# 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.

510 questions
Filter by
Sorted by
Tagged with
0answers
35 views

### If we solved the observer effect/problem, doesn't this mean Quantum superposition isn't actually real? [duplicate]

I am nowhere close to a physicist so please correct me anywhere I am wrong From what I understand about the observer effect, when we measure one intrinsic property of an electron such as position, ...
1answer
44 views

### Sequential Stern-Gerlach experiment

Consider the following diagram: (Sakurai) In the first lecture of MIT OCW Quantum Physics 1, 2013 (https://www.youtube.com/watch?v=lZ3bPUKo5zc), Allan Adams implies that if we remove the barrier on ...
1answer
21 views

### If two beams with orthogonal polarization states are superimposed, then how to evaluate the phase distribution of final beam?

Let the two input beams have different phase fronts and have orthogonal polarization states (say linearly polarized along x and y direction respectively). If these beams are superimposed, then the ...
5answers
2k views

### Can two waves interfere head on?

Can two waves (like sound or electromagnetic waves) interfere head on? If yes, and suppose they are out of phase with each other and thus interfere destructively, where does the energy of the waves go?...
4answers
769 views

### Doesn't the Schrödinger's cat inside the box cause the probability wave function to collapse long before a human opens the box?

My point is that there is no superposition of dead and alive. The cat will cause the probability function to collapse long before we open the box. What am I missing here? Isn't the cat capable of ...
0answers
26 views

### Are macroscopic superpositions possible in the presence of gravitational interaction?

Assume that it is possible to prepare a macroscopic system (say a 1kg iron sphere) in a superposition of two position eigenstates 1 meter apart. This experiment has to be isolated from the environment,...
2answers
107 views

### Are superpositions contagious?

Does quantum mechanics really predict that a particle prepared in a state of superposition of spin will result, after being measured by an appropriate instrument (Stern-Gerlach device), in a ...
0answers
29 views

### Confusion with mixed state [duplicate]

I have read that mixed state is a collection of pure states ...while a pure sate is a collection ie suoerposition of eigen states is that right?..so it can be thought of as a superposition of ...
1answer
67 views

### Understanding the quantum mechanical state vector

According to Griffiths, there is a general state vector $|s(t)\rangle$ that encodes the state of the system. He also says that we take $\Psi(x, \ t) \ = \ \langle x | s(t) \rangle$. Would then mean ...
3answers
78 views

### Is the concept of superpositions saying that the electron is actually in many states?

Basically when I read about it, yes. But I don't completely get why. Let me explain: If I throw a ball into a room and don't look, I would surely say that the ball is at one point in this room. Maybe ...
1answer
55 views

1answer
50 views

### Why are all solutions to this system of pendulum differential equations a linear combination of the two given solutions?

I am currently trying to do a lab report for a coupled pendulums experiment in which we find the following linear system of second order differential equations (describing the position as a function ...
3answers
88 views

### Examples of non-sine waves? [closed]

What would be a non-sine wave? AFAIK, all sound is a sine wave, equally to waves on the sea. What would be a common example of something in nature that's a wave but not a sine wave? Or, would we have ...
1answer
115 views

### Since pretty much everything is decohered, why we can even made superpositions in the lab at all?

We knew that one reason why most quantum mechanical experiments have to be done in a low temperature and isolated from environment condition is to preserve the coherence required for quantum states to ...
2answers
67 views

1answer
25 views

### How to see linearity of an interaction if it's lagrangian density is known?

The Lagrangian of electrodynamics is $-\frac{1}{4}F_{\mu\nu}F^{\mu\nu}+A_\mu J^\mu$ we know that electrodynamics is linear in special relativity but when we go to general relativity it becomes non-...
1answer
57 views

### Why waves in superposition pass through each other without interference in same medium?

Wave can interact constructively (add up) or destructively (cancel) but how about when they are in a superposition state why is there no interference when they meet up in same medium? Imagine 2 pulses ...
5answers
148 views

### Destructive interference of light and destroying energy?

I've had a hard time with destructive interference of light, and the possibility of destroying energy. I've read countless articles here and elsewhere, leaving me with the answer of something to the ...
0answers
46 views

### Scan Quantum mechanics: Status of current research

I recently stumbled on a new interpretation of Quantum mechanics, called Scan Quantum Mechanics, given by Beatriz Gato-Rivera. She suggests a quantity called quantum inertia, which divides the ...
3answers
44 views

### Intensity of the resultant of two complex waves [closed]

Suppose I have two waves: $Y_1= a_1e^{i(wt-kx1)}$ and $Y_2= a_2e^{i(wt-kx2)}$ I know by superposition $Y= Y_1+Y_2$ and intensity $(I) = |Y|²$ But how can I solve it. It seems hard for me to find the ...
0answers
51 views

### Superposition principle in Coulomb's law

My books says that "the principle of superposition is not at all obvious and does not hold in many situations , particularly in the case of very strong electric forces" . Why is that?
2answers
91 views

### Is reality really epistemological in its complete sense?

Taking the case of Schrodinger's cat, if the measurement of the cat is not yet done, then I don't know whether the cat is dead or alive. Epistemologically speaking, since I don't know about the ...
0answers
37 views

### Is it possible to compare two systems in superposition?

Is it possible to compare if two systems in a superposition are equal or not equal to each other, i.e. two systems with two electrons in superposition? At first: Superposition of two electrons (...
2answers
50 views

### Interpreting probability densities in atomic orbitals

I once read that an atomic orbital can be conceptualised as a cloud of "electron-ness". That is, the electron literally is the cloud, and the probability density only relates to the probability of the ...
2answers
76 views

### How do phase shifts affect standing waves?

So I understand that you get standing waves if there are waves of the same amplitude and wavelength traveling in opposite directions. But what happens if the wave traveling in an opposite direction ...
1answer
53 views

### Does superposition of all possible plane waves represent complete solution of Maxwell's equations in free space?

Consider the set of all possible superpositions of all possible "plane waves that satisfy Maxwell's equations in free space". Does this set represent all possible solutions of Maxwell's equations in ...
1answer
64 views

### Are there different types of superposition?

In electrostatics or in gravitational, when we are talking about interaction between multiple charges or multiple masses, we say that the interaction between any two charge or mass is independent of ...
1answer
111 views

### Why can't we superpose two quantum vacuum states?

i read in this paper (Spontaneous Symmetry Breaking as the Mechanism of Quantum Measurement by Michael Grady) that we are not allowed to consider the superposition of two vacuum states. i do not ...
1answer
38 views

### Deciding amplitude for Beats

I have two harmonic sound waves of nearly equal angular frequencies $\omega_1$ and $\omega_2$, and whose equations(which I have particularly modified for convenience), are $$s_1=a.\cos\omega_1 t$$  ...
3answers
1k views

### Do “fields” always combine by addition?

"Field" is a fun word which clearly has several meanings. In all fields I can think of in my learning career, the fields obey superposition. I can calculate the fields generated by each object ...
2answers
56 views

### Why the notion of degree of freedom is correct?

The intuitional definition for number of degrees of freedom is following: it is the minimal amount of numbers which allows us to describe the system's configuration correctly. For example, for dot ...
1answer
20 views

### Do quantum superposition occur at sound waves also like at Electromagnetic waves?

Like at the electromagnetic waves we see that they interfers the way like two different wave with frequencies can exist in the same place.