Theory Definition and 1000 Threads

Zermelo-Fraenkel Axioms - the Axiom of Choice (ZFC), is conceptually incoherent. To me, they stole Cantor’s brilliant work and minimized it. Replies?

Hello, i am new in condensed matter physics and studying the article 'Engineering artificial graphene in a two-dimensional electron gas' (Gibertini et al., 2009). I read a lot about bloch theorem lately and i got the main idea but still i don't understand the component of the equation. In the...

I've read in several places that some cosmological theories posit the existence of an "infinite number of universes" with laws of physics different from our own. I'm sure there's a lot of shortcutting in the reporting and "infinite" can't really mean infinite, can it? Wouldn't an infinite number...

Can a Bernoulli or Timoshenko model be reasonable for a crane arm, on ships? Yes, the arm might have a truss element, yes there is a hydraulic force to lift the arm (or cables). But to some extent, can one model the crane arm as one of a simple beam (either Timoshenko or Bernoulli -- and...

Homework Statement:: Violin String Shape Functions Homework Equations:: Violin String Shape Functions Hello, Is anyone working on violin string shape functions(Timoshenko Beam Theory)? It would be really helpful to my research if we share our knowledge on this topic. Thank you

https://www.google.com/amp/s/www.express.co.uk/news/science/1216872/universe-discovery-end-of-the-universe-finite-big-bang-theory-cosmos / amp

Are there any good images that can be used as a hook for an elementary number theory course?

Are there any good images that can be used as a hook for an elementary number theory course?

This is my first thread. I hope I do it right. I just started reading the book Special Relativity by W.Rindler. And as I was reading it, I stumbled upon a pickle. So in Lorentz theory, it says, supposedly we could measure the original to-and-fro time T2 directly with a clock, and suppose we...

Because I do have a background in the latter it was originally very difficult for me to understand some aspects of QP (quantum physics) when I initially learned it. More specifically whenever probabilities were involved I couldn’t really make full sense of it while I never had any problems...

Q：Which atom of CO molecule will bond with Fe in hemoglobin? discuss in MO diagram and theory. A : Because the antibonding molecular orbitals have more carbon character (carbon is less electronegative than oxygen), one would expect the bond to form through carbon. please tell me. Why we have...

Hi, I read a book on graph theory by West and is interested to learn algorithmic graph theory now.What algorithms are important in algorithmic graph theory in all fields such as planarity detection,1-factor ,hamiltonian cycle detection,finding eulerian tour,greedy coloring,graph realization

Homework Statement: See attached image. Homework Equations: ZFC set theory. Consider the text in the attached image. What is meant with "We require of an axiom system that it be possible to decide whether or not any given formula is an axiom."? Is consistency synonymous with soundness? Is...

I can see why it would be pretty illogical to speculate that physical constants change over time, but is there more to it than just being 'illogical' to assume otherwise? Is it axiomatic in physics to presume certain physical constants are constant, because otherwise stuff like atoms and things...

If I recall correctly it was in Adam Becker's book "What is Real?" where I read that late in life de Broglie took up again the pilot wave theory that he had introduced at Solvay in 1927 and that Bohm had done so much work on in the interim. Did de Broglie make any contributions to pilot wave...

Twistor Theory was once deemed as a viable unifying idea conceptualized by Sir Roger Penrose. However, is it now time to say that the theory is unofficially dead or does the idea still have merit against other unification theories?

I just read an article by Natalie Wolchover (a smart and knowledgeable writer as far as I can tell) in Quanta about the new analysis supporting a closed universe. In the article she makes this comment, "The leading theory of the universe’s birth, known as cosmic inflation, yields pristine...

Every theory, whether it is a physical, a psychological or a sociological theory, is defined in terms of an assumed architecture and in terms of a number of assumptions that apply within that architecture. An example from physics is the previously widely accepted dome theory to explain the...

I suppose my question is, since X commutes for H, does this mean that the selection rules are $$<n',l',m'|X|n,l,m>=0$$ unless $$l'=l\pm 1$$ and $$m'=m\pm 1$$, as specified in Shankar?

I am very new to such ideas but was wondering if there is any connection to what I am asking. Taking two events, let's say at opposite ends of the globe. Would even A, only have a potential on event B, if light could travel between these event in the given time frame of these event occurring...

Summary: Is "free will", as it is usually interpreted, a foundational assumption of QM? I've done a search using the term "free will" and have done a ctrl+f "free will" to go through those threads but I feel that the best way to find definitive clarification on my question is to ask specific...

Hi all, Group theory show us that irreducible representation of SO(3) have dimension 2j+1. So we expect to see state with 2j+1 degeneracy. But does group theory help to understand the principle quantum number n ? And in the case of problems with SO(3) symmetry does it explain its strange link...

Summary: How do I draw the HOMO of HO-. The problem asks about the HOMO of HO- interacting in different ways with the LUMO of H-Cl. I cannot proceed with the question without figuring out how to draw the HOMO of HO-. I have attached pictures. Hello All, I have been struggling with this problem...

Could MWI signify that there are not necessarily a (near) infinite number of real worlds, but rather that officially we can't tell if, or to what degree, the world we are in is real?

Dear Everyone I am having some difficulties on exercise 2e from Topology 2nd ed by J. Munkres . Here are the directions: determine which of the following states are true for all sets A, B, C, and D. If a double implication fails, determine whether one or the other one of the possible...

Are we ever π feet tall? If so, does that mean that every exact measurement is irrational? If we are not, is there a base unit of the universe?

http://sites.nd.edu/wtan/ take a look at the claims. and two published papers: https://doi.org/10.1016/j.physletb.2019.134921 https://link.aps.org/doi/10.1103/PhysRevD.100.063537

Dear Every one, I am having some difficulties on exercise 2b and 2c from Topology 2nd ed by J. Munkres . Here are the directions: determine which of the following states are true for all sets $A$, $B$, $C$, and $D$. If a double implication fails, determine whether one or the other one of the...

This may be a somewhat disorderly, unplanned out question, but nonetheless, I don’t know whether or not there exist any suitable academic advising websites that would be suitable for posting such. Would it be worthwhile investing time into learning theory of computation and automata via Neso...

[Edit 23.12.2019: A much extended, polished version of my contributions to this thread can be found in my paper Born's rule and measurement (arXiv:1912.09906).] Well, it is simpler than to introduce in full generality Born's rule. Everything can be motivated and introduced nicely for a qubit...

First I found the equations of motion for both fields: $$\partial_\mu \partial^\mu \psi = -\frac{\partial V(\psi^* \psi)}{\psi^*}$$ The eq. of motion with the other field is simply found by ##\psi \rightarrow \psi^*## and ##\psi^* \rightarrow \psi## due to the symmetry between the two fields...

For the diagram In scalar field theory, I have obtained an integral which looks like $$\int_{0}^{\Lambda} \frac{d^4 q}{(2\pi)^4} \frac{i}{q^2 - m^2 + i\varepsilon} \frac{i}{(p - q)^2 - m^2 + i\varepsilon}$$ I am required to calculate this and obtain the divergent amplitude $$i\mathcal{M} =...

First they got the higgs mass wrong (according to 2 independent measurements) but later they found a way to get the correct mass (after the mass already had been determined via LHC). https://arxiv.org/abs/hep-th/0610241 https://arxiv.org/abs/1208.1030 This looks too good to be true to me.

I'm looking for a book that describes the quantum field theory without going deeply in the theory with formulas or complex description of the mathematics under the theory. I know that this theory is really complex and it needs a deep knowledge of quantum physics in order to be understood. But...

what are the main concepts of membrane theory? the most beautiful possible giresults. g → 1/g where g is the coupling constant ive read that this transformation changes a dirichlet membrane into fundamental strings. does this have something to do with evaporation of black holes?

I have a doubt ,the thought experiment performed by einstein he thought that the clock was behind him and he is moving away from clock with speed of light what if he is approaching a clock with speed of light won't time run at very high speed

So, my apparatus consists of a basic wooden plank with a nail on one end and a guitar tuner on the other. I plan on using a heating lamp to control the temperature of the apparatus, which is placed inside an insulation box, and use a non-contact infrared thermometer to measure the temperature of...

Is it complete in the sense that there's nothing further to investigate in terms of its mathematical formulation? I mean, in the sense that we don't need to introduce new mathematical tools or review existing ones for the theory.

I am trying to learn group theory on my own from Schaum's Outline of Group Theory. I chose this book because there are a lot of exercises with solutions, but I have several problems with it. 1) In many cases the author just makes some handwavey statement and I have to spend hours or days trying...

What is the proper treatment of results about a formal axiomatized theory which are obtained from outside the theory itself? For example, there are 9 results dealing with the "≤" relation for Robinson Arithmetic, some of which are established by using induction, which is not "native" to Q...

Hello everyone ! I recently read an article about Standard Model's Lagrangian. And it made me remember another article (that I read a long time ago) which said that a theory's Lagrangian "represent" the theory. But How ? Maybe I didn't get the sense of "represent". Also I know that there is...

In quantum field theory, a dressed particle is a particle ("bare particle") considered in combination with certain secondary effects that it produces (e.g. the virtual pair creation involved in vacuum polarization). The dressed states are regarded as more physical, hence closer to reality. Axel...

In particular I would like to have a resource for the relation between group theory, crystal field symmetries and breaking of degeneracies of orbitals. I've taken a graduate condensed matter course and graduate quantum mechanics courses. I have some basic knowledge of group theory but can learn...

I have to solve the equation above. I haven't heard about an exact method so I tried to apply perturbation theory. I don't know much about it so I would like to ask for some help. First I put an ##\epsilon## in the coefficient of the non-linear ##\xi^2(t)## term: ##\ddot{\xi}(t)=-b\xi...

I was reading a forum post on a gaming website, and someone posted something I found interesting. Some have argued that it goes against scientific facts, specifically with regard to Quantum Mechanics. I don't know who's right, but I'd love to hear your thought on this? Human Wonder: "Random"...

Hi all. I'll get to the point. I've been interested in electricity since I was in college. Concepts such as current and resistance seemed easy to grasp for me but voltage remains a little bit obscure. It's thanks to this forum (specially forum members Jim Hardy r.i.p and SophieCentaur, sorry if...

So I heard a k-form is an object (function of k vectors) integrated over a k-dimensional region to yield a number. Well what about integrals like pressure (0-form?)over a surface to yield a vector? Or the integral of gradient (1-form) over a volume to yield a vector? In particular I’m...

Good evening. I wanted to study the theory about Fano resonances. I tried to read the paper but it doesn't seem very pedagogical to me and I coudn't understand all the details. Are there any notes or any good book where I can find a more precise theoretical description? Thank you

Consider a pair of entangled particles described by a local theory without hidden variables. Because there are no hidden variables, the results of an experiment on one particle of the entangled pair must be perfectly random. Due to locality, the particles also have no way of coordinating the...

Quantum theory is widely thought to be a theory of the fundamental microscopic constituents of matter. It is supposed to tell us something about how matter behaves at the fundamental microscopic level, from which the classical macroscopic behavior should somehow emerge as an approximation based...