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My questions are the following:
I saw that a field was defined as a correspondence of a vector or a scalar to every point in space. I asked my teacher about this definition, and he told me that there is a better one: “a field is a region in space, where a particle with a certain property (such as being charged or havi... |
In looking for the standing wave equation y(x,t) I seem to be finding two variations.
The first variation is $y(x,t)=2A\sin(kx)\cos(\omega t)$ which I found on Wikipedia and other sites, which has a sine and a cosine.
The second variation is $y(x,t)=2A\sin(kx)\sin(\omega t)$ which I found here (scroll to 1.5.6) and on ... |
In exercise 4.2, "Relativistic Quantum Mechanics" by Bjorken-Drell, an additional term is added to the Dirac Hamiltonian such that new equation of motion is
$$\left(i\gamma_\mu{\nabla^\mu}-e_{i}\gamma_\mu{A^\mu}+\frac{\kappa_{i}e}{4M_{i}}\sigma_{\mu\nu}F^{\mu\nu}-M_{i}\right)\psi(x)=0.$$
The first two and fourth terms... |
I am a high school student and I am very confused in reflection of waves on string. My confusion is : when a transverse pulse on string reaches a rigid end, how is the reflected pulse inverted in terms of forces (i.e dynamically not mathematically). Some people and even my school textbook says that this is due to Newto... |
If yes, exactly how does the surface charge contribute in the dielectric polarization?
|
How can one prove that the Einstein tensor (as it is usually defined in the field equations) is the contraction of the double of the Riemann curvature tensor?
Specifically, I want to show
$$
R^\mu_\nu-G^\mu_\nu = \dfrac{1}{2}R\delta^{\mu}_{\nu}
$$
where $G^\mu_\nu$ is the contraction of the double dual of the Riemann c... |
I read in Ian Stewart's 17 Equations that Changed the World book that Navier-Stokes equation (I know it's not exactly a scientific book, but still, I'd like clarification on what is wrong if it's the case):
$\rho \left( \dfrac{\partial v}{\partial t} + v \cdot \nabla v\right) = -\nabla p + \nabla \cdot T + f$
is an ana... |
Where can I find a copy of the circuit diagram for Sandia Lab's Z-Machine, or indeed for any pulse forming network that outperforms the ordinary Marx bank (if such a thing exists)? Google has let me down in my search for this information. TIA.
|
I am undertaking a module in nanosurfaces and I was unaware that I would require some knowledge in Crystallography. The information that I must know regarding this area are Miller indices, Symmetries, Bracket conventions, so that I can answer some example questions such as:
sketch for a face-centred cubic structure th... |
I know conductivity increases, but what happens to the electrons on the inside?
|
I have been studying relativity for a while now, but I am still unsure what the equation is to determine a gravitational time dilation. I am more than aware of the speed time dilation equation, but I would like the gravitational one.
|
"Because when the box is in thermal equilibrium, there can never be any electric field at the walls for it would shake the charge in the wall around, changing the temperature, contradicting the claim that the box is in thermal equilibrium."
This argument just doesn't sit right with me. Thermal equilibrium does not mean... |
Suppose the electric and magnetic fields $e(x)$ and $h(x)$ with units $\left[\frac{V}{m}\right]$ and $\left[\frac{A}{m}\right]$ and their Fourier transforms $E(k)$ and $H(k)$ with units $\left[V\right]$ and $\left[A\right]$. Let's assume that the electric and magnetic field are perpendicular to each other, then the Poy... |
It is known that its zero-energy value is the fine-structure constant α, about 1/137.036.
Various sources state that the running value is in the 1/129-1/127 range at the Z-boson energy (91 GeV). What should be the value at the electroweak symmetry breaking scale?
|
After, in the $S_z$-basis $|S_{z,\pm}\rangle$ denoted by $|\pm\rangle$ and in units $\frac{\hbar}{2}$, finding the spin operator in a general direction $\vec{n} = (\sin\theta\cos\phi,\sin\theta\sin\phi,\cos\theta)$:
$$\hat{\vec{S}}\cdot\vec{n} = \sin\theta\cos\phi\begin{bmatrix}
0 & 1\\
1 & 0
\end{bmatrix} + \sin\theta... |
We say the gravitational PE of a system is $-GMm/r$. This is for a constant gravitational field. But, when we try to calculate PE for a two-body system, the distance the body moves is not the same as in the first case, since the second body is also moving. This creates a changing gravity field. In this case, how do we ... |
When do you use the material derivative, in the Eulerian point of view when looking at a constant position in space, or in the Lagrangian point of view, following a particle?
Since I saw that another name for the material derivative is the "Lagrangian derivative", things have gotten quite confusing.
|
I'm trying to solve a problem but I don't know even where to start.
The problem is about a smooth hollow cylinder of mass $M$ rotating about an axis in one of the extremes of the pole with an initial angular velocity of $\omega_0$. Inside of that cylinder there's a particle of mass $m_1$ that can move freely along the ... |
I am reading Wick theorem from "Student Friendly Quantum Field Theory" By Robert D. Kaluber. I understand how normal orderd vanishes and only contraction remains. But in page no. 205, it is stated that when $t2>t1$, then by the definition of normal order, we always put annihilation operators are always on right side of... |
Disregarding all the problems except the last one. The last problem seems complex for me. A closed curve means that the motion is periodic so that at certain time T ,z spirals backs to it original position and $$\phi(t+T)=\phi(t)+2n\pi\;\;with\;n\;being\;integer$$
$$z(t+T)=z(t)$$
Using this kind of technique will invo... |
When a body is lying on the floor, the following is true.
The maximum static friction is Frmax=μ*Fn, where Fn is the normal force and μ the static friction coefficient.
If a force F1 is applied to the body in a first direction, the body will move if F1 is bigger than Frmax.
However, what happens if the body is not lyin... |
I’m looking for the most up-to-date information about the density parameter (i.e., the density of the universe relative to the critical density). As a layman, I don’t know how to navigate the relevant literature. Hence, I would like to ask if someone here could provide me with some references.
I’m looking for some fair... |
Hypersurface and geodesic can, in principle be written as function of spacetime co-ordinates but not all of them can be written as a polynomial therefore my question is: does algebraic geometry finds any usage in general relativity and if it does how?
My question arose after seeing this DeWitt paper.
|
I am reading the paper 'Coherent Quantum Feedback ' by Seth Lloyd, which unfortunately is paywalled. In Section (IV. A) he states that, for a quantum system consisting of a single spin in an NMR setup, the two Hamiltonians $B \sigma_z$ and $B_x \sigma_x\text{sin}(\omega t)$ 'can be easily seen to generate the full alge... |
If you put 1 room temperature soda in the fridge, will it take longer to chill than if you put 2 in the fridge, or will the 2 chill faster, or does not make a difference? I guess, does the inherent heat of the pre chilled sodas hinder the chill rate of the others?
|
Hi I was wondering why would a secondary cell have a lower internal resistance than a primary cell. I had read somewhere it was due to the fact secondary cells used lead acid which has a lower resistance but I was hoping to get more information on it.
|
While solving this problem that I have mentioned in a post in math stackexchange.I ran into a differential equation not solvable by elementary methods.I just wanted help, to check if my equations are correct.
Here is the link to the post.
Please correct my misunderstanding if there is any.
If possible I would also app... |
How do I calculate the effective resistance of this circuit?
Using only the two formulas:
$$\frac{1}{R_{Total}}
= \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} + \cdots$$ and $$R_{Total} = R_1 + R_2 +R_3$$
I know how to calculate current and voltage using the node voltage method and thus derive the resistance. but I'... |
I have difficulties understanding the following (Everything out of the book Gravity by Poisson and Clifford): We have a quantity $\mathfrak{g}^{\alpha \beta}$ called gothic inverse metric in prior unspecified coordinates. Then we impose the four harmonic coordinate conditions $\partial_{\beta}\mathfrak{g}^{\alpha \beta... |
When we place an object above mirror and viewed from side, we see the image to be below the object, as if the reflected light is coming from inside the mirror.
From the image above, the light from top gets reflected in front of object. So comparing the image and object, they are perpendicular to each other. But our br... |
I have been using a formula to calculate how much heat needs to be generated by a pipe in order to raise the temperature of the water flowing through the pipe by a certain amount, e.g. from $10^o$ C to $30^o$ C.
The formula is here.
In this video, the speaker says “this pipe is heated by uniform heat generation”. She a... |
When are heating something up on the stove, is there a way it could show heat transfer through radiation?
|
This is my second post on this topic. The first one had some flaws but I resolved them with this new design. This is more of a thought experiment - which I don't think is that outlandish given Einstein had many such thought experiments. The key idea is catching a falling ball via a hook attached to the BOTTOM of the ba... |
When I was studying some graphs I started comparing data with the nuclide chart of https://nds.iaea.org, and I noticed that even for nuclides that aren't typically alpha emitters, even for stable nuclides, is listed the energy released in an alpha decay ($Q_{\alpha}$). How is this possible, or better why is important t... |
I consider the Bell pair $(|00\rangle + |11\rangle)/\sqrt 2$ in the tensor product $H_1 \otimes H_2$
It is a pure state in this vector space and its density matrix is
\begin{pmatrix}
\frac{1}{2} & 0 & 0 & \frac{1}{2} \\
0 & 0 & 0 & 0 \\
0 & 0 & 0 & 0 \\
\frac{1}{2} & 0 & 0 & \frac{1}{2}
\end{pmatrix}
Once the pairs are... |
I am kinda new to physics and this question was bugging me lately. Is it possible in any way to uniquely identify a diamond , maybe through how it refracts light? Do you know if there is any research on the topic? Feel free to just link me potential resources.
Thanks for your answers
|
Both alpha and beta radiations can only travel short distances through air as they're not as penetrating as gamma radiations. How long gamma radiations with 22 MeV energy can travel in air? Is it meters, kilometers, miles, etc.
Is there a difference between a lower energy gamma ray (for example a 2 MeV gamma ray) and a... |
In our introductory solid state lectures we were told that macroscopic electric field that we use in Maxwell equations is averaged out over the atomic distances to smoothen the drastic variations of electric field, like it blows up at nuclear positions.
But clearly, this averaging procedure is dependent over the volume... |
Suppose we have an object, not in orbit, but on a direct collision course with Earth:
This object has kinetic potential energy w.r.t. the Earth. To convert the kinetic energy into chemical potential energy, we could theoretically do regenerative braking with large turbines that charge a battery located on the asteroi... |
Let the quantum system composed by an orthonormal base with the states $|1\rangle, |2\rangle$ and $|3\rangle$ with all being degenereted states of the observable D with eingenvalue $\delta$. So, being the action of the Hamiltonian operator $H$ given by
$$ H|1\rangle = \Omega|1\rangle + \Omega|3\rangle $$
$$ H|2\rangle ... |
Why when we connect two batteries in series but in opposite directions current equals vb1-vb2/r1+r2. I can't understand why we subtract the current of the smaller battery from the greater battery. I know that because they are in opposite directions but why when currents are in opposite directions we subtract thats my q... |
How do we know that the energy density of dark matter in the Universe scales as that of ordinary matter in the expanding Universe? Is it a guess?
|
If a photon approaches a filter with a 0.5 chance of passing through, we have no way of knowing whether it will pass or not. All we know is that if we do the experiment many times, it will pass through 50% of the time.
So, a thought experiment: if we were able to watch a photon pass through the filter, and then if we c... |
I was trying to follow the derivation of an adiabatic theorem in the Appendix F.1 of Jordan, S. P. (2008). Quantum computation beyond the circuit model.
The author claims that, for the sake of this derivation, it's safe to assume the ground state of a time-dependent Hamiltonian always has energy $E_0(t) = 0$. Also, rep... |
If I push a body with f =5N.The body also exerts a force of 5N on me(Action reaction pair).If the resultant is zero , how does the body move at all.
|
For this question, I really have tried to produce some working but the entire thing is just deeply confusing me.
I know my equations for the displacement of this mass will be as follows:
I have successfully derived these equations from the freebody diagram of the mass, and understand where these equations come from. ... |
I have been thinking about why when you want to calculate the gravity force/acceleration that a planet exert on a obect, it is considered that all the planet's mass contributes to create a vertical force downwards.
Only the the mass below the object (those in the planet diameter where the object is locate) generate a f... |
I assume that positive surface tension for the interface between two substance implies that the molecules at the boundary are more "comfortable" - their energy is lower when surrounded by similar atoms/molecules ( giving rise to cohesive force ) rather than when they are surrounded by dissimilar atoms/molecules( giving... |
Hi as a general question, what mechanisms (e.g. impurities) affect σxx but not as much σxy in a semiconductor system at low temperature with impurities.
I know with electric field scattering induced displacement of cyclotron center moves on average parallel to the electric field direction, but does anyone know any othe... |
Imagine a train moving with velocity v wrt a reference frame S, there is a clock in the rear and in the front of the train, and them are synchronized in the train reference, let's call this reference frame S'.
If you, the reference frame S, take a look simultaneously wrt your reference on the clocks, how will the time ... |
Starting from the Einstein field equation (without the cosmological constant),
$$
\underbrace{R_{\mu\nu} - \frac{1}{2}g_{\mu\nu} R}_{G_{\mu\nu}} = \underbrace{\frac{8\pi G}{c^4}}_{\kappa} T_{\mu\nu}
$$
If I'm looking for the vacuum solution, why does it imply that $T_{\mu\nu} = 0$ ?
Then, if I assume that, I get
$$
G_{... |
This is really a beginner question so have mercy, I was listening to a talk in astrophysics and the person said that in order to learn where a bunch of satellite galaxies were in the past "we can use the dynamics of satellites to rewind orbits backwards and trace back how they inform our picture of the local group as w... |
In Uniform circular motion, the force is perpendicular to the direction of velocity so it doesn't change its speed along the tangential direction, but won't it cause an acceleration along the radial direction and increase its speed along the radial direction causing an overall change in its speed.
|
I'm reading the chapter 9 "the path integral for interacting field theory" of the Srednicki's QFT book. The lagrangian we are dealing with here is given by
\begin{gather}
\mathcal{L} = \mathcal{L}_0 + \mathcal{L}_1\\
\mathcal{L}_0 = -\frac 12 \partial^\mu\phi\partial_\mu\phi - \frac 12 m^2\phi^2 \,\,\mbox{(free lagrang... |
In beta decay, a neutron releases an electron and turns into a proton. The inverse happens, though usually not naturally, in positron emission, where a proton emits a positron and becomes a neutron. As the electron has mass, approximately 1/1836th of a proton, I was wondering, for how long this could go on? Could we, i... |
I have found two different ways of doing this and I am seeking commentary on the fine nuance. Suppose there is a Hamiltonian
$$ H=\frac{1}{2}\int\!d^3x \left[ \pi^2+(\nabla\varphi)^{\!2}+m^2\varphi^2 \right] ~~. \tag{1}$$
Hamilton's equations are
$$ \dot\pi=-\dfrac{\delta H}{\delta \varphi} \qquad\text{and}\qquad ... |
My off diagonal terms for this Hamiltonian are the following:
$H = e^{\mp ik_xa}(1+ 2e^{\pm i3k_xa/2}\cos(\sqrt{3}k_ya/2)) $
Next, I want to see the low energy bands, and for this I've been told to expand the Hamiltonian near the corners of the first Brillouin zone. For the two unique corners I got,
$K = \frac{2 \pi}{3... |
A common "cartoon model" of a nucleus is that there are a set of bound energy levels for the protons and a similar set of bound energy levels for the neutrons. The existence of these energy levels helps explain why bound neutrons are stable, even though free neutrons decay. If the decay would require the new proton t... |
Under geostrophic balance, one can write
$$\frac{V^2}{R}+fV-fV_g=0$$ where $V:$wind speed, $V_g:$ geostrophic wind speed, $f:$ Coriolis parameter, and $R:$ radius of curvature.
Solving for $V$, we can get a relationship between $V$ and $V_g$ as
$$V=-\frac{fR}{2}\pm\frac{\sqrt{f^2R^2+4fRV_g}}{2}$$
How does one then dete... |
If so, how do their gravitational fields go through the black hole? Can information be sent this way (via gravitational waves)?
|
I'm an igsce student, I'm taking igsce OL phyiscs.
It's stated in my book that after I draw a graph and the line of best fit, I should get the gradient by choosing two points then form a right angel triangle with them, where the length of the hypotenuse of the triangle should be greater than half of the length of the l... |
Is there a canonical way to describe an open, non-relativistic quantum system with density matrix $\rho(t)$ entirely in terms of the light that it emits and absorbs (and vice versa?) Or is it possible in general for a density matrix trajectory $\rho(t)$ to be induced by several (e.g. possibly contrived and time depende... |
Consider two masses connected by a string over a pulley, like so:
Where mass $M$ is held in place by a hand.
I'm asked to draw free-body diagrams for mass $m$ and $M$ individually, and identify third-law pairs in the two diagrams. I'm then asked to consider when the hand moves and mass $m$ begins accelerating downward... |
I know that the following statement is equilvelent to saying a matrix times its inverse is the identity matrix
$$ \Lambda^\mu_{\rho '}\Lambda^{\rho'}_{\nu}=\delta^\mu_\nu$$
but i would like to show it in subscript notation using the relations:
\begin{equation}
x^{\mu '} = \Lambda^{\mu'}_{\nu}x^\nu
\end{equation}
\begin... |
Let's take a simple $E^3$ space with coordinates $(x,y,z)$ and metric tensor
$$ g = \mathrm{d} x \otimes \mathrm{d} x + \mathrm{d} y \otimes \mathrm{d} y + \mathrm{d} z \otimes \mathrm{d} z $$
The geodesics are straight lines
$\vec{r} = \vec{r}_0 + \vec{v}_0 t$. Let's take a very specific straight line
$$ \begin{aligne... |
Why is $\frac{\partial\mathcal{L}}{\partial(\partial_\nu \bar{\psi})} = 0$, for the Dirac Lagrangian $\mathcal{L} = \bar{\psi}(i \gamma^\mu \partial_\mu - m)\psi$?
This comes up in deriving the Noether current for $\psi \rightarrow e^{i\alpha}\psi$ for example.
My confusion comes from the fact that we can write the fol... |
Let's say we have two completely identical cylinders of some ideal gas (same $P,V,T,n$, etc...), and we just want to double each one's volume.
First Cylinder
The first cylinder undergoes a simple reversible isothermal expansion, from $V_i$ to $2V_i$ (and likewise, $P_i \to P_i/2$). The work done is just $$W = P_i V_i \... |
Any 'physical' quantity is expressed as (generally) a Real Number. Real Numbers are abstract mathematical constructs.
Laws of Physics are written as mathematical equations; where these real numbers are equated to each other (By now we have already left the world of physics and are purely in mathematics)
But when we ... |
In QFT we use, rather than a single Hilbert space, $\mathcal H$, a Fock space$^1$: $$F_v(\mathcal H)=\bigoplus_{n=0}^\infty S_v\mathcal H^{\otimes n}, \tag{1}$$ which allows for states to exist with an arbitrary number of particles. However, having consulted a few different sources I have been repeatedly told that the ... |
I've been wondering: why is the electrical conductivity of a given material defined as the inverse of its electrical resistivity? In other words, why is
$$ \sigma \equiv \frac{1}{\rho}~?$$
It indeed makes sense to define a number called conductivity such that, when the resistivity of the material decreases, the conduct... |
In the action term for Majorana fermion as given in Peskin and Schroeder's question 3.4, the first term is :
$\int d^4x \space\chi^\dagger i \bar{\mathbb{\sigma}} \cdot \partial\chi$
which can be written as
$\int d^4x \space \chi^\dagger i \bar{\mathbb{\sigma}}^\mu \partial_\mu \chi$
where $\bar{\mathbb{\sigma}}^\mu = ... |
I read this paper (the last sentence of Section 3.1). It is stated that in fiber optic interferometric sensors, the interference pattern cannot be detected if visible light is used because most fiber optics are transparent for longer wavelengths. From my understanding, the interference pattern is more apparent when coh... |
If a person (free)falls into a black hole at some point or the other, he will be stretches by a 'force differential' between the two ends of his body. This is the process of spaghettification.
But, general relativity also tells us that any observer who falls into the black hole will be inertial, as he is just moving al... |
We know that gravity changes with height so there must exist a jerk. Could I know the method to find it. Does there exists jounce(4th derivative of position) for Earth's gravity?
|
I need to know the type of camera that is used in a double slit experiment. Both with photons, and that with electrons? Can someone please answer. The type of camera that is used for observation. Is it a normal CCD camera or some other type of camera that captures electrons hitting the screen.
|
I have heard the following statements:
Quarks always exist in a group of 2 or 3, and can not stand alone.
Protons are made up of 2 up quarks, and 1 down quark.
Quantum mechanics allows us to entangle a particle by somehow dividing it into 2 (For example, if a proton's energy is 5 joules, if we split into 2 then sum of... |
My line of thought:
Horizontal: As A moves with 10m/s towards right, B also moves right with same speed. Therefore C also moves with 10m/s towards right. B slides along incline with 5m/s. It has horizontal component of 4m/s. Therefore, net horizontal velocity of block C is 10+4=14m/s.
Vertical: As A moves with 10m/... |
I have got a planar spiral shown in the graph. C1 is the spiral body, and C2, C3 and C4 are the wires to make it a loop, where C2 is under the coil body.
Assume I have known the geometric expressions of C1, C2, C3 and C4 in space.
For a single closed loop $l$, the magnetic flux linkage $\psi$ is equal to the magnetic ... |
Let $A$ denote a bounded operator on a complex separable Hilbert space $\mathscr{H}$. Let $\mathscr{F} = \bigoplus \mathscr{F}_N$ be the Fock space generated by $\mathscr{H}$ where $\mathscr{F}_N$ is the $N$-particle Hilbert space. Let $d\Gamma (A):\mathscr{F}_N \to \mathscr{F}_N$ be defined as
$$d\Gamma (A) =A\otimes ... |
I was reading my class notes and it was written that electrons are more mobile than holes because the effective mass of electrons are lower than that of holes. (μ=eτ/m*)
I checked online to find the relative effective masses of electrons vs holes and in intrinsic semiconductors (like Ge and Si) and found out that the e... |
I’m trying to solve this problem. If you have a rigid insulated tank with $V=10\ {\rm m}^3$ which is initially filled with steam at $p_1=0.7\ {\rm MPa}$ and $T_1=240\ {\rm C}^\circ$. The tank develops a leak and steam slowly escapes until the pressure is $0.15MPa$. I need to then find the final temperature of the water... |
A block of wood rests on a plane inclined to the horizontal at an angle $\theta$. The smallest force acting parallel to the line of the greatest slope which will just move the block down the plane is $F$. If coefficient of friction is $\mu$, then will the weight of the block be $$W = \frac{\mu cos\theta-sin\theta}{F}$$... |
I'm thinking about this through the lens of the $n$-body problem in classical mechanics, which was of course proven to be non-analytic for $n\ge3$ by Poincare. Does this same proof extend to a quantum mechanical $n$-body problem, or is there some way to write the hamiltonian that allows us to find an analytic solution ... |
Just a short mixed quantum state representation question. Given a single qubit density matrix $\rho$, since the Pauli matrices form a basis for 2x2 complex matrices, the Bloch sphere representation can be given as
$$\rho = I + \vec{r} \cdot \vec{\sigma},$$
where $\vec{r} = (r_x,r_y,r_z)$ and $|\vec{r}| \leq 1$.
To gene... |
In my textbook, it's written that work only has magnitude and no direction but it is also in negative so is it a vector quantity or scalar?
|
Given the operators $\boldsymbol{\alpha}$ and $\boldsymbol{C^{(L)}}$ such that
$$
\boldsymbol{\alpha}=\left(\begin{array}{cc}
0 & \boldsymbol{\sigma}_{p} \\
\boldsymbol{\sigma}_{p} & 0
\end{array}\right) \quad
$$
where $\sigma^{1}$ are the Pauli matrices
$$
{\sigma}_{x}=\left(\begin{array}{cc}
0 & 1 \\
1 & 0
\end{arra... |
I have a cylindrical permanent magnet with uniform magnetization $\mathbf{M}=\mathbf{a_z}M$, length $L$ and Diameter $D$.
I also have the following expressions for the magnetic flux density and magnetic field intensity inside the magnet.
$$\mathbf{B}(z)= \frac{\mu_0M}{2} \Bigg[ \frac{z+ \frac{L}{2}}{\sqrt{\big(z+\frac... |
I've been studying the work-energy theorem and also how the kinetic energy formula is derived from the equations of motion. It seems like the work-energy theorem is another way to rewrite the motion equations that, this time, are being supported by the second Newton's law to involve forces.
Does knowing the motion equa... |
I am trying to reproduce the Born-Infeld term for the $D$-brane action as explained in Szabo's BUSSTEP Lectures and must admit I am utterly confused by some of the steps.
This is a long and technical question, so I first give some context, then I give my problems.
All of this can be answered easily if someone can point... |
I am currently studying Short Course On Topological Insulator by J. K. Asb´oth, L. Oroszl´any, A. P´alyi.
In Chapter 3.2, I have a few questions to ask regarding it:
Is the phase $e^{i\phi}$ in (3.31) arbitrarily introduced?
I do not understand why $p_{0}$ and $p_\pi$ in (3.33) can take the values of -1 if they foll... |
If we assume that principle of quantum superposition would be actually not true, would this invalidate conclusion from the Alain Aspect experiment that there is no local hidden variable?
|
Am I correct in understanding that in Loop Quantum Gravity, loops are somehow interconnected with each other or interact, or is there some form of quantum entanglement between them? And if so, can we assume that there was no connection between loops before the appearance of space-time?
|
Consider the process of condensation of vapor on falling subcooled droplet in the stagnant saturated vapor (neglect the vapor drag on droplet). What can be said about the relation between the droplet diameter and the time for reaching saturation temperature for droplet?
I wanted to build a mathematical model to calcaul... |
Recently I got a problem that equated the time derivative of a cross product d/dt (P x Q) with a function of time (like t + t^2).
Ex. d/dt (P x Q) = 5t - 6t^2
My question is, how can you have an equation with a cross product derivative (which is itself a vector) with a function of time?
|
In elementary physics, I have learned mass as the amount of matter (naively) and energy as the ability to do work. Now we know that they interchangeable by famous Einstein's equation:
$$E=mc^2$$
It seems from here that they are interchangeable, but then I watched this video, which says, in a nutshell, that the mass act... |
In Quantum Mechanics, the quantum state of the physical system lives in an infinite-dimensional Hilbert space and can be written in terms of two different bases, the position basis (uncountably infinite) and the energy basis (countably infinite). Apparently, the two bases are of different cardinalities, which violates ... |
Faraday's law states that
the circulation of the electric field E around a closed loop is equal to the rate of change of the magnetic flux through the area enclosed by the loop
In integral form:
$$\varepsilon =\oint \vec E \cdot d \vec l = - \frac{d\phi}{dt}$$
$\varepsilon$ is defined as the electromotive force, that... |
If in an electrically neutral body there are equal number of electrons and protons, then why not due to repulsions between the electrons - electrons and proton - proton the body does not tear apart into pairs of electrons and protons.
|
We know that in normal coin-toss there is two probable states HEAD OR TAIL. When we commence for measuring only get head or tail,is it means two probable states collapse into one {H or T}.in mathematical language we have called it mutually exclusive(not simultaneous) but but but in QM simultaneously two states possible... |
Suppose two elétrons separated by a distance that their mutual interaction is so weak that can be regarded as null.
Suppose also they are under the effect of a constant and uniform electrical field and moving inside it in the same direction.
Is there acceleration in relation each other?
Do they feel the force of the ... |
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