Quantum physics Definition and 728 Threads

Listen just 1 minute, what does it mean when he said nobody understand quantum mechanics? This sound like comedy

I think Atomic physics gets into specific examples and experiments but I think I’m probably wrong. So, I have to ask, what is atomic physics and how is it different than quantum physics?

I was taking notes from a lecture on Quantum Physics and during the introduction, they gave an example of what led to the discovery of Quantum Physics: The electric bulb example where the brightness and colour of light depended on the temperature of the filament(see...

I'm watching a nice video that tries to explain how linear algebra enters the picture in quantum physics. A quick summary: Classical physics requires that physical quantities are single-valued and vary smoothly as they evolve in time. So a natural way to model classical physical quantities is...

Hey everyone, A quick question that I hope all can participate: In your educated opinion, what is the biggest question or the biggest problem to be solved in quantum mechanics for 2023? Warm regards, Thiago Munhoz da Nóbrega

This trend is likely to drive a lot of misguided threads on science forums - IMO. Trend: https://www.cnn.com/style/article/multiverse-movies-newfound-popularity/index.html

Hello, I recently came across the following (apparent, I hope) paradox: suppose we have two H atoms. Now, a hydrogen atom is made up of one proton and one electron (fermions), so it is a boson. Then one could have two hydrogen atoms which are in the exact same state (including position). This...

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 was wondering what was the opinion of the physicist Nima Arkani-Hamed towards the Many Worlds interpretation. Is he open to the possibility of it being true? Does he support it?

I have a nanoparticle of cadmium selenide with a diameter d. When it emits a photon with a wavelenght lambda, it happens because an electron jumps from the conduction band to the occupied band across a forbidden band. I can suppose that jump as a jump from a higher energy level (the conduction...

I was not able to attempt since I don't know which formula or method can be used to solve the problem

This screenshot contains the original assignment statement and I need help to solve it. I have also attached my attempt below. I need to know if my matrices were correct and my method and algebra to solve the problem was correct...

I don't understand where I went wrong, the formula and calculations which I have attached are correct...please do help if anyone can spot the mistake.

I have attached my attempt and proof that my attempts were incorrect.

Hello guys, I don't know if this is the right place to ask, so please be kind :/ I have a question regarding the location of an electron that belongs to an atom. A teacher told me that the probability of an electron to be found within its orbital is around 99%. When I asked about the remaining...

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?

Homework Statement:: I came across the following in an online article. I am unable to understand how these elementary particles cause a force to exist. "Each of the four forces results from the exchange of force-carrier particles.". Above statement is taken from...

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 am considering the following Hamiltonian: $$H = -\Delta a^{\dagger}a + \omega_m b^{\dagger}b + g_0 * a^{\dagger}a (b + b^{\dagger})$$ which is the interaction picture optomechanical Hamiltonian for a cavity with movable end mirror. The mirror vibrations are quantized, leading to phonons that...

I am not an expert in quantum theory. I want to carry out some parameter estimation on a set of data I have. I have a model for the data with the parameter(s) of interest as variable(s). The data available is sporadic, meaning non-statistical or techniques involving no prior knowledge on the...

So for this question I just want to make sure that 1. Bohr model is that F_coulomb = F_centripetal? and then get w(r) is called determind? 2. for (b) calculate the frequency, should I use Rydberg formula or what?

I am trying to learn about quantum chemistry for the purpose of understanding electronic structures of nanomaterials, or perhaps more generally some theoretical computational approaches to understanding interactions of nanomaterials/small molecules and high energy (keV to MeV) radiation. I'm...

in classical physics, when a charged particle oscillates, it emits an electromagnetic wave, and the frequency of the wave depends on the frequency with which the particle oscillates. But in quantum physics, when an excited atom emits a photon, the energy of the photon depends on the magnitude of...

Continue reading...

Summary:: I’m a beginner trying to get into Quantum Physics, and want some good resources (e.g. books) to get me started. Hi everyone! I’m a beginner trying to get into Quantum Physics, and want some good resources (e.g. books) to get me started. I have a very basic knowledge of physics (10th...

Hello folks, I am currently studying from Griffiths' Introduction to Quantum Mechanics and I've got a doubt about good quantum numbers that the text has been unable to solve. As I understand it, good quantum numbers are the eigenvalues of the eigenvectors of an operator O that remain...

I am totally confused about the task. Any help will be nice. Thank you so much

Of course, this question consisted of two parts. In the first part, we needed to calculate the first-order correction. It was easy. In all the books on quantum mechanics I saw, only first-order examples have been solved. So I really do not know how to solve it. Please explain the solution method...

Is there a precise definition for the field? That is what I am after, since I am rather annoyed by the fact I currently do not have an unified view of the theory; having a one-liner helps me a lot in better understanding. So far there seems to be a split between an "old" quantum physics, which...

I read in an article that "Quantum physics is a highly mathematical theory that describes the nature of reality at the atomic and subatomic level". I also read another article that says quantum physics does not tell anything about reality. Can you give me some context about it in a way that is...

I was working on plotting fidelity with time for two quantum states. First I used discrete time( t= 0,1,2,3...etc) to plot my fidelity. I got constant fidelity as 1 with continuous value of time. Next I used discrete set of values ( t=0 °,30 °,60 °,90 °). Here I saw my fidelity decreases and...

I am a 14 year old who is very interested in Physics, especially astrophysics, but I don’t know exactly which math I should study in order to learn more in depth of the field. What is the best thing to learn?

Summary:: Any good english or german sources for Casimir effect, quantum fluctuations or zero point energy Hello, fellow quantum physicists I am currently writing a detailed physics script for my quantum physics project and I wanted to ask if you know some good internet sources on the theme of...

Summary:: Looking for ideas for my book about future QP applications. Hey everyone, I'm writing a sci-fi thriller set 25 years in the future, where my main character and his team are trying to stop an artificial superintelligence that is operating on the world's most powerful quantum...

In classical physics, we treat an electron as a point charge with a Coulomb potential ## V = \frac{q}{4\pi\epsilon_o r}##. However, in quantum mechanics, we treat it as an electron cloud. In this situation, how shall we describe the Coulomb potential? Shall we treat the electron as a charge...

Hello! I wanted to work first before I go to grad school for Ph.D in physics (especially in quantum). I wanted to work in a field close to quantum physics, but I was wondering if there were such jobs for those with bachelor's degree in physics?

I have a question that is related to categories and physics. I was reading this paper by John Baez in which he describes a TQFT as a functor from the category nCob (n-dimensional cobordisms) to Vector spaces. https://arxiv.org/pdf/quant-ph/0404040.pdf. At the beginning of the paper @john baez...

I am studying Quantum physics and I'm having some problems to understand what is the Wave Amplitude since I can't find a physical significance to it. Does anyone ever heard something that come close to a physical significance?

Are there areas of studies which could be characterized as an interface of biological physics and quantum physics? Does such an interface even exist?

Homework Statement:: I need a quantum physics book because I am learning it Relevant Equations:: Quantum physics I can borrow a pdf one

I've been studying quantum mechanics this semester in school and have ran into an issue I can't find an answer for. I understand why we take the complex conjugate of the wave function, such as when calculating expectation values. I'm a little confused though as to why we take the complex...

First, we can think a MZ interferometer as a combination of two beamspliter and a phase shifter(from MIT course "Atomic and Optical Physics II", the paper is "Quantum-mechanical noise in an interferometer"), which evolution matrix is B = {{1,-i},{-i,1}},B dagger and P ={{1,0},{{0,exp{i\phi}}}...

Jim explores what are the most popular interpretations of quantum mechanics and how we might need to be a little more specific when we talk about ‘reality’. Excellent layman's explanation of the Bell Inequality experiments.

Summary:: - IB Extended Essay - Physics - Quantum Mechanics and Electricity/ Electrical Components I've been asked to pick a topic for my IB Extended Essay. Basically the extended essay is a piece of independent research done during the course of IB. It's meant to be 4000 words and you have to...

If a singularity exists in the center of a black hole, could quantum physics, instead of relativity , explain it?

Summary:: My skills are very very basic and I'm more a networking major but i had to take a quantum mechanics class, i have trouble with this xcercise from textbook quantum mechanics a general introduction [Mentor Note -- Thread moved from the Technical forums so no Homework Template is shown]...

How did you find PF?: Searching a way to share own thoughts I was wondering if we could gather all the laws of the universe and try to link anything to everything. I'm thinking of the possibility of finding links between quantum physics and the theory of evolution. It reminds me of the...

Summary:: Looking for recommendations Are there any books on the philosophical implications of quantum theory by people who know what they're talking about?

The main message of this post is that quantum theory is local, that "``spooky action at a distance'' was just shicky Einstein's slogan from a letter to Born in 1947. Einstein directed it against the individual interpretation of a quantum state. This interpretation is often referred as the...