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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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1answer
84 views

Double slit experiment- light intensity

The standard explanation for the interference pattern is one of constructive and destructive interference between the light waves from the two slits. But, am I right in thinking that light intensity ...
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2answers
118 views

Interference of Schrödinger's Cat states?

A "Schrödinger's cat state" is a macroscopic superposition state. Quantum states can interfere in simple experiments (such as the Mach-Zehnder/Hong-Ou Mandel/etc). Can Schrödinger's cat states be made ...
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1answer
137 views

Does the non-linear Schrodinger equation satisfy quantum mechanics rules?

Thinking about the 0+1 dimensional (time-only) non-linear Schrodinger equation: $$i\frac{\partial}{\partial t} \psi(t) =\kappa |\psi(t)|^2 \psi(t).$$ Treating $\psi$ as a wave function instead of a ...
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1answer
266 views

Constructive interference derivation

What is the difference between using $y=A\sin\omega t$ and $y=A\sin(ct-x)$ in a wave formula? I am not a math student and I am not getting this.
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1answer
172 views

The superposition principle for linear waves

As far as i've seen, the proof for that principle is to show that, the equation representing linear waves has the perk of being linear, thus if y(x,t) and z(x,t) are solutions of the linear equation,...
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2answers
173 views

Principle of interference between two waves of same wavelength

We have two waves with the same wavelength that have a path difference. Why does the path length difference have to be an integer multiple of the wavelength in order to obtain constructive ...
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2answers
73 views

How can you know an unmeasured quantum particle is in several states at once?

If a quantum particle/system has not been measured/observed yet, how can you know it is in several places/states at the same time?
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1answer
59 views

Does it make sense to ask: what is the probability of a particle being found in a certain state at time $t>0$?

I am dealing with a problem which involves a quantum system of orthonormal two states, $\left|\nu_1\right>$ and $\left|\nu_2\right>$, which are eigenstates of a time-independent Hamiltonian, ...
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1answer
83 views

Statevector formalism,$|\psi\rangle =c_1|A\rangle +c_2|B\rangle \neq (c_1a_1+c_2b_1)|u_1\rangle +(c_1a_2+c_2b_2)|u_2\rangle $

In statevector formalism suppose two particle $|\psi\rangle =c_1|A\rangle +c_2|B\rangle $ where $|A\rangle =a_1|u_1\rangle +a_2|u_2\rangle , |B\rangle =b_1|u_1\rangle +b_2|u_1\rangle $, but $|\psi\...
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1answer
61 views

How is mass accounted for when a particle is in a superposition? [duplicate]

When dealing with a particle as represented by a probability field, how is mass distributed across the field? Would the mass be averaged across the field?
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4answers
2k views

Schrödinger's cat bra-ket interpretation [closed]

Let $\vert\text{#}\rangle$ be the vector state of the cat, $\vert1\rangle$ the "alive" state, and $\vert0\rangle$ the "dead" state. Using the normalization condition $\langle \text{#}\vert\text{#}\...
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1answer
104 views

Can two semi-infinite plane waves undergo perfectly constructive interference?

This is building off of a question I asked here. When discussing the linked problem with some friends, the consensus seemed to be that the reason two identical semi-infinite plane waves cannot ...
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2answers
72 views

Three slits experiments [closed]

What is the results of three slits experiments ? What is the difference between it and 2 slits experiments?? How can measure superposition by three slits experiments
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6answers
3k views

If I was Schrödinger's cat, what would I feel? [closed]

What I'm doing Note before reading: I've made two edits for clarification The first starts at: "To clarify based on answers, I think ya'll are missing the meat of the question:" The second starts ...
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3answers
150 views

Time evolution of eigenstates superposition

If a system is in a state $\psi$ which is superposition of, let's say two, energy eigenfunction, namely $\psi_1$ and $\psi_2$, so that $$\psi(t)=\psi_1e^{-i\omega_1t}+\psi_2e^{-i\omega_2t}$$ (I am ...
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0answers
29 views

Polarization of light using QM principles [duplicate]

If we have vertical linearly polarized light and if we put it through a polarizing filter oriented at 45 to the vertical, then only half of the light passes through. I am able to intuitively grasp ...
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0answers
45 views

Can light of different frequencies interfere with each other?

In principle I'm aware of superposition and how it works. Nevertheless I'm not really able to answer the following: Will two light beams of different frequencies interfere with each other? More ...
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1answer
105 views

Would Schroedinger's cat smell 50% like death? [duplicate]

If we left Schroedinger's cat in a superposition for a week would it begin to start smelling 50% like a dead cat and 50% like a living cat? Would the smell of death immediately disappear if we opened ...
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1answer
119 views

Quantum superposition in density matrix formalism

I was thinking about quantum superposition and stumbled into something that made me quite uncomfortable. Consider a qubit with Hamiltonian eigenstates $|0\rangle$ and $|1\rangle$. To each of these ...
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1answer
161 views

Superposition principle in electrostatics

Poisson's equation in electrostatic does not satisfy the linear superposition principle. Can I say that since Laplacian operator is a non-linear operator so it does not follow the linear superposition ...
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3answers
191 views

What happens in an organ pipe at frequencies other than the harmonics?

I learned that, at frequencies corresponding to harmonics, standing waves are formed. But what actually happens at other frequencies? Won't the reflected wave superimpose with the original wave? Do ...
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1answer
77 views

Destructive Interference of two wave pulses [duplicate]

Suppose two identical transverse wave pulses are travelling towards each other on a string where one is inverted with respect to the other. When they meet, destructive interference will occur and the ...
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1answer
101 views

On Superposition In Diffraction

I am a high school student learning Physics. I am currently learning about diffraction of waves, be it water waves, light waves each, in systems where there are 2 slits for it to diffract through. I ...
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2answers
172 views

Solution of Schrodinger equation

I am reading 'Particle in 1 dimensional box' and 'Potential step' in Quantum Mechanics. In the figure shown we have two same looking schrodinger equations, equation 1 and equation 2. Why solutions of ...
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1answer
214 views

Linear combination of wavefunction

What does plus or minus sign indicate in linear combination of wave functions?
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3answers
267 views

How to interpret a wavepacket in quantum field theory: is it one particle or a superposition of many?

In 'classical' quantum mechanics, a wave packet is a (more or less) localized particle. The wave packet can be expanded in a superposition of plane waves, each with a defined momentum and energy. This ...
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5answers
132 views

Which-way experiment with electrons

Consider the double-slit experiment done with a stream of electrons, sent individually toward the double-slit screen and detection plate. A moving electron is a moving electric charge, which by ...
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2answers
99 views

De Broglie Wavelength interpretation

I've just started learning about the double slit experiment (just in the short appendix section in Schroeder's Thermal Physics), and I'm extremely confused by this one thing: In it, out of basically ...
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0answers
67 views

Finding the expansion coefficients of the decomposition of a 3D Gaussian wavepacket in the eigenfunctions of the Hydrogen atom

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/...
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1answer
139 views

Superposition of Magnetic fields in a Transformer

Lets say we have a transformer with two primary coils. The coils are positioned end to end such that unlike poles are adjacent (NS or SN). The current in one of the coils has a phase shift of 90 ...
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2answers
381 views

Sound beats mathematical expression

I am reading about sound beats. According to the superposition principle, if at a certain position the two waves are given by, let say, $$\ y_a(t)=Asin(2\pi f_at)$$ $$\ y_b(t)=-Asin(2\pi f_bt)$$ ...
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0answers
198 views

How to best describe wave behavior on even dimensions?

Main source: http://www.mathpages.com/home/kmath242/kmath242.htm On this article, as far as I understand, the author claims that wave behavior on even dimensions would give rise to many waves with ...
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1answer
212 views

Mach-Zehnder interferometer reaction to input light with polarization state ±45˚?

We have a Mach-Zehnder interferometer with two non-polarizing beam splitters. The polarisation state of the input beam is a superposition of +45˚ and -45˚ polarizations. In the upper arm of the ...
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3answers
135 views

Can any type of wave produce an interference pattern from two sources?

Can any type of wave produce an interference pattern similar to the one in a double slit experiment? So for example, could a radio wave create an interference pattern through the airwaves?
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2answers
170 views

Full solution of the wavefunction for the particle in a box problem

The particle in a box problem is a common question that people are taught in order to get some practice using Schrödinger’s equation. For this kind of problem one usually solves the equation for ...
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1answer
33 views

Quantum Computing, and if a Q-bit can be entangled and in superposition at the same time

I was wondering if a Q-bits can be in both entangled and in superposition at the same time?
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2answers
500 views

Assumption in the derivation of Schrödinger's equation

I read on the "derivation" (with some assumptions) of the Schrödinger equation. The idea is to start from $$T + U = E $$ wher $T$ is kinetic energy, $U$ is potential energy, and $E$ is total energy. ...
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1answer
144 views

How to conduct the electron double slit experiment

I am planning to conduct the electron double slit experiment for a project in my school. Even after researching quite a bit online, I wasn't able to find a proper guide that explains the materials and ...
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1answer
160 views

Can a superposition of a travelling wave and a standing wave give a standing wave?

I have two similar questions: 1) I have heard, that a travelling wave can be understood as a superposition of standing waves. Can you exaplain this (some images would be wonderful)? 2) Can a ...
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1answer
82 views

Never ending quantum superposition? [closed]

So I am wondering over the Copenhagen Interpretation how can a decoherence or measurement ever happen. If in the beginning of the universe everything was in a state of coherence being in ...
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0answers
47 views

Supposing that a quantum system is in a degenerate ground-state, is it valid to call this a “superposition” of the possible groundstates?

According to the adiabatic theorem, a quantum system can be prepared in the ground-state of some Hamiltonian $H_f$ if it starts in the ground state of some Hamiltonian $H_I$ and is varied "slowly" ...
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1answer
76 views

Direction of wave propagation unchanged after superposition?

It's quite confusing.Principle of superposition states that the amplitude of two superposing wave eqauls their indivisual amplitude vector sum.But what about direction.Souldnt't wave direction of ...
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4answers
275 views

Why is electrostatic force a function of the product of charges, not the sum?

When you have two forces , you ADD them to get the total. If both of us push on a car, the total force on the car is the sum of our forces. But, If we have an electron approaching another electron, ...
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3answers
177 views

Linear and non-linear systems

When I read about the superposition principle, it says that it works only on linear systems, my problem is that I cannot really understand the difference between a linear and a non-linear system. I ...
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0answers
101 views

Rules of addition of electric field

According to the principle of superposition of Electric Fields , we know that Electric fields add using laws of vectors. However while adding the electric fields , if for example one field is ...
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1answer
161 views

Is this assertion by Landau and Lifshitz's QM equivalent to the axiom that state spaces are vector spaces?

Many expositions of Quantum Mechanics begin by stating axioms of the following type: "The state of a quantum mechanical system is given by a nonzero vector in a complex vector (or Hilbert space) ...
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2answers
240 views

Neutrino flavor change in flight

I have read this article: https://profmattstrassler.com/articles-and-posts/particle-physics-basics/neutrinos/neutrino-types-and-neutrino-oscillations/velocity-differences-of-neutrinos/ https://en....
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3answers
206 views

Double-Slit experiment and the role of observation in the distribution

so I am still having difficulty understanding the role of measuring/observing the wave function. Many of the videos I have watched says that when we are not looking at the wave function it makes an ...
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0answers
41 views

Quantum theories related to superposition of entire events

If science, by accident or design, was to discover that the superposition of particles we already know of scales up to entire events (so different events are in superposition in the future, with some ...
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2answers
2k views

Can only one particle exist at a defined point in spacetime?

And for the contrasting question, may two or more particles be superimposed at the same point in spacetime?