Questions tagged [superposition]
A basic principle of solutions of *linear* differential (often wave) equations, ensuring that the sum ("superposition") of two solutions is automatically a solution as well. Conversely, solutions (amounting to quantum states in quantum mechanics, since the Schrödinger equation is linear) can be represented as a sum of two or more other distinct solutions, and so can be Fourier/eigenstate resolved to enhance mathematical tractability.
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Finding the voltage across $R_3$ [closed]
I have the following circuit. $V_B = 18V, R_1=3k\Omega, R_2 = 6k\Omega, R_3 = 10k\Omega, R_4 = 1k\Omega \text{ and } I_A=1,2mA$.
What's the value of $V_4$ here?
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Superposition of waves and interference
For mechanical waves, Is the principle of superposition valid for waves that do not travel in the same plane ? For eg with one wave S1, travels along positive x-direction and another wave S2, is ...
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Intensity In Superposition Of Waves
I'm not able to quite understand this:
Consider a superposition of 2 opposite mechanical waves: when they interfere destructively, we say that the particles in the region of superposition have 0 ...
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Schrödinger evolution after a position measurement, without collapse
Consider the following physical situation. Two position detectors are located next to each other, each one carries only YES/NO information on whether the particle hit that detector. A particle, let's ...
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Gluons and their States
I've learned that gluons, which mediate strong interactions among quarks, always exist in a superposition of two or more color charges. To my knowledge, any superposition of eigenstates of an ...
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Time dependent superposition [closed]
In the case of a particle in a infinite square well.
The wavefunction is given by: $\sqrt{\frac{2}{L}} \sin{(\frac{n\pi}{L}x)}$
The probability is given by $ |\psi(x)|^2 $
Here the maximum value for ...
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Don't seem to understand the behaviour standing waves
I have many confusions regarding standing waves. Firstly, will the frequency of standing waves be the same as the emitted waves that make up the standing wave?
What about wavelength? Will wavelength ...
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Confused regarding the wavelength of standing waves and their relation with wave speed
Suppose we have an air column closed at one end and open at one end. We know, the general formula for the wavelength of the stationary waves of different harmonics will be equal to $4L/n$. My ...
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How does dual nature of matter affect collision at the quantum level?
I have a question suppose having two fundamental particles collide which each other at the quantum scale , then what will the collision behave as
Will the particle nature be dominant and make sure to ...
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The evolution of observables in the Heisenberg picture
Suppose that a system $S$ undergoes the following time-evolution:
$t_{1} \rightarrow t_{2}: |x_{a}\rangle \rightarrow \sum c_{i}|x_{i}\rangle$,
where $|x_{a}\rangle$ and each of $|x_{i}\rangle$ is a ...
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Is there any way to check superposition in a source of photons?
Suppose we are given a box containing 10 photons. We only know that the box contains:
5 horizontally and 5 vertically polarized photons
or
5 left-circular and 5 right-circular polarized photons.
...
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On the field leakage problem in quantum experiments
In a quantum experiment, does the leakage of the electromagnetic fields lead to the suppression of quantum effects? For example if I have an electron in a box, in some quantum superposition. Can I use ...
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Visualizing 3D Lissajous curves
Lissajous figures are generally 2 dimensional, i.e. X and Y. But if an oscillation along a third axis Z (normal on the XY plane) is introduced, how would the resulting path look like? is there any ...
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Schrodinger's black hole [closed]
Is it possible to have an object that is a quantum superposition of a black hole and an equivalent mass that is not a black hole?
Suppose we are adding iron atoms one at a time to a pile somewhere out ...
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Erratum in Schlosshauer's "Decoherence" textbook (on the outcome of a SG experiment)?
In his textbook on Decoherence, Schlosshauer is trying to explicate the difference between a superposition and a classical ensemble. Considering a two-level system and using fairly standard notation, ...
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What is the physical meaning of acting an operator on an arbitrary quantum state? [duplicate]
Let |+> and |-> are the two eigenstates of Pauli-X.
If an incoming arbitrary state is |psi> = c1|+> + c2|-> and we act on this with pauli-X,
then the outcoming state is a different ...
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Question regarding beats
If two waves of different frequencies, say $x_1=A\sin(\omega_1t)$ and $x_2=A\sin(\omega_2t)$, are moving along in the same direction and these waves satisfy the condition $$|\omega_1-\omega_2|\ll \...
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Schrödinger's cat possible resolution
The premise behind Schrödinger's cat as I understand it is there is a radioisotope whose quantum randomness is tied to the alive or dead status of a cat in a box. The idea is that the cat is both dead ...
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How to calculate the energy of a particle in superposition? [duplicate]
lets say we have particle bc particle bc has a 50/50 odds of either turning into particle b or c
each has energy of 2 units. particle A takes the energy from either b or c depending on the result ...
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What is the beat frequency if two strings with differing tension?
In certain ranges of a piano keyboard, more
than one string is tuned to the same note to
provide greater intensity. For example, the
note at 147 Hz has two strings at this pitch.
If one string slips ...
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Fermion location and superposition
That a fermion's wave function can extend over space is a perfectly reasonable concept, but why do some physicists also say that the $ \textbf {point particle itself} $ can exist in multiple locations ...
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Why would there be a larger data dispersion at minimums than at maximums in a graph of intensity against path difference?
I'm doing a rather simple experiment concerning the superposition of two waves and the impact that path difference of 2 identical waves has on recorded intensity at that point. However, there is ...
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What does Huygens' principle really say?
Until recently, I thought of Huygens' principle in the following way:
Define a wave front as a continuous line in space along which a given wave has equal phase at any given point in time. For ...
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Interpreting a Density Matrix Resulting from Decoherence of a GHZ State
This questions extends on this question and on the given answer.
What this question is about:
Decoherence model. Consider a simple decoherence process modelled by $$\mathcal{E}\left(\rho\right)=p_0\...
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Superposition of charge states in the Neutral Pion
The quarks of neutral pions don't exist in a pure flavour state, and instead are described as a superposition of up-antiup with down-antidown:
$\frac{u\bar{u}-d\bar{d}}{\sqrt{2}}$
However up and down ...
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How much does the collapse of the wave function reveal about the state of the quantum prior to collapse?
The best way I can pose this question is through an example: suppose a photon passes through a beamsplitter, putting the photon into a superposition of the two paths (reflected or passed through), and ...
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How to apply Schrödinger equation to superposition with time dependent factors?
The question comes from reading through either of these two papers:
https://doi.org/10.1103/PhysRevB.35.3629
https://arxiv.org/abs/1811.05886
The question is on the time dependence of a state like:
$$|...
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What is the term for the number of wavelengths in a wave packet?
If I have several wave packets, such that they consist of 1, 2, 3, etc. wavelengths of a single wave with a set frequency/amplitude what do the wave packets vary by?
Ie. what is the generic term for ...
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Standing waves in a spring [closed]
So the question goes like this
A string 1 m long is fixed at one end. The other end is moved up and down with frequency 15Hz. Due to this , a stationary wave with four complete loops , gets produced ...
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In slit experiment: is it one wave function before and two wave functions after the split?
Forgive my round-about background to the question: I'm curious how the experiment "fires electrons slowly that interact with themselves"... I'm thinking that's just a simplification?
I feel ...
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Is a PBS a measuring device without observer?
Let a photon In superposition of v and h polarization is going through a Polarizing beam splitter PBS. If it passes, it is in h polarization on path A, otherwise is in v on path B. Let have a detector ...
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How to induce superposition from a collapsed quantum state?
It is easy to collapse a superposition by measuring it.
But how to induce a new superposition from a previously collapsed spin or polarization?
Electron A is deflected up by an inhomogeneous magnetic ...
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How is the initial condition term $\frac{1}{\sqrt{2\pi}}\phi(k)$ derived for free particles?
I'm reading Griffiths' introduction to quantum mechanics. It is explained that solutions to the Schrodinger equation are expressed as linear combinations of separable solutions $\{\psi_n(x)\}$.
$$\Psi(...
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Confusion with quantum superposition
I have been studying QM and I think doing research on quantum superposition got me more confused about the topic. So I have two interpretation that I came across:
A quantum state that is in ...
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Confusion about superposition of bound and scattering states in QM
My understanding is that bound states are solutions to the Schrodinger equation where $\lim_{x\to\pm\infty} V(x)=0$ and $\min V(x)\leq E \leq 0$, in which case there are discrete allowed energies. In ...
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Question on notation of eigenvectors of position operator in quantum mechanics
From the first postulate of quantum mechanics we known that the vector $|\psi\rangle$ is the mathematical entity that says, intuitively, "in a time $t$, the (state of a) system is a vector".
...
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ODE solutions for a driven oscillator in higher resonance modes
An ODE for a driven, undamped, oscillator might be written as
$$
m\frac{d^2y}{dt^2}+ky=\sin{(\sqrt{k/m})}t
$$
If the initial conditions are $y(0)=0$ and $y'(0)=0$ and the values of parameters are $m=1$...
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Feynman diagrams and path integral
In a Feynman diagram, can we consider that the propagator specifying the transition amplitude of a particle (let's say, of a "real" electron, or of a "virtual" photon) between two ...
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Does a non-stationary quantum particle in a potential well approach a stationary solution of the Schrödinger Equation?
I have come across this video on Youtube where someone simulated the wave function of a moving particle in an unspecified harmonic potential well. (Link: https://www.youtube.com/watch?v=hHAxLE181sk , ...
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Why does quantum superposition not cancel out the whole universe?
Sorry if this is a stupid question. My layman's understanding is that quantum mechanics describes the universe as a wave function, which can be understood as a weighted superposition (linear ...
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Is all information of the quantum numbers $m\ell$ lost in a superposition?
I have learned that to create real spherical harmonics, a superposition of degenerate spherical harmonic eigenfunctions can be created using ±ml. For example, the px and py (l = 1) spherical harmonics ...
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Is it correct to say that all nonstationary states in a superposition of nondegenerate eigenfunctions of the Hamiltonian? [closed]
Stationary states no not evolve with time, whereas nonstationary states do the opposite.
I have essentially a two small questions (assume a time-independent Hamiltonian):
Is it true to say that a ...
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Is "high impedance" state analogy with "superposition" state? [closed]
In digital logic (classical bit), there's a state called "1" which is a defined high voltage, for example 2.7 V - 5.0 V. To achieve it we must connect it to VCC.
And "0" which is a ...
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A question on Faraday's law of electromagnetic induction
Faraday's law states that $$\varepsilon=-\frac{d{\phi}}{dt}$$ where $\phi$ is the magnetic flux and $\varepsilon$ is the induced emf.
If the object is symmetric, it's easy to determine across which ...
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Why, in low energy situations like atomic physics, are massive particles found to be in integer number states?
In quantum field theory electrons are conceptualized as quantized excitations of the quantum electron field. Generically the electron field can be in a superposition of number states. This is related ...
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Does a waveform of frequency $f+\Delta f$ beat against a wave of frequency $2f$?
In the elementary treatment of waves, beating occurs between two waves of similar frequencies because
$$\cos(2\pi f_1 t)+\cos(2\pi f_2 t) = 2\cos(2\pi \frac{f_1+f_2}{2}t)\cos(2\pi \frac{f_1-f_2}{2}t)$$...
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Phase of the standing wave constituents
Do 2 superimposed waves have to be 180/0 degree apart to form a standing wave? It seems to be the necessity for forming nodes of 0 displacement (taken that their amplitudes are the same) but can they ...
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How do different $|\text{Alive}\rangle+|\text{Dead}\rangle$ kind of states behave under decoherence?
I am looking for literature that investigates said behaviour for spins. So far I found many papers on how to measure the macroscopicity of states and therefore a classification of macroscopic states. ...
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What is the effect of changing the volume of a permanent magnet in the vicinity of an electromagnet?
If I have a single Neodimium permanent magnet, held at a fixed distance (gap distance) from the end of an energised coil, what would be the effect of adding a second magnet to the back side of the ...
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How to correlate the frequency of source to The frequency of particle just between the two medium while transmission and reflection of wave?
When a pulse travels through rarer to denser medium,two new waves (reflected and transmitted) are formed from incident wave,While the wavelength of the Transmitted wave differs from wavelength of ...
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