Superposition Definition and 673 Threads

How to teleport Schrödinger’s cat: this video presents the full quantum teleportation procedure, in which an arbitrary qubit (spin, etc) is teleported from Alice to Bob by way of a pair of particles entangled in a bell (EPR) state and the transmission of information via a classical channel.

I've been studying quantum mechanics, and working problems to get a feel for expectation values and what causes them to be real. I was working the problem of finite 1D wells, when I came across a situation I did not understand. A stationary state solution is made up of a forward and reverse...

I’m understanding that QM superposition in which, for example, a single electron acts as a wave in a double slit experiment and interferes with itself by passing through both slits simultaneously (when there are no detecting devices priorly measuring either slit) presents a result which is...

Is it possible to measure an electron, and, say, get multiple simultaneous results about it's motion, as you didn't break superposition? (E.g. you could simultaneously read 5mph, 10 mph and 15mph), and could this be used for quantum computers, to store store and gain huge amount of information...

Hi. As far as I know, superpositions of waves are normally considered to be waves too, even in dispersive media. But how can they still be solutions of a wave equation of the form $$\left(\frac{1}{c^2}\frac{\partial^2}{\partial t^2}-\Delta\right)u=0$$ if ##c## isn't the same for all of them...

Suppose I could restrict an electron to a very small space byfor example using multiple magnetic fields, then could I not be sure with 100% probability that the electron was there before and after a measurement? Wouldn’t such a experimental set up dis prove the idea that the electron had freedom...

Homework Statement Suppose light is prepared in a coherent superposition of linear horizontal polarization and linear vertical polarization. What is the resulting polarization according to Jones calculus if it passes through: a linear polarizer at a 45-degree angle (0 degrees would be...

Hi, I know that entanglement is real and that it tells us something profound about the nature of quantum objects like electrons and photons. I can't explain to a family member how we know that two twin photons in the EPR experiment started off in a superposition. In other words, how do we know...

<Moderator's note: Approved. The original thread has been this. The relocation in QM is better suited in case the thread turns into a direction where physical questions are the subject rather than quotations.> I have heard many astounding things about QM. For example, that particles have no...

Hello My friend claims that the theory of electron superposition has been overturned recently. That this was due to measurement errors, and that electrons fly like orbs and planets in orbits, but I can not find any sources. I am asking for an answer, thank you very much. (I'm sorry, I have no...

In the wikipedia page and on every book they proof the transformation by equaling the the equivalent resistance between any pair of terminals while disconnecting the other node.https://en.wikipedia.org/wiki/Y-%CE%94_transform Why this should make the two circuits equal? How can we apply...

Assuming Quantum mechanics is a probability theory that describes something real (which should be our first presumption), is there ever only a superposition of 2 states? The reason I ask this is because: For calculating the probability of an outcome you square the sum of the probability...

do you eliminate an independent current/voltage source one at a time or can you do all of them at once. Let us say you have 5 independent voltage sources and 5 independent current sources. Do you short circuit 5 of those voltage sources and leave 5 independent current sources or do you have to...

Homework Statement I wish to solve this integral $$b_{lm}(k) = \frac{1}{2(\hbar)^{9/4}(2\pi)^{5/2}\sqrt{\sigma_{px} \sigma_{py} \sigma_{pz}}} \int_{\theta_k = 0}^{\pi}\int_{\varphi_k = 0}^{2\pi} i^l \text{exp}\left[ - \frac{1}{(2\hbar)^2}\left(\frac{(k_z - k_{z0})^2}{\sigma_{pz}^2} + \frac{(k_y...

I'm having trouble with trying to find the expansion coefficients of a superposition of a Gaussian wave packet. First I'm decomposing a Gaussian wave packet $$\psi(\textbf{r},0) = \frac{1}{(2\pi)^{3/4}\sigma^{3/2}}\text{exp}\left[ -\frac{(\textbf{r} - \textbf{r}_0)^2}{4\sigma^2} + i\textbf{k}_0...

1. Homework Statement . Figure 1 shows a 50 Ω load being fed from two voltage sources via their associated reactances. Determine the current i flowing in the load by: (a) Thevenin's theorem (b) Superposition (c) Transforming the two voltage sources and their associated reactances into current...

We have a 1 dimensional infinite well (from x=0 to x=L) and the time dependent solution to the wavefunction is the product of the energy eigenstate multiplied by the complex exponential: \Psi_n(x, t) = \sqrt{\frac{2}{L}} \sin(\frac{n\pi x}{L}) e^{-\frac{iE_n}{\hbar}} Now, I want to create a...

Homework Statement Suppose there is a tank filled with water and a piston of area S exerts a force F on the water. Suppose I divide the water boundary touching the piston to - N small equal " square " molecules. Then , the force on the upper face of each molecule is F/N . Also, the area of...

I'm watching a lecture on the intro to quantum computing. See the attached image which will be useful as I describe my question. So the professor says that we have this single photon and it's in this state, ## | 0 > ##. He states that when we send this photon through a beam splitter that it...

Can someone explain the meaning of the k vector and the general meaning of this equation?

Homework Statement 1. Homework Statement [/B] The displacement y of standing wave that is obtained by a superposition of waves : Y1 = 3 sin (2##\pi##(0.5t - 0 25 x)) Y2 = 3 sin (2##\pi##(0.5t + 0 25 x))Homework Equations Formula for standing waves Y = 2Asinkx coswt The Attempt at a Solution Y1...

If we consider the Unitary evolution of the wavefunction, and interpret measurements as becoming in superposition, taking it that the measurement device gets in a superposition of spin up and spin down, do two measurement devices that each measure one particle of an entangled pair become...

Homework Statement In the circuit of the figure, determine the intensities I1, I2, I3, I4, I5 and the voltage Ug. Homework Equations Superposition and Kirchoff The Attempt at a Solution 20-10I1+5I3-10I1=0 5I3+Ug+5I5=0 20I2+10I2-150=0 From the last equation, 30I2 = 150, I2 = 5 A KNOTS...

There are two polarization filters, A and B. Polarization filter A has angle of 0° and B has an angle of 30°. A photon is in superposition, so it doesn't have a definite polarization axis. The likelihood it's passing through a filter is depend on the difference between angle of the...

Suppose a neutral meson decays into an electron and a positron. Are the two particles entangled as they fly apart? Before any measurement takes place, are the particles in a mixed superposition as to which one is the electron, and which one is the positron? Is there a way to test for such...

A very simple question: if given a vector ##v(t_0)## and two group functions ##G(t)## and ##G'(t)##, here ##t## is the parameter of time, the two group functions act on ##v(t_0)## simultaneously, then we can get a vector field ##v(t)##, then how to get ##v(t)##?

I recently found this article about the dynamics of the wave function. It has some good simple illustrations and I found it valuable. But the author has a question himself, about understanding the Schrodinger equation. I wonder if anybody here could fill in the missing piece. The relevant part...

Homework Statement In a photoelectric effect experiment, a monochromatic plane wave of light falls on a metal plate. The electric field in the light wave at a point near the plate varies according to E=E_0 \cos (\omega t). This results in a saturation current of 6 μA. If instead, the light wave...

The energy and momentum of a closed system is always conserved. If a laser can emit perfectly parallel and perfectly superimposed light waves (occupy the exact same space) that are perfectly 180° out of phase and of the same frequency, what can be said about the energy and momentum of the...

1. Homework Statement Two speakers S1 and S2 derived by the same amplifier and placed at y=1 and y = - 1.The speakers vibrate in phase at 600 Hz. A man stands on the x-axis at a very large distance from the origin and starts moving parallel to the Y - axis. The speed of sound in air is 330ms-1...

Homework Statement Verify Superposition Principle using Matlab, given a DC source of 100V, an AC source of 50V, 60Hz and three resistances, R1=10 ohms, R2=20 ohms and R3=15 ohms. I created the circuit below and ran the program. Result: Homework Equations None, just running the program...

Homework Statement A bound particle is in a superposition state: \psi(x)=a[\varphi_1(x)e^{-i\omega_1t}+\varphi_2(x)e^{-i\omega_2t}] Calculate <x> and show that the position oscillates. Homework Equations <x>=\int_{-\infty}^{\infty} \psi(x) x \psi^*(x) \mathrm{d}x The Attempt at a...

I am sorry to bore you people with a very, very simple question (there is no catch unless QM throws it :nb) ): ?:) If we have a half silvered mirror and we fire a single photon at it at an angle of 45°, it either passes or reflects from the mirror. To be more precise, the photon becomes in a...

Is Superposition of the position of particle limited to a certain area or is it unlimited? Like, an electron: Can an electron on Earth be like in Jupiter or proxima centauri due to superposition? I mean, such vast distances?

If a single point charge is moving, then the component of the electric field normal to the motion is larger (by the gamma factor) than if the charge were stationary. Now consider an infinite line of charges (with a small separation, the same between each charge). If the whole line is moving...

Can anyone please describe to me how superposition in quantum mechanics works, preferably using real life places and objects as examples? I am having trouble understanding the concept.

Hi. My question is a general one but I will use an infinite well as an example. Without knowing details of the exact wavefunction I presume it can exist as a linear superposition of an infinite number of energy eigenstates ? Without knowing the exact wavefunction ; does that mean that when the...

Homework Statement I have tried to answer the superposition question in the included file. I have gone through the workings as the same as in my john bird electrical book. I believe I have done nothing wrong in my approach and should be getting the same answer as my thevenins answer. the...

Hi. I just want to check that I understand the following. If I have a general superposition of wavefunctions satisfying the TDSE then that superposition also satisfies the TDSE. But that superposition only satisfies the TISE if the energies are degenerate because the TISE is an eigenvalue...

When a spring is fixed at both ends and it is vibrating back and forth, reflection will occur. So where are the nodes and antinodes? Are they at compression or rarefaction region?

Homework Statement I am supposed to find probability of staying in x < 0 for a superposition of two Gaussians. The wavefunction is something along the lines of: Homework EquationsThe Attempt at a Solution Usually, the step involved in finding probabilities for 1 particle is just to perform...

Homework Statement The equations for two waves traveling along the same string are $$f_1(x,t)=a\sin(bx-qt)$$ and $$f_2(x,t)=a\sin(bx+qt+\frac{1}{3}\pi),$$ with $$a=3.00\times 10^{-2},b=4\pi m^{-1},$$ and $$q=500s^{-1}$$. (a) Calculate the amplitude and wavelength of the resultant displacement...

Can the kind members of this forum please help me make the logical leap from an entangled pair of electrons or photons to that of the pair being in a superposition where the observation of one effects the state of the other? For example, my understanding is that, through the conservation of...

When two quantum objects interact, when does this interaction destroy their superposition and when does this interaction causes them to be entangled and allow the superposition to remain.

Hi all, is my description below a reasonable attempt in explaining how a standing wave forms? The main part I am a bit confused as to how to explain is why the antinodes move up and down. Thanks!A standing wave is formed when energy of a wave of the right frequency is trapped in the system...

Homework Statement Homework Equations ##f_beat=f_1-f_2## The Attempt at a Solution Why are the two different answers? Is it because the first question is asking for how often it fluctuates, and the other is actually asking for the frequency of the sound? Why is the resultant tone the...

If I had a box with a bunch of particles in superpositions in it, what would I find if I found the mass of the box? First: Is it possible to have have box like this? If not what about theoretically. Second: Does weighing the box collapse the superposition of the particles? Third: Could I, by...

Homework Statement Homework Equations current/voltage division V=IR Kirchoffs Laws The Attempt at a Solution and adding all Vx I get 9.818181V.[/B]

Upon reading Landau QM, the Principle of superposition of states, I got confused. It states (and i quote): "Suppose that, in a state with wave function Ψ1(q), some measurement leads with certainty to a definite result 1, while in a state with Ψ2(q) it leads to a different result 2. Then it is...

I do not really understand why we don't include 7Ω resistor in step 1, and I need some explanation with step 2.