Linked Questions

2
votes
0answers
43 views

Physical source of photon frequency [duplicate]

In QM it's taught that the frequency of a photon emitted when an electron drops from a higher-energy state to a lower-energy state is $\Delta E/h$. In E&M, it's taught that the source of an ...
282
votes
2answers
25k views

What is Chirped Pulse Amplification, and why is it important enough to warrant a Nobel Prize?

The 2018 Nobel Prize in Physics was awarded recently, with half going to Arthur Ashkin for his work on optical tweezers and half going to Gérard Mourou and Donna Strickland for developing a technique ...
23
votes
6answers
3k views

Why do electrons in an atom occupy only the stationary states?

When we talk about the elementary problems in quantum mechanics like particle in a box, we first calculate the energy eigen-function. Then we say that the most general state is the linear combination ...
8
votes
1answer
1k views

Can a quasiclassical electron wave packet in elliptic orbit be formed from bound hydrogen-like eigenstates?

Position probability densities of eigenstates of hydrogen-like systems have axial symmetry, so that the wavefunction too much resembles the circular orbits in Bohr's model. I'd like to have a ...
4
votes
3answers
2k views

Is there any time-dependent hydrogen atom Schrödinger equation, solvable analytically?

It's well-known that hydrogen atom described by time-independent Schrödinger equation (neglecting any relativistic effects) is completely solvable analytically. But are any initial value problems for ...
7
votes
2answers
847 views

Probabilities in non-stationary states

I'm confusing myself. Let's represent some state in the eigenbasis for Hydrogen: $$|\psi\rangle = \sum_{n,l,m}|n,l,m\rangle\langle n,l,m|\psi\rangle.$$ Now denote the initial state by $\psi(t=0)\...
7
votes
4answers
188 views

Can you shake a charged object fast enough to create light?

Electromagnetic radiation (a photon) is generated by an oscillating charged particle. Therefore, is it possible to vibrate an object at say 585 THz and create a green light source? Alternatively: what'...
0
votes
1answer
636 views

Cause behind photoelectric effect [duplicate]

In the photoelectric effect, a light ray of sufficient wavelength causes electrons to be released from metal surfaces. By what process do photons do that? In my textbook, I have seen that the photon ...
2
votes
3answers
3k views

Experimental verification for the de-Broglie - Einstein relation $E= h \nu$ for a particle

Is there any experiment that confirms the relation $E=h \nu$ for material(I mean the matter waves) objects? I mean, from the photo electric effect experiment, we came to know that photon carries ...
2
votes
1answer
3k views

To calculate the frequency of some wave source, does the wave source have to emit waves continuously?

I understand that the frequency is the number of waves that pass a place in a given amount of time. And it is shown like this: But, the frequency of waves are always shown above as if the source of ...
2
votes
3answers
299 views

Why does the universe need quantum superposition? [closed]

My question is not about the nature or reality of quantum superposition, superposition is a fact and no argue about that. My question is: What is the purpose of superposition and why does the ...
1
vote
1answer
800 views

How does the addition of two wavefunctions develop in time?

Two time dependent wavefunctions: $\Psi _1(t)= \psi_1*exp(\frac{-i * E_1}{\hbar}*t)$ $\Psi _2(t)= \psi_2*exp(\frac{-i * E_2}{\hbar}*t)$ Both a solution to the timeindependent (note "in") ...
4
votes
1answer
193 views

What would measuring the position of an electron in an electronic superposition look like?

In view of the Copenhagen interpretation, the state: $$\Psi = \frac{1}{\sqrt{2}}|0⟩ + \frac{1}{\sqrt{2}}|1⟩$$ is interpreted as "when the system is measured, you have a 50% chance of finding the ...
0
votes
1answer
524 views

Expectation value for the superposition of the two states (meaning of the imaginary part)

The wave function $\Psi$ of an electron that can exist in both states $n$ and $m$ is $$ \Psi = a\Psi_n + b\Psi_m \tag{6.28} $$ where $a^*a$ is the probability that the electron is in state $n$ and $b^*...
3
votes
2answers
338 views

What happens if you try to apply Maxwell's Equations to this quantum mechanical system?

In another post, we discussed the oscillating charge in a hydrogen atom and the weight of opinion seemed to be that there is indeed an oscillating charge when you consider the superposition of the 1s ...

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