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.
Rovelli points to three pieces of existing observational evidence that should guide future quantum gravity research. Bottom line:
* abandon Lorentz invariance violating quantum gravity theories,
* abandon supergravity and string theory,
and
* stop working on the anti-deSitter/conformal field...
Could quantum entanglement be used to send faster-than-light communications across vast distances in space, in the distant future?
For example, if humans establish permanent colonies on Mars, it would take some time to send communications between Earth and Mars.
Could a future technology...
In Nielsen and Chuang p.223 we have the following situation:
$$\frac{1}{2^t} \sum\limits_{k,l=0}^{2^t-1} e^{\frac{-2\pi i k l}{2^t}} e^{2 \pi i \varphi k} |l\rangle$$
Which results from applying the inverse quantum Fourier transform to state ##\frac{1}{2^{t/2}} \sum\limits_{k=0}^{2^t-1}...
In HHL algorithm, does the controlled unitary (Hamiltonian simulation part of Quantum phase estimation) depend on Hermitian matrix coefficients and how?
I recently started studying some quantum mechanics, so far I have been using online resources(like MIT OCW 8.04/8.05, and Tongs notes I think I have reached a stage where I understand the Schrodinger eqn and can solve it for various potentials(including for the H-atom) but I don't know anything...
If I understand the idea of EPR correctly, the quantum entanglement occurs between two particles for which the total momentum is known (therefore, knowing the momentum of one particle, one can recalculate the other, and this contradicts the uncertainty principle). Then the question arises...
Are there any QFT books that use little to no math? If there is a little math that is okay. I don't know much about math. I am looking for good explanations on how it works without math. Any help would be great!
Im trying to obtain regularized (and triangulated) version of Hamiltonian constraint in the LQG. However, one step remains unclear to me.
I am starting with the Euclidean Hamiltonian:$$H_E=\frac{2}{\kappa} \int_\Sigma d^3 x N(x)\epsilon^{abc} \text{Tr}(F_{ab},\{A_c,V\})
$$
Now i have to...
"B0 is a static magnetic field (produced by a superconducting magnet) that initially causes the protons in the body to align with the field and precess at the larmor frequency along the z axis .
From a mathematical perspective this precession around the B0 axis occurs due to the time evolution...
A lot of people say that Quantum Field theory (QFT) an Quantum Mechanics (QM) are equivalent. Yet, I've found others who dispute these claims. Among the counter-arguments (which I admittedly do not have the expertise to pick apart and check their validity in full) are the following:
1) While QFT...
-1st: Could someone give me some insight on what a ket-state refers to when dealing with a field? To my understand it tells us the probability amplitude of having each excitation at any spacetime point, but I don't know if this is accurate. Also, we solve the free field equation not for this...
The charge associated with gravitational interactions is the mass. In the Standard Model, charge conjugation is the "flippin" of all kinds of charges (electric, color, etc). So, if we were to, say, incorporate quantum gravity in a beyond the Standard Model theory, what would the full charge...
I recently viewed a PBS "Space time" video
The video references two articles of which one is paywalled while the other is not.
https://iopscience.iop.org/article/10.1088/1367-2630/abb515/pdf
https://www.nature.com/articles/s41586-020-2490-7?proof=tIn the discussion section of the free article...
It came to my attention yesterday this, from my ignorant point of view, amazing paper that describes what it looks as another Theory of Everything: https://arxiv.org/abs/2110.02062
If I didnt understand incorrectly, from first principles / a pre quantum theory (Trace Dynamics, 8D octonionic...
I just finished a new paper,
A. Neumaier, Quantum mechanics via quantum tomography, arXiv:2110.05294.
(later renamed to)
A. Neumaier, Quantum tomography explains quantum mechanics, arXiv:2110.05294.
Abstract:
Starting from first principles inspired by quantum tomography rather
than Born's...
In p.385 of Griffiths QM the vector potential ##\textbf{A} = \frac{\Phi}{2\pi r}\hat{\phi}## is chosen for the region outside a long solenoid. However, couldn't we also have chosen a vector potential that is a multiple of this, namely ##\textbf{A} = \alpha \frac{\Phi}{2\pi r} \hat{\phi}## where...
Homework Statement:: Mathematics to understand Quantum Scattering Theory
Relevant Equations:: Suitable math book to understand Quantum Scattering Theory
I need to study Scattering theory from Introduction to Quantum Mechanics by David Griffith. But I think I need to study mathematics first...
I am looking for first articles of quantum gravity in the history which before Matyevei. What is earliest articles of quantum gravity and how can ı find them?
Ontology is the easiest and the hardest concept in the field of quantum foundations.
It is the easiest because even a child can understand it. When a child asks: "What is the world made of?", she asks about ontology. When you answer: "It's made of atoms" and when she asks "What does the atom...
I have been reading about ontologies in quantum physics recently and I came across Bohmian mechanics. If I understood it correctly BM endorses Particle ontology. Particle ontology claims that point-like particles that move continuously in time are the fundamental building blocks.
I know some...
This New Atlas article on Quantum Brilliance describes the development status of a new quantum data processor that can operate at room temperature. They are predicting a useful commercial device in about 5 years.
The device is based on nuclear spin in a diamond substrate.
The device is very...
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...
Take a simple case: A system is prepared in state ##\rho_i## at time ##t_0##, and a projective measurement is performed at time ##t_2## with an outcome ##b##. We can retrodict a projective measurement outcome ##a## at time ##t_1## where ##t_0<t_1<t_2##$$p(a|b) =...
An axiomatization of classical mechanics such as the one by McKinsey et al. (1) does not contain any reference to humans or experiments, and does not contain the magic (irony!) words of quantum mechanics, i.e. observables and measurements.
(1) McKINSEY, J. C. C., et al. “Axiomatic Foundations...
Hello! I see that most experiments applying quantum computing techniques for high precision spectroscopy use a quadrupole trap. I don't know much about the experimental implementation of these kind of traps, so any help (or suggested paper) would be appreciated, but I was wondering how well can...
Hello! I read several papers about using quantum information techniques in order to do precision spectroscopy on ions. Usually they trap 2 ions in a quadrupole trap and the 2 ions are coupled through their vibrational motion along the trap axis. However most of these results involve atomic ions...
They say spin up and spin down is correlated at at any distance and that it can’t be explained by basic logic.
say I rip a photo in two, shuffle them and put them in two boxes and send them light years away. No matter which box I open, I can’t know which half I have but when I open it the photo...
Summary:: The problem solutions contain a lot of unjustified steps, making them pointless.
I am trying to use Griffiths Introduction to Quantum Mechanics.
He states that the wave function ##\psi## approaches 0 as x approaches infinity to make normalization work.
I can accept that.
But then I...
Hello,
I am a high school student doing a project on pulsars and I would love to get into the deeper workings of a quantum electromagnetic field, but I am a bit lost. Since pulsars are neutron stars, who send out a beam of electromagnetic waves, I was quite curious about it's workings.
So...
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 had two questions in the field of physics:
We know that in quantum mechanics there is an electron in a certain distance from the distance to the nucleus as a cloud or a cover. But is motion for the cloud defined by the electron moving around the nucleus?
And the main question is, can the...
In the other thread of a similar name it was stated, and probably rightly so, that I wasn't using rigorous terminology or that I wasn't using them in a rigorous way. While I was making certain assumptions about the ability to interpret the 'jargon' I was using, it seemed to be a serious...
Hey, I found these interesting articles about a proposed way of vaccinating people while also applying a biomarker on them which would help remember one's vaccination status.
https://news.rice.edu/2019/12/18/quantum-dot-tattoos-hold-vaccination-record/...
I have a fidelity between the initial state and final state is 1 at t=0,1,2...etc. What does it mean physically? Does it mean that the quantum state is not evolved here. But In quantum dynamics every physical system evolves with time.
Greetings, I'm new here, I have an interest in the nature of reality, and a question.
Does the quantum spin of a particle (its intrinsic angular momentum) have anything to do with its wavelength and frequency?
One of the experts on Quora said no, and I cannot find anything about it on the web...
In this 1965 paper by Weinberg, https://journals.aps.org/pr/abstract/10.1103/PhysRev.138.B988, he describes a quantum field theory of the graviton in a Coulomb-like fixed gauge, where the free graviton has only space-space components and is traceless. This of course makes the field dynamics...
Is advanced quantum computing the key to achieving the world's first true artificial general intelligence? The astronomical amount of computing power required for an AGI is currently not possible with classical computing.
Continuing the discussion in the 'Assumptions of Bell's Theorem' thread, I'm hoping to explore the question of the location/position of the QM system prior to measurement.
I may have some bias or underlying assumption that is affecting the conclusion that I am drawing and, by exploring this...
fidelity for pure state with respect to t=0 is 1. My teacher told me this.
But I am not getting this.
This is my detailed question
the initial state(t=0)##|\psi\rangle=|\alpha\rangle|0\rangle##
the final state (t) ##|\chi\rangle= |i\alpha\sin(t)\rangle|cos(t)\alpha\rangle##
Fidelity between the...
I was teaching the basics of quantum states and was showing the students that an arbitrary state in a quantum two-level system could be written as ##|\psi\rangle = C_1 |+\rangle + C_2 |-\rangle = R_1 |+\rangle + R_2 e^{i \alpha} |-\rangle##, with {##C_i##} complex and {##R_i##} real.
Then...
https://arxiv.org/abs/2010.10345
My question is, Has the Feynman Diagram IIc been published or not?
Did Kroll & Karplus lie or not?
https://vixra.org/abs/2002.0011
Are these critics valid?
Please note: I am really a beginner in this field. If I write nonsense just let me know, I just gather information.
As far as I understood Quantum Computing is super fast but (this is basically my question) not suited to all kinds of engineering questions. As far as I know it should work best...
Hello! If I place a particle with more energy levels (of the order of kT) in a well defined state, in a thermal bath at temperature T, how will the blackbody radiation affect the internal state of the particle i.e. will the distribution be classical or QM? Basically, if I prepare that particle...