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According to https://en.wikipedia.org/wiki/Planck_units, the Planck area is defined as the square of the Planck length, and the Planck volume as the cube of the Planck length.
\begin{equation} l_\text{P}^2 = \frac{\hbar G}{c^3} \end{equation}
\begin{equation} l_\text{P}^3 = \left( \frac{\hbar G}{c^3} \right)^{\frac{3}{... |
Thermocouples work on the principle of the Seebeck effect. In the simplest one-dimensional form, the voltage appearing between two points on a conducting solid having a temperature difference of $\Delta T$ is given by
$$\Delta V=S\Delta T$$
where $S$ is the Seebeck coefficient. If we have a junction between two conduct... |
Suppose we have a source which can repeatedly create an $n$-mode Gaussian state with covariance matrix $\sigma$. How can I use homodyne measurements to completely determine $\sigma$? If the quadratues are $\left( \hat q_1, \hat p_1, ..., \hat q_n, \hat p_n \right)$, then assume that the first moments $\langle \hat q_i ... |
I encountered a Homework like question. However, I am not interested in the solution as such, but rather, in a specific concept. My question is related to the following post (HOMEWORK: Minimum angle to start the mop moving), but I do not quite get how is the magnitude of the force being positive is connected to the min... |
I have read to Sean Carroll that he says that the Big Bang model is correct, but the Big Bang event is incorrect, so what is the difference? And everyone knows that the Big Bang model is linked to the Big Bang event, which is the singularity, so how can there be a Big Bang without the singularity?
The Big Bang “model... |
Currently the proven theory is the quantum field theory. This theory defines fields in "all spacetime" and particles are disturbances in these fields. These particles are punctual and interact through virtual particles.
But string theory is not clear to me. This defines the strings (bosonic or fermionic) as the smalles... |
Why does the term $\frac{i\hbar}{2}\log\det\left[\frac{\delta^2S}{\delta\phi^2}\right]$ in the expansion
$$\Gamma[\phi]=S[\phi]+ \frac{i\hbar}{2}\log\det\left[\frac{\delta^2S}{\delta\phi^2}\right] +…\tag{1}$$
give only 1-loop contributions and no 2-loop? Or is this simply because we have only 1 trace?
|
I know of only two instances where the infinite square well is an adequate model for experimental behaviour: the absorption wavelengths of cyanine dyes, and extremely small semiconductors to which electrons are confined, i.e. "quantum dots".
(This previous StackExchange answer mentioned quantum lasers, but wasn't quite... |
I know this is the correct formula for the action for a arbitrary $p$. I know how to obtain the equations of motion for $p=1$, but I struggle to find a way to do this with an arbitrary $p$. I also know what the correct equations of motion are:
[]
I got the first one, but struggle to get the second one. How can I inter... |
An ion is shot through two grids, one positively charged, the other negative. The positive one has much more charge than the negative one. Let's hypothetically assume both grids have zero applied voltage: their charges aren't moving at all (so no power would be needed, since P=v·I, if voltage is 0, power is 0).
Does t... |
The Novikov self-consistency principle prevents a paradox in which a billiard ball is sent to its past through a closed timelike curve (allowed under general relativity) such that it collides with its past self and prevents it from entering.
Imagine a setup where the ball, as soon as it exits in the past, hits a switch... |
What exactly do astrophysicists mean when they say that the universe is expanding at an accelerated rate? Assuming that the universe is a sphere, do they mean that the radius of the universe increases exponentially, or do they mean that the volume of the universe increases exponentially? Or is it that the universe is n... |
Physicist Grigory Volovik has put forward some ideas about the universe undergoing a topological phase transition (especially in the early stages of the universe). He published a book called "The Universe in a Helium Droplet" where he explained his ideas. You can find a brief discussion about it here.
In one discussion... |
I am looking to combine the principles of spallation neutron sources, wakefield particle accelerators, and neutron absorption to enable anybody to create large amounts of plutonium using relatively abundant uranium-238.
Thanks to the strong neutron flux of spallation neutron sources, I believe that the neutrons will be... |
We know that thermal radiation is one of the ways energy can be transferred from one object to another.
And we know, objects at any temperature emit electromagnetic radiation.
So does that mean molecules and atoms are constantly losing energy?
And why isn't this considered in the first law of thermodynamics?
How can we... |
I was wondering if we could use background radiation to produce electricity (even a tiny amount). However, I've read somewhere that solar panels absorbing infrared (and lower frequencies photons) wouldn't be very efficient, as they are limited by the laws of thermodynamics. The arguments states that the panel needs to ... |
This Mathematica.SE question https://mathematica.stackexchange.com/q/284679/ is physical too, so I have decided to duplicate it here.
I have a set of anisotropic gaussian basis set which describes the ground state of the system with great accuracy.
The Hamiltonian of the system has the following form: $$H=-\frac{1}{2}\... |
Not that I work in this field, but I have heard the discourse from several people that string field theory is useless.
So I would like to ask two simple questions?
What makes SFT so difficult? Especially, it seems to me that one can construct an action that satisfies general coordinate transformation invariance and ga... |
I am trying to understand a sample circuit in this explanation of an SR latch: https://youtu.be/KM0DdEaY5sY?t=102
Let us assume that the system started in a position where all inputs and outputs are "zeros". Once we enable power on input "A", output "OUT" is powered on and fed back into the input "B". Once we remove p... |
I see that electrons are quite small in size, moreover it is moving fast but I have a question why do free electrons not leave a conductor (like a wire) ? but they can only move at the edge of the conductor?
|
In GR the (perturbed) metric obeys a wave equation in a certian gauge. The same thing happens EM waves, $\Box^2A_{\mu}=0$ only on a certian gauge, but $\Box^2F_{\mu\nu}=0$ without fixing the gauge.
I believe the reason this is not a "problem" is due to the potential not being observable, while the field are.
In the ana... |
In this image, power is used to apply voltage to the charged grids.
But if no voltage is applied, would ions still be accelerated by Coulomb forces to create thrust? If not, why?
|
The derivation of the Casimir effect in $1 + 1$ approximates, say, the left mirror and the asymptotic "in" region of spacetime as two fixed mirrors separated by a spacial distance of $L \to \infty$, with the resulting modes of the free scalar quantum field being of the form of standing waves. The right mirror is then a... |
In the Casimir effect, after performing the regularization, it is found that the zero point energy between two conducting plates in a distance $L$ from eachother is (in the 1D case),
$$E=-\frac{\hbar c \pi}{24 L}.$$
From this result, it is argued that the force felt between the two plates containig the quantized modes ... |
I am now studying QFT using Schwartz's book, and I am going through the part discussing about how the charge conjugation, parity, and time-reversal operator acting on various object should look like. He starts with how charge conjugation operator on the spinors act:
$$C : \psi \rightarrow -i \gamma_{2} \psi^{*}$$
and t... |
This is a question about conservation of momentum. Will the inertia of the rotating pencil make the pencil bounce higher? Both cases the pencil is dropped from the same height but the spinning pencil is made to spin by a force couple besides being dropped.
|
The Berry phase is defined as the phase acquired by the wave function of an electron when passing along some closed contour along the Brillouin zone.
In the case of topological materials and, in particular, Dirac semimetals, it is equal to $\pi$ , when an electron bypasses the Dirac point.
But what physically means tha... |
The Novikov self-consistency principle prevents a paradox in which a billiard ball is sent to its past through a closed timelike curve (allowed under general relativity) such that it collides with its past self and prevents it from entering.
Imagine a setup where the ball, as soon as it exits in the past, hits a switch... |
I'm working through Taylor's Mechanics and he seems to assume this implicitly at a few points. Intuitively, I agree that this should be the case. For while at any time during the rolling there ought to be a force of friction acting on the point of the object in contact with the surface, this force never "acts through a... |
I know that this may be a duplicate question but wait, I want to analyse the phenomenon from a different perspective.
For a conducting plane sheet of charge
There should be positive charge at both end so that the electric field at point P1 is cancelled out and thus field inside conductor is zero!
However, in this cas... |
Suppose $A$ is a null $4$-vector in Minkowski space-time, $M$. Then the vector space spanned by $A$: $\operatorname{span}(A)$ is unidimensional. The orthogonal complement of this vector space $\operatorname{span}_\perp(A)$ is in fact the same vector space since the only $4$-vector orthogonal to a null vector is one tha... |
Often we define a quantum phase of matter as a set of ground states of a gapped family of Hamiltonians, where the gap does not close anywhere in the family. Equivalently, we can define it as a set of states which are related by constant depth quantum circuits with local gates (equivalence of these two definitions is sh... |
The textbook I am currently using states that when all quarks have the same flavor, there are no $J=1/2$ baryon wavefunctions for the ground state $l=0$.
Is this an experimental result or is there a theoretical reason for this?
|
In the context of Phys. Rev. A 104, 022401 (arXiv:1803.10710), Figure 3
What happens when a maximally entangled state( not $k$ extendible even for $k=2$) passes through a $k$-extendible channel? We know that a $k$ extendible channel preserves $k$ extendible states.
What role do $k$ extendible channels play in entangl... |
I'm having trouble understanding what the paradox is in the Wigner's friend thought experiment. I've read a number (but not all) of the other questions about Wigner's friend here on this site although none of the ones I read seem to address the source of my confusion:
It seems to me that there is no paradox, because th... |
I am self-studying Griffiths' Electrodynamics. I am on a section about basic properties of conductors. My question is about electric fields and electric potential for a conductor with a cavity inside.
My question is based on a problem in Chapter 2 of the book, which is as follows
2.38 A metal sphere of radius $R$, car... |
If I have a fluid in motion at a given time and I know its pressure $p$ everywhere, I know its dynamic viscosity $\mu$ and I know its velocity field $\vec V$.
This system must hold some intrinsic potential energy $E$.
I know that in a fluid at rest the pressure is a measurement of potential energy, so if the fluid is e... |
Consider a container of ideal gas divided in half by a partition where each half is at the same temperature, pressure, volume, and number of moles. In my statistical mechanics class we have gone over the Gibbs paradox / mixing paradox and so I know that, if the particles are indistinguishable, the entropy increase from... |
according to Lorentz oscillator model that describes optical responses of materials we get a complex permittivity which its real part is given by
we can see that the real part converges to 1 at high frequencies , now I plotted the function of the real part at different plasma frequencies (other constants didn't chang... |
I'm wondering what would be observable to an astronomer if one knew where to look for a distant space craft with a powerful ion engine such as a Dual-Stage 4-Grid (DS4G) electrostatic thruster. In the near future I suspect these to be used by drones and probes and I wonder if you'd need an observatory or just a nice te... |
I've read several threads over the past several days talking about how photons don't have wavefunctions in the same way as massive particles do because they don't have non-relativistic limits. If I understood correctly, that's because the usual position operator introduced in introductory QM courses really only applie... |
Given the heat equation $u_t=\alpha^2u_{xx}$, an initial distribution $f(x)=u(t_0,x)$, and the solution using Fourier series of $u(t,x)$
$$u(t,x)=\sum_{n=1}^{\infty}D_n\sin\left({n\pi x\over L}\right)\exp\left(-{n^2\pi^2\alpha t\over L}\right) $$
I understand that the average temperature should be constant if I'm corr... |
This is a follow-up question to my earlier post. The Schwinger–Dyson equation on Peskin and Schroeder reads (p.308):
$$
\left\langle\left(\frac{\delta}{\delta\phi(x)}\int d^4x'\mathcal L\right)\phi(x_1)...\phi(x_n)\right\rangle = \sum_{i=1}^n \left\langle\phi(x_1)...(i\delta(x-x_i))...\phi(x_n)\right\rangle \tag{9.88}
... |
A question from Zhangwill:
I understand how to arrive at the "correct" solution. Pictured below. It is illogical (even if it follows from solution) that sigma of conducting planes could have dependance on the position of plane. E due to a plane is invariant under translation. My purposed solution: send interior sig... |
my sir told me that he will get a shock, but why not bird then
he replied bird has legs acting as insulators
i am in confusion what is the right explanation to this
|
Imagine a bead that is fixed on one end of a rod, the other end of the rod is free to rotate about a pivot. If someone taps on the bead, then the bead will start to rotate about the pivot point. There must be some centripetal force on the bead. Where does it come from? I've found some similar posts but most of them are... |
Consider the diffusion equation in an external force $F$ and suppose $\rho$ is the density of a conserved quantity of the system(e.g. particle density), the diffusion equation is
$$\frac{\partial \rho}{\partial t} = -\gamma F\frac{\partial \rho}{\partial x} + D\frac{\partial^2 \rho}{\partial x^2}$$
and the current is
$... |
I've seen several sources stating that Einstein was partially inspired by the Ehrenfest paradox when thinking about general relativity. However in the Ehrenfest paradox the non-Euclidean nature of the space in the rotating frame of reference is linked to Lorentz contraction rather than gravitational forces like in GR. ... |
I learned that for a non-interacting tight-binding system $H=\sum_{n}\varepsilon_na^\dagger_n a_n$, the time evolution of $a_n$ is simply $a_n(t)=e^{-i\varepsilon_nt}a_n$. I tried to prove this:
\begin{align}a_n(t)&=\exp({it\sum_{k}\varepsilon_ka^\dagger_k a_k})a_n\exp({-it\sum_{k}\varepsilon_ka^\dagger_k a_k})\\&=\ex... |
I'm currently studying the two-body decay where a particle (Be) with spin-1 decays into a pion (spin-0) and spin-1 particle $X$. The system is prepared so that the Be is polarized with a spin projection of +1 in the $x$-axis, this led me to conclude that there are two possible decays.
One where the Be-X state has $L=0$... |
For Polchinski renormalisation equation, a smooth cutoff is introduced that is essentially a factor of $ 1 $ up until the cutoff region in the kinetic term. Beyond this "cutting-off" region (where the function is smoothly interpolated) instead of reaching the value $ 0 $, the factor is infinite.
For example the integra... |
In this question, the answer by twistor59 says
by using the exponential map on linear combinations of [the lie algebra basis vectors], you generate (at least locally) a copy of the Lie group.
I'm interested in the details of "at least locally": Given a fixed basis $A_1, A_2, ... A_k$ of the lie algebra, under what co... |
I wanted to generalize the result for the following question for four spins 1/2: Most general form of a spin rotation invariant Hamiltonian?.
Assume that we have a Hilbert space for four spins $(\vec{S}_1,\vec{S}_2,\vec{S}_3,\vec{S}_4)$ and we want to create an object $H:=H(\vec{S}_1,\vec{S}_2,\vec{S}_3,\vec{S}_4)$ tha... |
It says in the group theory that the angular momentum operator of a spin half particle is just half of the Pauli matrices. However, in the quantum field theory, the angular momentum can be expressed as a functional of the field operators based on the Noether's theorem. Are they consistent?
|
Does the phase of wavefunction matter in a numerical calculation?
Recently, I was trying to solve a simple model system using numerical grid-based methods and saw that the phase of the ground state was sensitive to changes in the parameters of the numerical grid. I found that the ground state wavefunction $\Psi_{0}(x_{... |
why we consider the rotational axis of proton under the action of magnetic field in MRI not electron?
|
I'm reading the Griffith, Introduction to Electrodynamics, Third Edition, p.353, Example 8.2 and stuck at understanding some statement. I want to deepen my understanding of electromagnetism, so I ask this question.
Example 8.2. Determine the net force on the "northern" hemisphere of a uniformly charged solid sphere of... |
Context
I was solving questions from the 5th edition of "A Textbook of PHYSICAL CHEMISTRY: Thermodynamics and Chemical Equilibrium" by Kapoor, K. L., which is the second of several excellent volumes the author has published on physical chemistry, where I came across this:
At 263.15, water may exist as a super-cooled l... |
Industrial printing is based on autotypical colour mixing, the simultaneous effect of subtractive and additive colour mixing. This makes it possible to render a large set of colours using only four standardized colours (CMYK):
I do understand additive and subtractive colour mixing but I struggle to understand how two ... |
How to approximate the maximum size of the Coulomb repulsion force between an alpha particle and a gold atom/nucleus for both the plum pudding model and the Rutherford model*
Please could someone explain how to work this out?
|
I am building a robotics college level project, an unmanned aerial vehicle or a drone.
I am using a mpu 6050 IMU for getting instantaneous acceleration and angular velocity of the system.
I will be using dead reckoning for position and attitude estimation.
I wanted to verify if the angular and linear kinematics formula... |
I found this interesting question in a textbook about special relativity:
A length-contracted object has length $L=\frac{L_0}{\gamma}$. Joe differentiates this with respect to time and finds
$$\frac{\mathrm dL}{\mathrm dt}=-L_0 \gamma v \frac{\mathrm dv}{\mathrm dt}$$
He reasons that there is no upper limit on the mag... |
What happens when you try to rotate a system around not it's center of mass?
|
I'm studying the Sherrington-Kirkpatrick model in the book of Nishimori Statistical Physics of Spin Glasses and Information Processing, in particular the SK model and its phase diagram. I report here the specific page:
He says that there is a line which separates the spin-glass (SG) and ferromagnetic (F) phases, as pr... |
Suppose that there is a point light source with power $P$. We are interested in a single light ray visualised in the above picture. The ray travels a distance $r_1$ and encounters a surface. The ray comes in angle $\theta$ and is reflected in the same angle. Some of its intensity of course is lost, say, a proportion $... |
I'm trying to figure the photon spheres out for the Kerr BH. An article on this subject Here
descripes the equation of geodesic deviation as: $$\delta r_n = e^{\gamma n}r_0$$
I don't understand where this is coming from, and I cant find it anywhere in that form. Can anyone elaborate on this.
|
According to the Law of Large Numbers, if I throw a million coins, I expect to observe half of them face head, and the other half tail.
Why doesn’t this apply to (1-dimensional) Brownian motion? A suspended particles undergoes the collision with millions of molecules, at every (infinitesimal) time interval. Therefore, ... |
The simplified $E-k$ diagram obtained from Kronnig-Penney model looks like that:
The bottom curve corresponds to the so-called valence electrons, and the upper curve - to conduction electrons.
But these are simply the allowed states. Kronnig-Penney model doesn't (at least, immediately) tell us that only the bottom sta... |
I am told that the following quantum circuit diagram implements the $Z_0Z_2$ error syndrome, but I don't follow.
I understand error syndromes when expressed in matrix form and how performing $Z_0Z_2|001\rangle=-|001\rangle$ for example can be used to identify single bit-flip errors. But I don't follow how this is achi... |
I understand the one-form symmetry of $U(1)$ gauge theories as related to the conservation of magnetic and electric flux, given by integration of two-form electromagnetic field tensor and its dual, respectively. You don't need to consider quantum field theory to see this conservation law. The magnetic flux conservation... |
So we know that EMF of the battery provides an electric field in the circuit and thus accelerating the electrons inside them, so my question is that lets say if there is a perfectly conducting wire, so there the electric field will continuously accelerate the electrons(as no resistance if there for them to collide and ... |
The classic problem of the electrostatic equilibrium positions of a linear system of $ n $ free unit charges between two fixed charges is well known, here an example with $n = 1$.
Few days ago I found out a nice result going back to Stieltjes and Hasse: if the potential between the two fixed charges is logarithmic, the... |
I am trying to analytically solve the light propagation for the following case:
Starting complex field $E_0$
Fresnel ropagation for a distance $d$ to a lens
Lens applies phase modulation with focal length $f$
Propagation from lens to a target plane for a distance $z$.
All steps individually are clear to me.
I know (b... |
In a p-type semiconductor there are always free electrons due to thermal generation allowing for conduction. But If such an electron falls to a hole, it can no longer conduct.
So shouldn't more holes slow down conduction? If intrinsic semiconductors have many more electrons in the conductive band at any one point in ti... |
(The question is very ambiguous, here is the actual scenario I am talking about. I will rename the question, if its required in future.)
If I am standing still and I produce a sound pulse in direction perpendicular to me, and then I start moving, my sound will move in direction perpendicular to me and reflect back on s... |
We have a conducting rod (lenght $l$) moving with constant velocity $v$, on two symmetrical railings, and and everything is conducting. Rod has some resistivity $\rho$, while railings are purely conducting. Magnetic field applied is perpendicular and constant. We need to find electric field vector inside the rod.
Now I... |
After working with some problems regarding flow, I came up to a similiar problem as the one presented here:
In solving the problem, we assume a laminar flow in steady state.
When using Navier-Stokes equations, to fully determine the velocity profile, I get a differential equation of order two. Meaning I need two bound... |
We know that in an AC circuit, if there is a capacitance current is leading by π/2, so does it mean that when voltage across capacitor is maximum, current through the circuit is 0. And why does this leading our lagging come anyways?
(Aside from the mathematical proof, is there a intuitive way to understand?)
|
Would the positive and negative charges line up on either end of the wire? Or would it induce a current? Or would the wire be unaffected by the magnet?
This was deleted for being a homework question. I'm not aware of any homework questions like this. I thought this up in my own head. (I drew the diagram in a program... |
A sufficiently strong electromagnetic pulse can/will destroy smartphones and computers.
I know somebody who went into MRI machine and forgot a Visa credit card in his pocket. The card was toast and he had to get a new one. A mobile phone in an MRI probably wouldn't fare better.
But a big part of the human body itself i... |
I am currently studying the effect that a massive, uncharged, non-minimally coupled spin $\frac{1}{2}$ field has on the background geometry upon quantization, and compare this with results in General Relativity. I will try to balance the amount of details, as there are way too many for a SE question.
Some useful notion... |
Everything I've read online seems to say/imply that the Pauli exclusions principle only applies to fermions and not bosons.
As I understand it the Pauli exclusion principle arises when the spatial wavefunction is antisymmetric about particle interchange. I also thought that both fermions and bosons can have antisymmetr... |
High energy photons scatter off electrons via Compton scattering. The differential cross section of this scattering is given by the Klein-Nishina formula, which contains within it the classical radius of the electron, $r_{e}$,
$$\frac{d\sigma}{d\Omega} = \frac{1}{2}r_{e}^{2}\left(\frac{\lambda}{\lambda’}\right)^{2} \l... |
I am asking a much shorter, more generalized version of this question in order to gather as much information as possible.
I have two field theories $A$ and $B$ which are equal at classical level: they have the same action up to a boundary term.\
$A$ and $B$ are both "limits'' of a broader theory, on which different c... |
Is there any difference between an axiom and a postulate?
I would say that while an axiom is any proposition fixed as true without premises in a theory, a postulate is (also according with its etymology postulatum = something that is requested) something that is necessary to assume to make a theory fit (also in a conse... |
In principle, a connection is totally arbitrary. Berry connection is not the connection, but rather it is simply a connection that is physically motivated. That is, mathematically, we could connect the U(1)-principle bundle fibers in any sort of way, but Berry connection is special because it yields physical consequenc... |
One of the most fascinating parts of de Broglie's thesis is that, if you have a "hyperplane" wave in spacetime, with a frequency of $\omega_0$ and no spatial dependence in its "rest" frame, for example
$$e^{i\omega_0 t}$$
then in another frame, due to relativistic transformation, it will have a finite wavelength and fi... |
I feel a bit daft asking this but how do you calculate the equilibrium position of a system with a spring (spring constant k1) hanging from the ceiling with a mass (m1) attached to the bottom, and attached to m1, there is another spring with spring constant k2 which is attached at the bottom to a mass m2.
I know how t... |
I am trying to proof Helmholtz’s theorem and I am currently using David J. Griffith’s book on electrodynamics to do this. Within the book’s Appendix B, (I have not finished the book, and am on the last sub chapter of the first chapter, the theory of vector fields) I have read along and understood until, “However, it so... |
I mean, to keep producing the same amount of antiprotons for every proton beam.
If so, what's the maximum total amount of antiprotons that can be produced (not trapped) with a target with a certain size/mass?
I read that in Fermilab for each 200,000 protons hitting, one antiproton is produced (0.0005%). But I don't kno... |
Just a thought from a dream
Since water expands so greatly when frozen could it be possible to freeze the water in a metal cylinder but one side is like a car piston with a very high gear ratio which would be no problem to turn because the pressure the ice builds up which generates electricity to freeze the water again... |
I am trying to figure out a picture of the wave properties of relativistic particle, e.g., particle produced at collider. It seems that the particle detected at collider have well defined momentum and energy.
Suppose a relativistic particle that is initially produced by a source within a distance $R$, and the productio... |
It's been a while since I've studied electrostatics and is my first time posting here, so please forgive me if I'm missing something basic.
According to my reference book, the electric potential of a dipole along its perpendicular bisector is zero. Assuming a point P near a dipole such that the distance between the poi... |
In CERN, 0.0003% of the protons that collide with a 0.01 kg iridium plate result in antiprotons.
Wouldn't increasing the mass of the plate result in a higher collision rate? Wouldn't be proportional?
I mean, I assume that the more iridium, the more protons in the plate, and the more protons in the plate, the more likel... |
Say I have the singlet $|s\rangle = |0\rangle - |1\rangle$ and $m=0$ triplet $|t\rangle = |0\rangle + |1\rangle$ quantum spin states (say in the $S_x$ basis). If all I can do are spin measurements, how can I distinguish these two states? If all I do are measurements in the $S_x$ basis, these two states give identical r... |
Given an appropriate situation, for example, a case where there are 2 grounded conductors (infinite sheet charges), one at $y=0$ and one at $y=a$, and a 3rd conductor (at $x=0$) perpendicular to both, maintained at a potential $V_{0}(y) $, (This is the example situation given in DJ Griffiths 4th ed. Example 3, chapter ... |
Take a cupboard or just a large wooden box. When pushed it a point above its center of mass, the cupboard topples because there is a net torque due to the friction and the force you apply. When pushed at a point below the center of mass, the cupboard does not as the torque due to the friction and the torque due to the... |
I've found this diagram about the conduction band (https://energyeducation.ca/encyclopedia/Conduction_band):
But are there other energy bands over the conduction band? Or is the electron simply kicked out of the solid (and so its energy becomes continuous, not in discountinous band).
|
(Im specifically referring to this video at 12:30)
In Michelson-Morley experiment, one light beam goes perpendicular to the velocity of earth, and other goes parallel to the velocity of earth.
Im really confused about the treatment we give to the perpendicular beam.
Here's what I have understood so far. The ether is at... |
After looking at the derivation of Cauchy's stress formula, stated as:
$$ \vec{t} = \sigma \hat{n} $$
I've reflected upon the derivation and some questions have arised. I state them below:
First of all, why are we using tetrahedrons in our derivation? Are we limited to this geometric shape, or is it just because it's ... |
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