In physics, a quantum (plural quanta) is the minimum amount of any physical entity (physical property) involved in an interaction. The fundamental notion that a physical property can be "quantized" is referred to as "the hypothesis of quantization". This means that the magnitude of the physical property can take on only discrete values consisting of integer multiples of one quantum.
For example, a photon is a single quantum of light (or of any other form of electromagnetic radiation). Similarly, the energy of an electron bound within an atom is quantized and can exist only in certain discrete values. (Atoms and matter in general are stable because electrons can exist only at discrete energy levels within an atom.) Quantization is one of the foundations of the much broader physics of quantum mechanics. Quantization of energy and its influence on how energy and matter interact (quantum electrodynamics) is part of the fundamental framework for understanding and describing nature.
I got a one liner for QP, Electron behave like wave when no observer is there but when we put observer ELECTRON saw this and they told themself hey they are observing us lets change our behaviour, WE are particle now. That type of strange QP is. Am I right?
What i mean if we change state/spin at one end it will immediately effect the other. Can we see that live using two camera which may be 10 meter apart so that minium time delay. Is there any video proof exist such kind?
As QP says it is uncertain that where you found electron. But its not the same phenomena that one fan blade running so fast that you cant see where the blade is. You can only see the blade on a particular position if you use high resulation camera and its position depend on when you take the...
I have no idea where to start with this problem. I am interested in any hints, or ways to proof this. But i would especially like to know how the commutator is connected to the identity.
Suppose some quantum system has a Hamiltonian with explicit time dependence ##\hat{H} := \hat{H}(t)## that comes from a changing potential energy ##V(\mathbf{x},t)##. If the potential energy is changing slowly, i.e. ##\frac{\partial V}{\partial t}## is small for all ##\mathbf{x}## and ##t##...
Hello! I have two energy levels of opposite parity close by (we can assume they are far from all the other levels in the system) and an off-diagonal term in the 2x2 matrix Hamiltonian that weakly couples them. I initially populate only one parity state, say the positive one, and after a while...
Alain Aspect, John Clauser & Anton Zeilinger have rightfully received the Nobel prize for their contributions to quantum information, as they were three of the main pioneers of quantum information.
However, is it now impossible or very unlikely that other physicists working on this field (e.g...
I'm reading this article about quantum entanglement, and the author writes about a process in a Raman transition which would break the entanglement, and I'm interested about how it breaks the entanglement.
So the passage which I'm interested in begins with: "The answer is to do an operation...
Hi,
I have hard time to really understand what's a stationary state for a wave function.
I know in a stationary state all observables are independent of time, but is the energy fix?
Is the particle has some momentum?
If a wave function oscillates between multiple energies does it means that the...
Hi i have an quantum 5 binocular with 20x and 40x eyepices , is it possible to get other eyepices for this binocular who can fit with some adjustments ?
I found a paper (https://arxiv.org/pdf/astro-ph/0411299.pdf) which talks about quantum systems emitting energy due to spacetime expansion. Is this true or only a hypothesis?
My understanding of quantum theory and information theory is that, given complete information on the state of the universe at present, it is possible to predict its state at all times in the future and past. 3 questions: 1: is this true? 2: how are quantum-probabilistic outcomes accounted for...
Hello,
I hope you are well.
I have been doing a lot of readings on the wavefunction and have a question I did not see asked anywhere else in these forums. I was wondering if someone could shed some light on this for me?
I know the wavefunction is in 3N coordinate space and could be used to...
I'm curious what you guys think of the Nolting undergraduate physics series, particularly his 2 books on quantum mechanics? Are they sufficient? Are there any errors in them?
In a paper by Bain (2011), particles are left with little ontological value because of the Reeh-Schlieder theorem, the Unruh effect and Haag's theorem. The author claims (and here I am copying his conclusion):
First, the existence of local number operators requires the absolute temporal metric...
In classical electromagnetism I think I have understood the following(please correct me if something is wrong): A charge produces an electric field, a charge moving with constant velocity produces a magnetic field, an accelerating charge emits electromagnetic radiation. In radio antennas this is...
I apologise for my very limited understanding of quantum physics: my background is in General Relativity. A wave function is said to represent the probability of a particle being at some point in space/time, and I take that to mean that the probability of a quantum event is a density on...
So, I am doing a Uni project with Planck's constant. What I need to do is determine Planck´s "quantum action" with help from the Photo effect and reverse voltage method. The thing is that I have never learned Quantumphysics or stuff like that. So, what and where should I begin to learn?
(Sorry...
What is it of the photon that gets polarized from a quantum mechanical perspective? In the classical perspective it is often thought that it is the oscillating electric field that gets polarized. But in the quantum case: Is it the de Broglie wave function? Or is it the spin and in case it is the...
The editors of high impact journal Nature Physics explain why the field of quantum foundations is important for physics.
https://www.nature.com/articles/s41567-022-01766-x
Hello, I'm hoping someone can help me understand a statement in Sakurai Modern Quantum Mechanics (3rd edition).
In particular, in the section that describes free particle in infinite spherical well (page 198, section 3.7.2), after the text has shown that for a given ##l## value, the energy...
So this expression is apparently in Sz basis? How can you see that?
How would it look in Sy basis for example?
The solution is following. They are putting Sz as a basis, bur how do you know that Sz is the basis here?
Thanks
As I was looking for an example for a metric tensor that isn't among the usual suspects, I observed that the Cartan matrix I wanted to use is positive definite (I assume all are), but not symmetric. Are the symmetry breaks in quantum physics related to this fact?
I can't figure out how they get i/sqrt(2) for normalisation of c1. Why is it a complex number? If I normalise c1 I just get 1/sqrt(2) because i disappears in the absolute value squared.
Thanks
I'm a M.Sc physics student and I need to use quantum espresso for my research project . I tried the same procedure I used to install it on the system at home as I did for the one at the College but i keep getting the same error . I can't find why . I'm also new to linux .
I'm using ubuntu and I...
Greetings,
Given an infinite universe or an infinite number of universes?
- Regarding the location of an electron around an atom, is there a tiny volume in which finding the electron 100%? Or is there a possibility, no matter how remote, it might be found a meter away or a kilometer away?
-...
I'd like to understand how gravity does not combine with quantum mechanics. At least there is no accepted theory of quantum gravity, so I assume it is not solved? I'm only starting to learn QFT and eventually GR. Maybe, someone can already outline where those theories fail to combine and comment...
I am reading a popular-science book Reality Is Not What It Seems by Carlo Rovelli, one of the founders of loop quantum gravity.
He writes:
and
and
So basically, space (spacetime) is just another quantum field like all the others, and the quanta of this field is the nod. Nods have volume...
I have a question regarding the storage capacity of quantum computers. I read that 32 qubits (4 "quantum bytes" if you will - not sure if that's an actual term or not yet) can store the equivalent of 500mb of data.
Is this directly proportional? I.e., would 8 qubits store the equivalent of...
I am learning Dirac notations in intro to quantum mechanics. I don’t understand why the up arrow changes to down arrow inside the equation in c).
My own calculation looks like this:
I have a lecture slide that shows how to find S_x and S_y. I get all the steps except the last row.
Where did 1/2 come from? I think my linear algebra needs polishing.
Thanks!
According to professional scientific literature and to our best understanding, are there any suggestions that entanglement might imply some sort of faster than light signaling between the entangled particles?
I know that according to relativity nothing can travel faster than light, but what...
Hi Pfs,
When Stephen Hawking proposed the idea of black hole information it appeared that information could be lost. it was a problem in GR which is a dererminitic theory. Knowing initial data and Hamiltonian tells you what was and will be.
It is not the case in quantum physics. things evolve...
I watched a video on the topic by Sabine Hossenfelder.
Now it is said by many that this proves the photon "knows" something in advance because a certain state of a certain beam splitter can be probed in theory without the photon ever encountering that beam splitter because it took another path...
Assume I could produce a stream of calcium ions from a 2nm diameter nanotube by pushing them through the nanotube using coulomb repulsion. Assuming these coulomb repulsed ions produce a stream of entangled ions which then create a slowly emitting quasi static electric (near) field.
Even if...
I have just finished my course on electromagnetism. Due to my performance, the professor has contact me for congratulations and asking, if i want, to join his quantum optics course for graduate students.
Even so i think it is interesting to follow the advice, i am a little afraid if this...
A macroscopic object has the order of Avogadro’s number of particles. That’s over 10^23. So the probability of all of them tunneling, at the same time, is on the order of that original small probability, to the 10^23 power. And then on top of that, you have to factor in the chances of it...
Hi PFs,
I am reading this paper written by carlo Rovelli:
https://arxiv.org/abs/1010.1939
there are many things that i fail to understand, but i would like to begin with a simple thing.
Rovelli write that:
It is locally Lorentz invariant at each vertex, in the sense that the vertex amplitude...
Quantum gates must be reversible.
The usual justification for this is that in QM the time evolution of a system is a unitary operator which, by linear algebra, is reversible (invertible).
But I am trying to get a better intuition of this, so I came up with the following explanation:
In order to...
I'm wondering about some aspects about black holes (BH) and singularities, but since all my questions have to do mostly with quantum mechanics, I placed this thread in here.
OK, let's assume there IS a singularity in the middle of a BH.
A) Pauli exclusion principle (PEP) says no two fermions...
Heisenberg is regarded as a major figure of the Copenhagen interpretation. In a certain degree, he is influenced by Logical positivism.
Despite of that, has he any ontological commitments regarding the Quantum theory?
Or, he considers the Quantum theory merely as calculation procedure for...
Quantum spin is orientable so it takes place in a space with an even number of dimensions. What is that space?
If the space had an odd number of dimensions, then spin in that space wouldn't be orientable. But quantum spin is orientable.
We could say that it is Minkowski space, but that space...