concentrations
constant along the x-axis? Depicted in Fig. 2.29(a), such a scenario would suggest that
electrons continue to f... |
I am trying to calculate the integral
\begin{align}
E_n(\mathbf{r}) = \int \frac{d^n \mathbf{k}}{(2\pi)^n} \frac{ e^{i\mathbf{k}\cdot\mathbf{r}} }{ \mathbf{k}^2 + m^2 }
\end{align}
for $n > 2$ (the case $n=3$ is well-known and calculated here).
Related is this post where it is stated that for $n \neq 2$ this should be ... |
The relativistic velocity addition $\oplus$ for 3-velocities $\bf{u}$ can be constructed from Lorentz boosts $\Lambda$ acting on 4-velocities $u$
$$ u \to u^\prime = \Lambda(v) \, u \implies \bf{u}^\prime = \bf{v} \oplus \bf{u}. $$
The boost do not form a sub-group or the Lorentz group, neither does $\oplus$ defines a ... |
Assuming there is friction contrary to the question above,
I derived the equation as in my textbook:
$$a_x=g(\sin\alpha-\mu_{k}\cos\alpha)$$
Testing special cases, if $\alpha=90°$,$a_x=g$, just as we would expect in a free fall. However, letting $\alpha=0°$, we get
$$a_x=-\mu_{k}g$$
Shouldn't $a_x=0$ as on a horizonta... |
I have a doubt regarding, why changing of position in brillouin zone changes the energy levels?
This is because there is a change in the wave functions at every point in brillouin zone. But why is wave function changes? Here, I have attached band structure of 'Si'.
How can we identify the s, p, d, f orbitals by lookin... |
In Wald section 9.2 page 221 he says that
We turn our attention; now , to null geodesic congruences. Again, we
parameterize the geodesics by an affine parameter $\lambda$, but ,
unlike the timelike case, we now have no natural way of normalizing
the tangent field $K^\alpha$ and thereby adjusting the scale of
$\lambda$... |
Nobel laureate Richard Feynman once said that if two persons stood at arm’s length from each other and each
person had p = 1% more electrons than protons, the force of repulsion between them would be enough to lift a “weight”
equal to that of the entire Earth. He stated to carry out an order of magnitude calculation to... |
Lets say I have a ammeter(Digital or analog) that I want to calibrate . I can use another good ammeter to calibrate it .But in the early days, for the 1st ammeter that was ever created , there was no other ammeter that could have been used to calibrate it.So my question is , how was the 1st ammeter even calibrated ?
|
Action is represented by $S[Q(t)]$ where $Q(t)$ is the name of a single complete path in the configuration space of a system. The path starts at the point $q_i$ and ends at the point $q_f$. Suppose that the system is at $q_i$ at the time $t=0$ and then suppose it reaches $q_f$ at $t=T$. Then the action functional for t... |
I had been working on a problem recently and i stumbled upon something I did not quite get. So the relevant part of the problem is like this:
Suppose we have two conducting spheres with radii a and
b separated by a distance, r, much greater than either
radius( refer to diagram below). A total charge Q is shared between... |
Assume that density of the body is less than the fluid.
If we put a body in a given fluid the buoyant force equalise the weight of the body. If we increase weight, the buoyant force increase?
If it does So it must be self-adjusting force, is it have any maximum value just like friction as?
|
Does it mean that If we provide 100 KeV energy to the nucleus in that resonant state then it will decay through a neutron emission?
|
I wonder if double-slit experiment can be considered a proof of non-existence of local hidden variables in quantum mechanics?
Consider this: probability $P(A \: \textrm{or} \: B)$ that either one of two events A and B or both happen is
$$
P(A \: \textrm{or} \: B) = P(A) + P(B) - P(A \: \textrm{and} \: B)
$$
Additional... |
I'm a bit confused about the difference of the charge conjugated state (applying C-operator) and the antiparticle of a certain particle.
As an example:
To get the antiparticle of the $\Sigma^-$ $(dds)$ baryon, as far as I know, we have to apply a CPT-transformation. Well I learned to simply "convert all quarks to their... |
I was preparing hummingbird food. To get the feeders filled and hung quickly, I placed the pot in a sink with a similar or greater volume of cool water in it. I hypothesize that absent any other factors, stirring the water in the pot will decrease the total time until the syrup, sink water and pot reach an equilibrium ... |
Similar to how the perpendicular axis theorem is analogous to the Pythagoras' theorem I wanted to find an expression analogous to the cosine law to find the moment of inertia. In other words given two axis $L_1$ and $L_2$ (Slope of the angle between them $= m$) and the moment of inertia of a body with respect to these ... |
I have been asking and learning about angular momentum. I know that an object traveling straight has ang. momentum about a point of rotation.
Just curious, this example shows the torque acting on a meteor traveling in a straight line. Therefore, wouldn't there be work done by torque? Normally work would be $W=\int \... |
Since I couldn't write the complete question in title: Effect of this change on saturation photocurrent?
I had reasoned that since saturation photocurrent depends on intensity of incident light which is given to be constant (energy per unit area and per unit time is constant).But the answer says that Saturation photocu... |
If we have a very strong electromagnetic field, it stops being linear, Maxwell's equations stop working ($10^6$ Tesla or $10^9$ Newton/Coulomb);
Why can't we say the same thing for gravity? Since the field equations of gravity aren't linear couldn't we make the assumption at a lower limit , they become linear?
If the ... |
Because when we look at the way Dirac got his equation he factored out the energy momentum relation in special relativity effectively and at a certain point he noted that there was that the factoring can only be done if the coefficients he introduced were anticommutator. And he finally noted the similarities with Pauli... |
The definition of parallel transport is $t^iD_i u^j=0$, where $\vec{t}$ is the tangent vector to the curve and $\vec{u}$ is the vector being parallel transported along the curve. In flat space, using above definition, we have $t^i \partial_i u^j=0$, and usually parallel transport means $\partial_i u^j=0$, which suggest... |
In diffraction experiments, the pattern on a screen is the fourier transform of the aperture when it is a Fraunhofer diffraction (when the screen is far from the aperture).
When the distance is null (screen just behind the aperture) the
shape of the pattern is the shape of the aperture. so we have two operators (Id and... |
For a physics project, I'm planning to investigate the relationship between the number of slits in a diffraction grating and the intensity of the central maxima. The light meter which I'm planning to use to measure the intensity gives me a result in LUX.
I know the wavelength of the red laser light which I'm using is a... |
Does anybody know where to find the erratum page for Arfken, Weber, and Harris' Mathematical Methods in the Physical Sciences seventh edition?
In Arfken, Weber, and Harris' Mathematical Methods in the Physical Sciences seventh edition, the Fourier transform is defined on page 966 as:
$$g (\omega) =\frac{1}{\sqrt{2 \pi ... |
There are on this site a few questions about photons and circular polarization, but none of them give satisfactory answers:
Connection between spin angular momentum of a photon and circular polarization of light
I have read this question:
What does a circularly polarized electromagnetic plane wave look like in a co-rot... |
I have this thermodynamic problem in one of my chemical engineering class:
''The R-410A refrigerant is contained in a single piston / cylinder arrangement. temperature of 20 C and a titer x = 1. An expansion which can be described by the following mathematical relation: P = C/v (v is specific volume) where C is a cons... |
In textbooks the trajectory of a single particle is always shown, but in real life is a single particle or a beam of particles used?
|
When an electromagnet is connected to a circuit, the electric current does not reach the required strength immediately, but gradually. Why?
When the battery terminals of the flashlight are briefly connected and turned off, we notice a spark. It is much stronger if an electromagnet is connected to the battery. Why?
You... |
I don't know if this is right, but I think that it is because:
when the gas is heated, the electrons get 'excited' and move up to an energy level (lets say an electron moves up 4 energy levels).
Then as they move down, they emit all 4 photons of different wavelengths which are then shown on the emission spectrum.
wh... |
I built a coil that receives magnetic fields (Rx) from a sending coil (Tx) a few centimeters away. (wireless power transfer) I send waves to the Tx at the Rx's resonant frequency since its a loop with a capacitor in parallel. (RLC circuit) Wave sent to the Tx is in the 200kHz range so no impedance matching
Im testing... |
I am beginner and newly started running DFT calculations to find out electronic band structure of certain materials in Quantum Espresso.But we have to select the pseudopotential for running scf loop. There are lots of pseudopotential files(.UPF format) available on the internet for same material. Which is quite confusi... |
Why do we use Ricci scalar in the action equation for the spacetime? Why don’t we use other functions? Is it just intuition? What forces us to use that?
|
Just a thought, but could you have a car but the wheels are balls, then the car goes forward when you shift the centre of gravity of the balls to towards the front of the car, making them roll forward and with them the car and you, no matter the weight of the car. If so, you could power a car with 9v (powering the serv... |
Problem: Consider a spherical shell of radius R centered on the origin. The top-right quadrant ($0<θ<90$
degrees, $0<φ<90$ degrees) is at a voltage V. The rest of the sphere is grounded. Determine the potential at the origin.
I am trying to solve this problem using Green's Functions.
For a sphere, $$\phi = \frac{1}{4\p... |
As there are types of forces such as Normal, Tensional, Gravitational, etc.
Suppose a block of mass $m$ kept on a table and a man is pushing it and a acceleration $\vec{a}$ is produced.
Is $m\vec{a}$ really a force? If yes, then please tell what would be it's type?
|
Stretching across China, from the Xinjiang region in the west to the province of Anhui in the east, there's a ±1,100 kV high-voltage direct-current transmission system. I'm not 100% sure what "±1,100 kV" means, but I think it means that the system uses two conductors, one with a voltage of +1,100 kV relative to ground ... |
Ernest Rutherford proposed that the electrons were orbiting around the nucleus just like planets orbiting around the sun. However, this simple picture defied the laws of physics. Electrons revolving around the nucleus would lose energy and spiral into the nucleus, i.e. the atom would collapse.
The above is a passage ... |
Consider a sphere embedded inside of an infinite elastic and isotropic medium. If a force $F$ is applied to the ball from a distance (e.g. via a magnetic field), then the ball will in turn apply a force to the surrounding medium. This force acts in 1 direction only (let's say the $z$ direction).
How do I calculate the ... |
It seems that entropy of a system is related to the fluctuation in total energy due to exchange with the environment. But in an isolated system, there can't be any fluctuation, which would imply zero entropy. Is this correct?
In detail, in Susskind's lectures on Statistical Mechanics, he derives the Boltzmann distrib... |
When pointing my presentation laser at a semi glossy object like stained wood or my skin I see noise, almost like TV static (it also appears to be moving). Is this a property of the laser's refraction on the object? or something with the eye?
|
My question is what makes a conductor able to pass electricity? I know that conductors have free electrons where as insulators don't have as many but can't you just add free electrons to the insulator from a battery or other source?
I know that valence bands are the outermost 'ring' of electrons. In a conductor the ele... |
I have seen a couple of examples of overflow/underflow weirs being used in an aquarium to simultaneously filter surface scum and vacuum debris from a bare bottom tank. I am trying to figure out how much flow I can expect through the underflow vs. the overflow depending on configuration.
Here is a diagram of what I am ... |
In Poincare group, we consider mass as a Casimir of the group. Hence it is a constant in various frames (I do not mean old fashion Lorentz transformation). But, in the quantum field theory mass is the coefficient of the field square term, and could be considered as a coupling constant.
What is the relation between thes... |
I'm trying to find any of these references below.
I. D. Yaroshetskii and S. M. Ryvkin, in Problems of Modern Physics (in Russian), ed. V. M. Tuchkevich and V. Ya. Frenkel (Nauka, Leningrad, 1980), pp. 173-185 [English translation: Semiconductor Physics, ed. V.M. Tuchkevich and V.Ya. Frenkel (Cons. Bureau, New York, 19... |
Let's imagine we have a long lever fixed to the ground at one end by a hinge. We lay this lever across a scale with the scale placed a distance d1 away from the hinge, then tear it. Then a person stands on the end of the lever opposite from the hinge, a distance d2 away from the scale.
... |
(e.g., longitude/latitude, elevation, and Earth’s mass and rotational speed)
I know a couple of approximations for the gravity due to Earth’s mass. The usual one I’ve been given is $g \approx 9.8 \, \mathrm{m / s^2}$; and there is also a generic equation for any two objects with mass, $F = G \frac {m_1 \cdot m_2} {r^2}... |
Version 1:
An infinitesimal variation on the fields $\phi\mapsto\phi'$ is said to be a symmetry if $\delta \mathcal{L}:=\mathcal{L}(\phi',\partial\phi')-\mathcal{L}(\phi,\partial\phi)$ is a total derivative $\partial_\mu F^\mu$. If this is the case, let $\phi'(x)=\phi(x)+\delta\phi(x)$. Then
$$0=\delta\mathcal{L}-\part... |
I have read about this: Essentially in an insulators there is a big energy gap between the (valence) and the conduction band which is why there aren't many free electrons in a insulator. How does this relate to an insulator not being able to transfer electricity? Can't you just plug a battery into the insulator thus c... |
Consider an impedance $Z$ on a waveguide of impedance $Z_0$. I add a load $Z_L$ at the end of the line but I don't think it should enter in the calculation ?
I call $1$ the left port, $2$ the right one. I can define four voltages:
$V_1^{\leftarrow}$, $V_1^{\rightarrow}$ are the reflected and incoming voltages on the l... |
For electron-positron interactions, we have different cross sections, depending on the available reaction energy. To get an overview how many particles of a certain type have been created, we can calculate cross section ratios, f.ex. \begin{equation} R_{had}=\frac{\sigma \left ( e^-e^+ \rightarrow \text{hadrons} \right... |
I'm misunderstanding something very important regarding magnetic force and its relation to velocity.
According to the Lorentz force, the magnetic force ${\mathbf {F_B}}=q{\mathbf {v}}\times {\mathbf {B}}$. Assuming the charge is not moving, then ${\mathbf {v} = \begin{pmatrix}0&0&0\end{pmatrix}}$. Therefore, ${\mat... |
Good day. This is my first post and I was not sure whether to post here or on Math StackExchange. Since the end product of my goal results in ultimately understanding some basic math in physics, I decided to post here.
Graduated HS in '95 and did not take any upper level math. I did take 'College Algebra' in Community ... |
If an average person can lift say 100 lbs alone, how many pounds can he lift with a friend (the same size)? I've heard each person can lift 3 times his usual amount when with another. Is that scientifically proven and why?
|
I need to describe the relative magnitude of a force using real-life comparisons instead of numbers.
I work in engineering, we install some Devices on a flat surface and my task is to periodically check how stable the Devices are. Specifically, I push them with my hand to see if they will tilt, spin, rock or move. I no... |
Let suppose a satellite revolves around the earth. Air pressure inside the satellite is maintained at 76 cm of mercury, and i have a barometer of length 1 m initially
as in space the gravity is zero and hence to equalise the pressure at the free surface of reservoir of mercury, the mercury in column has to rises upto 1... |
I have two questions:
Let us imagine that we have an integer quantum Hall system with electric Hall conductance as $\sigma_\text{H}$ on a two-dimensional (spatial) torus with size $L_1\times L_2$. If we uniformly insert a unit $2\pi$-flux into the torus (which is the minimal flux on a torus allowed by Dirac's quantiza... |
I have a system of $N$ fermions that can occupy $M$ single particle states, and $M$ is much larger than $N$, $M \gg N$. Since only a single or no fermion can be in a particular state, the number of way of counting the number of states for indistinguishable fermions is going to simply be ${M \choose N}$. This means that... |
So today I was solving a problem from my book. I even did not understand it. I saw the solution but even did not understand the solution, The question is,
"In 1959 Lyttleton and Bondi suggested that the expansion of the Universe could be explained if matter carried a net charge. Suppose that the Universe is made up of... |
I do not understand why the partial derivative of y with respect to x is
$\frac{F_{1}}{F_{t}} = \frac{-dy}{dx}$
Shouldn't the partial derivative of y w.r.t x = 0?
|
In the Figure below assume the magnetics are shaped such that the magnetic field is in
the $z$ direction and varies as
$$
B_0 = B_m\left(1-\frac{x^2}{a^2}\right)\hat{z}
$$
Find the emf in the loop by two methods, a) the rate of change of flux b) the motional
emf method.
My try:
$$V_{emf} = -\int B \cdot \frac{\partial ... |
I have read that hurricanes spin because of the Coriolis effect. Since the Coriolis force is a ficticious force, which is only present in a frame that is rotating w.r.t. to an inertial one, I am wondering if an inertial observer would have an explanation which does not rely on ficticious forces.
|
Let try an experiment.
If water enter through an end $A$ with some velocity say $v_1$,and leaving end $B$ with speed $v_2$ in a UNIFORM cylindrical tube $AB$ (which is completely filled with water).
If we consider 3 cases.
tube is horizontal
tube is vertical with $A$ upward
tube is vertical with $B$ upward
And we go ... |
I was working with a derivation of Maxwell-Boltzmann statistics occupation probability today and I got this problem with the constraints:
We know that the particle number is conserved when we are increasing the value of $N_i$ by a little amount, so we write that, $$\sum_{i}^{N}\delta N_i=0$$ where $N$ is the total numb... |
I get that $S_z$ operator has spin $\frac{h}{2\pi}$ ,$\frac{-h}{2\pi}$ because the spin angular momentum along the $z$ direction is the latter. But why should this be the same even for $S_x$. Can you explain the intuition?
|
Let $(Q,g)$ be a Riemannian manifold and let $q_0,q_1\in Q$ be two points that are joined by a unique geodesic $\gamma$ (this holds in particular if $q_1$ belongs to a normal neighborhood of $q_0$). Suppose that $q_0=\gamma(t_0)$ and $q_1=\gamma(t_1)$, then we define Synge's World function as
\begin{equation}
\labe... |
What explains this asymmetry between the electric and magnetic fields if both electric and magnetic monopoles exist? Can't Maxwell's equations be formulated to be symmetric between the two in the presence of both monopoles? What leads to magnetic monopoles existing before the inflationary epoch and becoming infinitely ... |
I've read this in a book
When air is heated in an open vessel, pressure is always atmospheric pressure, and volume of the gas is constant.
How is volume of the gas constant in this case?
|
I was shown this derivation for the gravitational potential energy, and I'm not very happy about it assuming that $\frac{1}{\infty} = 0$. Is there a better derivation, either using a completely different method, or one similar that avoids $\frac{1}{\infty}$?
\begin{align}
\text{work done} &= \int F dx\\
&= \int_{\infty... |
I am studying the notes on susy qm of David Skinner (http://www.damtp.cam.ac.uk/user/dbs26/SUSY.html) (which itself follows the mirror symmetry book by Vafa and Hori (relevant pp. 206 - 210)) and had a trouble with the footnote on p.45 in chapter 3 which suggests that one can obtain the canonical commutation relation f... |
I am trying to show $\displaystyle{\not}{\nabla}^2=\nabla_{\mu} \nabla^{\mu}+R/4$ where $R$ is Ricci scalar. $\nabla_{\mu}$ is covariant derivative for spinor:
\begin{equation}
\nabla_{\mu}=\partial_{\mu}+\frac{1}{2}\omega^{ab}_{\mu}S_{ab},~~S_{ab}=\frac{1}{4}[\gamma_a,\gamma_b]
\end{equation}
and
\begin{equation}
\di... |
A cone of height $h$ and base radius $R$ is free to rotate around a fixed vertical axis. It has a thin groove cut in its surface. The cone is set rotating freely with angular speed $ω_0$, and a small block of mass $m$ is released in the top of the frictionless groove and allowed to slide under gravity. Assume that the... |
At the end of class, my physics professor left us with a question:
"Why turning the wheel of a static car is much harder than turning one in motion?"
I took the wheel to be a little wide and have a little compressibility so the area of contact would make a rectangle.
Now in the first case turning is opposed by frictio... |
We have a mass sustained by a spring $K$ and a damper $C$, with a base excitation. Let's call $s(t)$ the base excitation and $x(t)$ the mass motion.
The differential equation of this system will be:
$m \cdot \ddot{x} + C \cdot (\dot{x(t)} - \dot{s(t)}) + K \cdot (x(t) - s(t)) = 0$
Suppose that $C$ is not a constant, bu... |
Two identical containers kept at the same temperature carry the same gas with different molecular mean free paths l1 and l2. the gas from the first container is completely transferred in to the second container at the same temperature. What is the molecular resultant mean free path in the second container?
Does it hav... |
Why is it recommended to lower the pressure of tire when going through sand?
please help me I have tried very long thinking
this question is from my textbook but no answer
|
It is said that there are detectors that can detect the impact of a single charged particle in transmission electron microscopy (TEM) that do not rely in the conversion of electrons into photons. In this manner, a single electron seem to act as a solid particle.
Assume we have a smooth glass incline plane in a vacuum s... |
We can express any desired periodic waveform using Fourier series.
In the book I am studying from it's said:
'We see that with Fourier series, we can produce any desired periodic waveform and extract its wave number content (via the $a_n$ and $b_n$). But even though we have used an infinite number of plane wave compon... |
Since net force on a massless spring is zero, work done on a spring should be zero, according to elementary work done $F \cdot dr$ since
$F= 0$. Then why do we calculate it to be $\frac {kx²}{2}$?
Please help me.
|
Firs this question has some similarity with Bond order correlation function and Bond Orientational Correlation Function - how exactly to calculate but its a little bit different , so having those context i am going to evaluate the bond orientational correlation function which has the form $$g_6(x=|x_i - x_j|) =\langle\... |
In non-degenerate time-independent perturbation theory we see that the second order correction to the eigenstate energy exhibits 'level repulsion'.
Is this a purely mathematical curiousity or is there physical intuition that can be gained here?
|
One can cover circular motion with different speeds at different positions, right? The only aim is to complete his circular motion, right?
|
Is partial pressure the actual pressure a component contributes in a mixture? What is the physical essence of partial pressure?
|
I've just started studying Physics and I'm not sure how you're supposed to calculate the time constant of a capacitor when a direct current is applied. DC means that frequency equals = so the resistance is infinite, but you need a value for the resistance to use the formula tau = RC. I just did the experiment so I know... |
The DeWitt ansatz for the heat kernel is given by
$$K(t ; x, y ; D)=(4 \pi t)^{-n / 2} \Delta_{V V M}^{1 / 2}(x, y) \exp \left(-\frac{\sigma(x, y)}{2 t}\right) \Xi(t ; x, y ; D)$$
where $\sigma$ is the Synge's world function, $\Delta_{V V M}$ is the Van Vleck-Morte determinant. Due to the heat equation
$$(\partial_t + ... |
Some time ago the remnants of a collision between two collections of stars were discovered. These remnants are called the Bullet Cluster:
The color blue (non-visible in reality) represents the presence of dark matter. Pink represents the normal matter (I'm not sure if the color pink in this picture is actually visible... |
Suppose a small block and using my hand I push it. Let's say the block had some mass $'m'$, and, say this block builds up an acceleration of $a$ when my finger accelerates at a rate of $a'$ and finally let $M$ be the mass of the region of my body which would exert force.
By the third law,
$ ma= Ma'$
But what is $M$? Wh... |
For example, the dimensions of the universal gas constant come close: only luminous intensity and current are excluded.
$$ \mathsf{M} \mathsf{L}^2 \mathsf{T}^{-2} \mathsf{\Theta}^{-1} \mathsf{N}^{-1} $$
Is there any derived quantity that is expressed in all seven fundamental quantities?
$$ \mathsf{M}^a \mathsf{L}^b \ma... |
I am trying to follow Peskin & Schroeder's textbook on Renormalization. I tried a few ways but this does not match with the textbook.
First equation (10.43 )in Peskin is given
\begin{align}
\delta_2 = -\frac{e^2}{(4\pi)^{\frac{d}{2}}}
\int_0^1 dx \frac{\Gamma\left(2-\frac{d}{2}\right)}{\left( (1-x)^2 m^2 + x
\m... |
I'm mainly focused on Computer Science, but I am trying to create one simulation where I need to resolve collisions between points with mass and absolute velocities.
Imagine having:
$point = <v_x, v_y, m>$
$v_x$ is velocity in x axis,
$v_y$ velocity in y axis
$m$ is mass
we have two points that we know, that they are ... |
Let's say we have a body of spherical shape with a temperature T > 0 Kelvin for our purposes.
It's supposedly in empty space. Completely empty space, no other radiation, no far away stars nothing.
So this body will be radiating EM waves of some wavelength related to it's temperature with most of the around a wavelength... |
Since we know that when we watch a star, we are watching it in a state it was before when the light started travelling from it. So suppose, I travel from Earth to a distance of 1 light year and than watch back at Earth, what Earth will I watch, the present Earth or the Earth 1 year in the past?
|
I'm trying to understand this paper1, in particular the remark after Eq. 26.
Let me rephrase the problem. According to the paper, one can write the Berry phase as
$$
\theta_B=i\oint_\Gamma\frac{1}{C}\frac{\partial C}{\partial w_k} \mathrm{d} w_k +c.c.=i\oint_\Gamma\frac{\partial \ln C}{\partial w_k} \mathrm{d} w_k +c.c... |
I have been doing some thinking about the Einstein Equivalence Principle (EEP) and its formulation, namely:
The outcome of any local non-gravitational experiment in a freely falling laboratory isindependent of the velocity of the laboratory and its location in spacetime.
After some time it came to mind the following ... |
As the title states, I'm unsure what it means to be a commensurable or incommensurable grain boundary (when discussing dislocations and small angle grain boundaries). I see the term being used throughout literature.
Any help would be much appreciated.
Side question: are the terms commensurate and commensurable the same... |
Can someone explain me in simple terms where and what are the magnetic, geographic and geomagnetic poles?
Some sites say that magnetic north pole is in the south and thus it attracts the south pole of the magnetic needle while some say the north pole of the needle points south. In each place, I seem to get a differen... |
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