Theory Definition and 1000 Threads

just below eqn 3.25, it is said: At any given time, Ex is constant for all values of x, but of course, this possibility cannot therefore correspond to a traveling wave advancing in the positive x-direction. Why can't Ex be a constant?

I'm sure you are familiar with Le Sages physics and how it predicts gravitational drag. But what if no velocity vector matters except the direct line between the two gravitational objects? Does this fix Le Sages theory?

Hey guys I figured out something new about color theory in additive color mixing. So, the primary colors in additive color mixing are R, G, and B (Red, Green, and Blue). The secondary colors are C, M, Y (Cyan, Magenta, Yellow). Using basic knowledge we know that R + G = Y R + B = M G + B = C...

I just want to verify from physicists whether what I have read in this article is true: http://www.astro.ucla.edu/~wright/infpoint.html It says: The Universe was not concentrated into a point at the time of the Big Bang. But the observable Universe was concentrated into a point

I know that mie theory is used to analyze the absorption/scattering/extinction of a homogeneous sphere within a homogeneous dielectric medium. However, if I wanted to perform the same analysis on a sphere enclosed by two different media, is there an analytic solution to this?

On page 30 of the notes (https://arxiv.org/abs/1501.00007) by Veronika Hubeny on The AdS/CFT correspondence, we find the following: So far, we have been describing just one particular case of the AdS/CFT duality, namely (3.3). There are however many ways in which the correspondence can be...

So I've been reading David Bohm's original paper on the alternative interpretation of quantum mechanics in terms of hidden variables, just out of interest. In the 4th section he presents a complex function ψ in terms of R and S, and then (using the time dependent schrodinger equation, TISE)...

Homework Statement this problem came out in the math olympiad i took today and i got completely wrecked by this consider the following equation where m and n are positive integers: 3m + 3n - 8m - 4n! = 680 determine the sum all possible values of m: Homework Equations not sure which The...

Where is the electron-nucleon interaction? On the surface of the nucleus, or at the origin (R-0) ?

I am a cosmologist/theoretical astrophysicist, and so far my research (all 2 years of it) has focused on quantum cosmology. However, I have become interested in string cosmology recently, and wish to do some work in that field. Obviously though, there is a minor problem with that idea. Learning...

Hi , in the classical course " nuclear reactor theory we treated neutrons as particles. can we treat neutrons as waves when it comes to diffusion or transport equation ? neutrons flux/ cross-sections ? I googled it and I didn't find enough info. Like there a lot of common terms between quantum...

This is a general question (maybe stupid). I am very interested in Double Field Theory, Exceptional Field Theory, Generalized Geometry and Non-geometries in general and I would like to do my PhD in this field. I know that it is quite popular at Imperial College London and at Max Planck...

Homework Statement [/B] 1) Is the order paramter ##\phi(x)## intensive or extensive? 2) Is ##M## intensive or extensive? With the following definitions : Homework Equations The Attempt at a Solution 1) Free energy is extensive, however I don' think I can use this to deduce whether...

In string theory, particles is vibrating strings. However, QFT treats particles as excitations in a quantum field. Can both of these theories be correct? If so, how does them fit together?

1. Homework Statement Question (with the following definitions here): - Consider ##L_0|x>=0## to show that ##m^2=\frac{1}{\alpha'}## - Consider ##L_1|x>=0 ## to conclude that ## 1+A-2B=0## - where ##d## is the dimension of the space ##d=\eta^{uv}\eta_{uv}## For the L1 operator I am able...

I have known: (1) A Hamiltonian, say, H(k), where k is the crystal momentum. (2) An appropriate complete basis set {a_1,a_2,a_3…}. (3) Some symmetric operators {A,B,…} which commute with H(k), i.e. [A,H]=[B,H]=...=0. Of course, by calculation, I can get any matrix element of H(k), i.e...

How do I show that the payoff function πi isn´t continuous? Why do best replies not always exist?

If there is a "theory of everything", a single equation that basically explains everything, why should be study Astrophysics, Condensed matter, or so? I mean we should rather study String Theory, Quantum Gravity... So, am I wrong? Maybe I'm leaving some important details.

I'm looking for a recommendation for an up to date, introductory String Theory text and an overview of the prerequisites. Thanks in advance.

Homework Statement I am reading Dummit and Foote, Chapter 13 - Field Theory. I am currently studying Section 13.1 : Basic Theory of Field Extensions I need some help with an aspect of Exercise 1 ... ... Exercise 1 reads as follows: Homework Equations Relevant theorems for this exercise...

I am reading Dummit and Foote, Chapter 13 - Field Theory. I am currently studying Section 13.1 : Basic Theory of Field Extensions I need some help with an aspect of Exercise 1 of Section 13.1 ... ... Exercise 1 reads as follows: My attempt at a solution is as follows:p(x) = x^3 + 9x + 6 is...

Hi! I'm struggling with these two problems: 1. If for whichever two vertices a and b in the graph G there is only one simple path from a to b, then the graph is a tree. Eh... isn't this part of the definition for a tree? I really don't even know where to start with proving this statements...

in string theory, where strings are posited as fundamental entities, what is the relation between eletrons muons tau how does string theory explain the increasing masses of leptons how do these leptons other properties come about in string theory what about the antiparticles of each? i.e...

This is no homework for me. I am working as a teaching assistant in a lecture about logic and discrete structures for Informatics students. This should be a piece of cake, but I am not exactly sure of the logic behind. 1. Homework Statement Translate into words ∃c . ∀a ∈ A . ∀b ∈ B . ¬(a =...

Homework Statement I am solving a question that asks for, what's the minimum coefficient of friction required for a cylinder to roll without slipping? Where the cylinder has a force F acting on its center. Homework Equations And The Attempt at a Solution From the way I understand it, the...

For chemical experiments that involve gases as reactant and products, gas tube are used for their transport. Q1. Why are there differences in length of gas tube when in a round flask. In most case, entering tubes are longer than exiting tubes? Why is that? Q2. Why is sometimes the entering...

From time to time, I point to string theoretists that they should have considered more seriously to use Kaluza-Klein theory and they invariably answer me "we do", and move forward. So I am starting to thing that perhaps I am wrong and I have missed some developing of the theory the the XXIth...

1-Whats the relationship between entropy and İnformation ? 2-Can Entrophy always increases statement imply information lost ? 3-If it implies how its lost ?

Over the last couple of years there has been allot of traffic on youtube about the sum of all positive integers being equal to -1/12 as is explained in numberphile video. Some argue that their calculations are wrong and the sum really is infinity. In their original video numberphile shows a...

Hello friends. I'm trying to compute an EoS to walecka model of barion interaction, but I'm having trouble to solve this equation by bisection. M*=M-gs²*nb/ms² where nb= (M*)*( kf*Ef- (M*)²* ln (kf+Ef)/M*) , using Ef= sqrt( kf²+(M*)²) and Cs²= gs² M² / ms² = 267.1 I'm using J. D. Walecka...

Horgan: Do you still think string theory is “not even wrong”? Woit: Yes. My book on the subject was written in 2003-4 and I think that its point of view about string theory has been vindicated by what has happened since then. Experimental results from the Large Hadron Collider show no evidence...

I'm fairly new to QFT and I'm currently trying to understand perturbation theory on this context. As I understand it, when one does a perturbative expansion of the S-matrix and subsequently calculates the transition amplitude between two asymptotic states, each order in the perturbative...

Hi, i would be curious to know what would be the prerequisites for learning the classical field theory !

Hello, I am new to this. As I understand it, the difference between the quantum field theory and string theory is that in the former, physical field is considered as the fundamental reality, while in the latter it is believed that everything comes out of strings. My question is, by everything do...

There seems to be a lot of conflicting research on nuclear winter theory, especially since the 1990s. Carl Sagan famously predicted that the Kuwaiti oil well fires from Operation Desert Storm would result in a small global winter, but the effects turned out to be more localized and less severe...

Hello! I read some stuff about "attempts" to test some aspects of string theory at LHC and I was wondering if there is any deep reason behind the conservation of energy in general or it is just based on the fact that it holds in all the experiments (excluding uncertainty principle arguments)...

This question is directed to all the professors who have supervised PhD students in high energy theoretical physics. What attributes have you noticed (during your years as a supervisor) among PhD students who later went on to have great careers in high energy theoretical physics and made a name...

Homework Statement STATEMENT ##\hat{H}=\int \frac{d^3k}{(2\pi)^2}w_k(\hat{a^+(k)}\hat{a(k)} + \hat{b^{+}(k)}\hat{b(k)})## where ##w_k=\sqrt{{k}.{k}+m^2}## The only non vanishing commutation relations of the creation and annihilation operators are: ## [\alpha(k),\alpha^{+}(p)] =(2\pi)^3...

Hi everyone, So I recently read a chapter in a math book that vaguely describe how connections on bundles occur in particle physics, but they are very cryptic about the physics part and I just want to know a little bit more about it. So I'll tell you what I read and then follow up with some...

Homework Statement hello, I have this graph and i have to figure out these so to speak characteristics. 1) find incidence matrix 2) arrange peak according to rank and layers 3)draw new arranged graph 4) find new connection matricies of peaks and arcs Homework EquationsThe Attempt at a...

so this is the question: let a and b be real numbers such that 0<a<b. Suppose that a3 = 3a -1 and b3 = 3b -1. Find the value of b2 -a. initially my line of thinking was that just solve the equation x3 - 3x +1 = 0 and take the roots which are more than 0 and then after that i got stuck ok that...

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Firstly an apology...I don't know what level my question should be aimed at and what forum it should be set in and I think that level A and Quantum Physics are as good as guesses as any. Moderator please moderate if necessary. It's about constructor theory, something that I wouldn't normally...

Let us consider a classical field theory with gauge fields ##A_{\mu}^{a}## and a scalar ##\phi^{a}## such that the Lagrangian is gauge-invariant under the transformation of 1. the gauge fields ##A_{\mu}^{a}## in the adjoint representation, with dimension ##D_{\bf R}##, of the gauge group...

Hi all, I am struggling the question, please see attachments. Thanks a lot Devise an algorithm which, given a (directed) friendship graph (in the xkcd format), finds the optimal seating arrangement. Your algorithm should include the following:  a description of the required input format...

Homework Statement I have an exercise that I do not know how to solve. ##N## is a nucleon field, in the fundamental representation of ##SU(4)##. We want to classify operators by their ##SU(4)## transformation properties, bearing in mind that the nucleon is a fermion and we need antisymmetric...

Hello! I read several books and took courses on quantum mechanics and particle physics and I understood the topics. However I feel that I have only pieces of informations without a global image of what is going on. For example in the particle physics classes we were given Feynman rules without...

Hello people, I'm really interested in non-mainstream physics but so far i can't find a place./forum where i can discuss or share theories. I've tried doing it in the Quantum Physics section, but my thread was rejected because personal theory developments are not allowed here. So far it's ok...

Is it possible to associate electric and magnetic fields with the vibrating string that is thought to represent a photon in string theory? Thanks!

Homework Statement The problem consists of 2 parts,the first one(I have done it) is on the following website: https://www.physicsforums.com/threads/transition-probability-from-two-states.804343/ Q1: I calculated the desired result p(t) = sin^2(Ut/h). However,I don't understand why <1,t | 2 >...