Quantum and general physics Definition and 148 Threads

i want to know what is the most suitable quantum mechanics that will enables me after studying it to answer these specific questions ? i mean based on the hardness of these questions ( what book would you suggest to study these subjects ) . and by the way what is the level of these QM questions...

I have the calculation on secret key rate over the turbulence channel using Python code. The calculation is as below: import numpy as np import math import re import random import cmath #import itertools from math import pi,e,log import time #import xlwt import matplotlib.pyplot as plt from...

Did physicist John Archibald Wheeler propose the existence of multiple universes through his "It from Bit" or "Participatory Universe Principle" or "Law without Law and Pregeometry"? Is the multiverse related to Wheeler's ideas? I've been told that It can produce multiple universes, obviously...

Both Stephen Wolfram and nobel laureate Gerard 't Hooft think that the universe is a Cellular Automata. As far as I know, 't Hooft developped a series of frameworks to build different models of Cellular Automata and Wolfram also proposed a framework where network nodes could produce different...

In this article: https://arxiv.org/pdf/hep-th/0211048.pdf by physicist Andrei Linde, it mentions Wheeler-DeWitt equation and he relates it to Wheeler's Participatory Universe model. Also, I found other sources that seem to establish a connection between Wheeler-DeWitt equation and Wheeler's It...

Hello, The relationship between entropy ##S##, the total number of particles ##N##, the total energy ##U(β)##, the partition function ##Z(β## and a yet to be defined constant ##β## is: $$S(\beta)=k_BN \cdot \ln(Z(\beta)) - \beta k_B \cdot U(\beta)$$ Which leads to: $$\frac{dS}{d\beta} =...

The fundamental building blocks of the universe is thought of super strings, if proved can solve the mysteries of the universe but if proved than how? And how can it solve the mysteries of dark energy &dark matter and black holes?

The pure energy released from antimatter annihilation can there be any use of this clean energy for research purposes like the use of light in LIGWO for gravitational waves study can we use it efficiently like light in LIGWO I think we can and it could lead us to reveal mysteries of universe

Data = np.array([-1.61032636, -1.23577245, -0.50587484, -0.28348457, -0.18748945, 0.4537447, 1.2338455, 2.13535718]) print("Data is: ", Data) print(Data.shape) n,bins,patches = plt.hist(Data,bins=4) print("n: ",n) print("bins: ",bins) plt.savefig("./DOS")

It is easy to derive E=1/2mv^2 from the Schroedinger equation for the nonrelativistic one dimensional case where e^ipx-iEt/\hbar is the free traveling wave function: i\hbar x -iE/\hbar x e^ipx-iEt/\hbar = - - \hbar^2/2m x p^2/2m x e^ipx-iEt/\hbar which reduces to E=1/2mv^2 Where should I start...

Hello, I have some trouble understanding how to construct the matrix for the beam splitter (in a Mach-Zehnder interferometer). I started with deciding my input and output states for the photon. I then use Borns rule, which I have attached below: To get the following for the state space...

Hey all, firstly let me give some background, i`m a Cloud Computing Engineer and have been in the I.T. industry for the past 20 years since I left university. I have always had an interest in science and astronomy (My dad was a keen amateur astronomer) but never really taken it very seriously...

Can the low temperatures in Space be employed to cool a Quantum computer installed on an operational Space vessel doing away with the need of a super fridge or whatever they use here on Earth? Thank you.

In one dimensional system the boundary condition that the derivative of the wave function Ψ(x) should be continuous at every point is applicable whenever?

My question is: What is the contribution of Quantum Physics to the discovery, of the transistor? In Adam Becker's book What is real? I read that, "the discovery of quantum physics in the early twentieth century led directly to the [discovery] of silicon transistors..." He implies that, the...

The question is as follows: A particle of mass m has the wave function psi(x, t) = A * e^( -a ( ( m*x^2 / hbar) +i*t ) ) where A and a are positive real constants. i don't know how to format my stuff on this website, so it may be a bit harder to read. Generally when i write "int" i mean the...

So I love Quantum but unfortunately I don't have much idea of what its about. I would love to grasp the concept better. Can anyone discuss it with me?

When you look at a bird in a tree with binoculars, that is not the bird as it exists at the moment but the bird that was there before the light traveled to the scope, which for practical purposes is the bird. You can shoot the bird of before, and it will fall to the ground. However, when you...

I want to know more about quantum entanglement and I am a undergrad student in physics.Can someone suggest some research journals or articles to easily understand the concept deeply?

The electrons in a molecule are said to be in a quantum superposition state in terms of their position/spin/momentum. But when you look at a molecule like water at a chemical level, it has a very specific shape corresponding to the P orbitals of the outer shell of the Oxygen atom. The two...

In the paper "Steady-state spin synchronization through the collective motion of trapped ions" it states the following: "Steady-state synchronization of atomic dipoles forms the foundation for ultra-stable optical lasers utilizing narrow-linewidth atoms coupled to a lossy cavity mode. The...

If a wave function could be assigned to a whole galaxy, would its mass spread along the wave? Could this account for the anomalies in our calculations for galactic spin?

I've plotted out the trajectory of an imaginary electron in 3D; next I represent it's points with the matrix A(x1 y1 z1) "throughout it's orbit": ( -1/2 -1 1 ( -2 -1.5 2 (-1/2 2 3...

Can someone provide a clear basic description or reference to how the phenomena of synchronization manifests at the quantum scale? Thanks.

h is plank constant and v is frequency. I was using this to derive the TDSE. But I ran into problem because to substitute k^2 in E=h^2/8mpi^2 * k^2, I can use single derivative of psi squared or double derivative, both of which tend to give the correct answer. So, is my assumption of energy...

The Nature (Sept 4, 2009), (Science News, Oct. 24, 2009) article on the violation of Bell’s Inequality in Josephson phase quibits exquisitely demonstrated by Dr. John Martinis with his Martinis Group at UC Santa Barbara and Dr. Chris Monroe’s “Schrödinger’s Cat” demonstration with a Be+ ion...

Hello, dear scientists and forum users. I have recently finished programming the restricted closed-shell and unrestricted Hartree-Fock matrix equations. They seem to work fine for small diatomic molecules. However, I cannot understand the restricted open-shell theory that was firstly published...

Homework Statement Homework Equations I didn't get what this actually means. The Attempt at a Solution I'm not sure whether it is correct. Could you take a look? Regards!

What is exactly Weizsäcker's ur-alternatives theory? How is it related to digital physics theories? Is it related to pancomputationalism? Does it defend that a universe can be described as being fundamentally made of qubits? Would this mean that that universe would be fundamentally made by...

Can someone explain the meaning of the k vector and the general meaning of this equation?

Homework Statement The total spin of an Mg atom is zero and remains zero after absorption or emission of a photon. To which states can one of the electrons in the outer shell get by absorption of a single photon: 4s, 5s, 3p, 4p, 3d, 4d?2. The attempt at a solution I am not sure which of the...

hi guys i recently was reading about hawking radiation and how he overcome the lack of a theory for quantum gravity by using a mathematical trick ( to see the effect of gravity on quantum fields ) and this trick was the Bogoliubov transformation ... , i just want some one to briefly explain...

Homework Statement If a green laser is (wavelength = 532nm) sent through two slits with a separation of 127 um, how wide (in total) would the 11 green dots formed be if they were projected onto a screen 1.25m away from the slits? Refer to this diagram sorry for bad quality...

Homework Statement I have the wave function Ae^(ikx)*cos(pix/L) defined at -L/2 <= x <= L/2. and 0 for all other x. The question is: A proton is in a time-independent one-dimensional potential well.What is the probability that the proton is located between x = − L/4 and x = L/4 ? Homework...

Can anyone with basic knowledge of Dicke States assist with explaining how we arrive at equation (4) in the paper 'Entanglement detection in the vicinity of arbitrary Dicke states': <Moderator's note: link fixed> $$\langle J^2_{x} \rangle_{\mu} = \sum_{i_1,i_2} \langle J_{xi_{_1}} \rangle_{\mu}...

The time-dependent Schrodinger equation is given by: ##-\frac{\hslash^{2}}{2m}\triangledown^{2}\psi+V\psi=i\hslash\frac{\partial }{\partial t}\psi## Obviously, there is a laplacian in the kinetic energy operator. So, I was wondering if the equation was rearranged as...

Lecture Series: Character of Physical Law

Lecture Series: Character of Physical Law

Lecture Series: Character of Physical Law

Lecture Series: Character of Physical Law

Lecture Series: Character of Physical Law

Lecture Series: Character of Physical Law

Lecture Series: Character of Physical Law

The Fundamental Theorem of Quantum Measurement is stated as follows: Every set of operators ##\{ A_n \}## ##n =1,...,N## that satisfies ##\sum_n A_n^{\dagger}A_n = I## describes a possible measurement on a quantum system, where the measurement has ##n## possible outcomes labeled by ##n##. If...

I am studying about the cavity radiation inside a metallic cube. In the textbook it states that there are two independent waves corresponding to the two possible states of polarization of electromagnetic waves. What does it mean by this? (My current assumption is the phase change of the waves)...

The Fundamental Theorem of Quantum Measurements (see page 25 of these PDF notes) is given as follows: Every set of operators ##\{A_n \}_n## where ##n=1,...,N## that satisfies ##\sum_{n}A_{n}A^{\dagger}_{n} = I##, describes a possible measurement on a quantum system, where the measurement has...

The following, regarding quantum measurement, is stated in the paper "Limitation on the amount of accessible information in a quantum channel" : "Our discussion of measurement will be based on a specific physical model of measurement, to which we now turn. Suppose we have a quantum system ##Q##...

Hi ! I want to do research and publish a research paper on a topic related to physics . I am an undergraduate student , but I am much interested in research work. Kindly suggest me a topic on which I should do research ? And how much time will it take for the complete my research work ?

Hi, I have the impression that the special thing about Hilbert space for Quantum Mechanics is that it is simply an infinite space, which allows for infinitively integration and derivation of its elements, f(x), g(x), their linear combination, or any other complex function, given that the main...

1. A certain type of atom has only four energy levels, as shown in the diagram. The "spectral lines" produces by this element are all visible, except for one infrared line. The quantum jump that produces the infrared line is: (see attached file) A) state 4 to 3.B) state 4 to 1.C) state 2 to 1...