Theories Definition and 486 Threads

Hi My name is Virendra Singh Rawat, I am 63 years old male, staying at Indore, India. I did my B.Tech in Metullurgy from IIT Kanpur, India in 1985. I have no formal qualification or training in any dedicated field. I am fascinated by sky and love to see the dance of heavenly bodies. For 20 years...

So I've seen that radar can be used in space which is interesting and brings questions to mind as well as theories. Unrelated Sonar which uses sound waves don't work as sound isn't transmittable through space. Questions: 1) What techniques are used in radar to prevent "wondering" or the radio...

Hi. The numerical value of the speed of light ##c## pops out as propagation speed of the wave solutions to Maxwell's equations. It seems like everywhere else we need to plug in ##c## as a parameter. Why is that? Is there a way to "derive" the numerical value of ##c## in other theories, that...

Books like Griffith, Martin, and Perkins are best if I consider them for the thorough history of particle physics.

Hi, all! I'm currently studying the 3 families of leptons. 1) Are there any accepted theories about why the lepton masses are what they are? 2) What are the best journals to read about this kind of thing? I'm aware of the Koide formula, but that seems to be an empirical formula, not a theory...

Hi, Fairly new to the forum, but trying to post some ideas on new ways to look at gravity, but not sure where the correct place is. Where is the best place to discuss new ideas please? John.

I have my own thoughts and possible could provide sketch or instance use case, elaborate using evident setsettings. But I don't want to persuade, influence or lead other people who are actually educated and inadvertently guide and ultimately hinder the outcomes of their initial assessment. The...

Hello, As a layman in physics, I wonder the ideas of people who have more knowledge in physics than I do about the theories of Swiss Physicist Nicolas Gisin and his arguments about the intuitionist mathematics. Is there a way to reconcile these ideas with more fundamental theories like SR and...

Hi, you all, I have been for a couple of semesters interested in quantum gravity as a problem, but truth is I never have been properly introduced to any of the candidate theories. Actually, there are multiple candidates and I would like to compare them. The question then is the following: do...

This thread picks up a discussion between myself and @A. Neumaier in another thread. In particular, this comment: Reference: https://www.physicsforums.com/threads/nobody-understands-quantum-physics.1049370/page-8 First some basic background. If we consider the usual presentation of a...

In the paper https://arxiv.org/abs/1210.4699. How to solve this equation? I've tried it, it's not same as in this paper. Even zero order still not the same. This is what I try to do at zero order. input $$E=E_0\left(r_0\right)$$ $$H=H_0\left(r_0\right)$$ $$b=b\left(r_0\right)$$...

https://academicminute.org/2022/11/joel-frohlich-university-of-tubingen-how-to-spot-pseudoscience-in-an-age-of-conspiracy-theories/

My article has been published in Quantum Reports. Expanded abstract: There is currently no consensus on the interpretation of quantum theory, so this article may be of interest as it contains a review and new results on some relevant mathematical models emulating well-known quantum theories...

In 1968, Lord and Novick published a book called Statistical Theories of Mental Test Scores. I wonder why they used the adjective 'statistical'. Does this suggest that the theories mentioned are not psychological theories and, if so, what could be the meaning of such theories? Should these...

Along with the endless complexities of life and the evolution of life, it occurs to me that at all points there had to be enough available nutrition for existent life forms - and that food supply itself had to go through a process of evolution. It seems self-evident that the environment of early...

I recall that there was an argument from Born expansion showing that exchange of odd spin between equal sign charges generates a repulsive potential, and if the charges are different or the spin is even the potential is attractive. I wonder, how does it work for non abelian gauge theory...

What is it called went to different theories (or kinds of theories, apparently) overlap in their explanations over major parts of their explanatory field and you want to talk about the area of overlap in the phenomena they explain? Classic examples: Newtonian physics vs. relativity, similar...

Free Kindle via Amazon, both part 1 and part 2 Part 1: https://www.amazon.com/dp/B00OD49Z96/?tag=pfamazon01-20 Part 2: https://www.amazon.com/dp/B00OD49Z00/?tag=pfamazon01-20 Enjoy

Is there a book or article that discusses the scalar/tensor/scalar-tensor (maybe others as well) theories ? (Look at this wiki page for a general overview of the theories that I am talking about) So, I am looking for a book that discusses these theories either in general or in detail. It does...

Summary: Recent world wide acute hepatitis outbreak in children and possible etiology. I've watched these cases with much interest lately, particularly since some of the possible vectors are being studied and identified. As the theories are being explored as to the cause, or causes of the...

I recently watched this video by David Tong on computer simulation of quantum fields on lattices, fermionic fields in particular. He said it was impossible to simulate a fermionic field on a lattice so that the action be local, Hermitian and translation-invariant unless extra fermions get...

I have heard of and read about the big bang theory for the start of our universe. Are there other competing theories that I should look at. Thanks Chiefly

Hi, I am looking for a book exploring the current theories of physics and their fundamental interactions. As we know, each fundamental theory is associated to a specific interaction. I wish to explore this tree of theories and see their links. Thank you

This is asking for suggestions for freely-available serious on-line sources (with links) for criticism of the theories of Erik Erikson. Details: The neo-Freudian psychologist Erik Erikson https://en.wikipedia.org/wiki/Erik_Erikson was and remains quite popular. However, looking through his...

Is there an up to date list of all cosmological theories resource which provides some or preferably all of the following information: Which theories are considered speculative and even highly speculative? (degree 1 to 4) Which theories are still actively being worked on and roughly how many...

I was reading recently about string theory recently which postulates that there are 11 dimensions representing all possibilities for everything. This is an interesting theory, although very difficult to prove and therefore somewhat speculative in my opinion. [Ed.: personal speculation removed]...

Hello:) Our homework is done through mcgraw hill connect. I am able to see the solution to the problem and it contradicts what the book and powerpoint says. according to the powerpoint given by my professor, moors circle, sigma1 = Sy or yield strength. Powerpoint also states that sigma(x) is...

Hello All We have Newton's Laws of Motion, which have been superseded by Einstein's Theory of General Relativity. Who determines what's a Theory and what's a Law? best regards ... Stef

Some physicists (like John A Wheeler, Holger B Nielsen or Ilya Prigogine) have proposed that all the laws of physics (including the most fundamental ones) emerged from a primordial chaos (for example, in the case of Wheeler, he proposed that laws of physics emerged from an initial random and...

Hello. Do you know why some theories in physics are falsifiable?If we take for example Newtonian gravity and general relativity, we see that a more exact approximation or theory in physics can be proposed. Why does this happen? More phenomena can be described from the new approximation, but...

As per the summary I would like to find a review paper, monograph or book. Google is not find any recent reviews. Post 2018 would be ideal. Thanks for any pointers. Regards Andrew

I have seen several attempts at building a consistent quantum-classical theory, i.e., a theory where a quantum (sub) system interacts with a classical one somehow, and both affect each other (do note that this definition rules out things like just plugging an external classical EM field into the...

Perhaps the reason is that the principle of least action is elevated to a divine principle that does not require materialistic interpretation. If so, then the solution to the "secrets" of quantum theories lies in the solution of the materialistic essence of the physical magnitude of action.

There has been a lot of talk about the value of beauty in theoretical physics. There seems to be a lot of little things that are beautiful because they make sense, according to what we already know, like the discovery of anti-particles, and recently the Higgs. The standard model was revealed...

[Moderator's Note: Thread spun off from previous thread in General Discussion since it is more specifically about particular scientific theories and how to test them against data.] So in your opinion, everything in the list below is quantitative, not qualitative...

Hey there.Have you read about the alternative theories proposed by other scientists to General Relativity?So far General Relativity still stays the most accurate.But if we could generalise it?Perhaps try with some new maths like complex differentiable manifolds or Lie groups or another...

it seems to me that in math don't exist false theorys,missconcepions or examples where after 200years some theory prove that was false like in physics do...etc do you know that in most high school aerodynamic books last 50 years lift is explain with "equal transit time" theory which is...

I just read an article I found very interesting, about the psychology of and possible reasons for conspiracy theories: What we can learn from conspiracy theories (BBC, 25th May 2020) http://www.bbc.com/future/article/20200522-what-we-can-learn-from-conspiracy-theories "From political upheavals...

What distinguishes discussions of the what-ifs of history from forum-prohibited discussions of personal theories and speculations? My thoughts: 1. Academic historians do discuss the what-ifs of history. 2. Speculations about things that might have happened can clarify the significance of...

I have lately been reading, with interest, the history leading up to Einstein's work as well as some of the debate that ensued after his theories were published. In particular, I was reading some of the ideas Ritz proposed and the disproof of his theories by de Sitter. A question occurred to me...

My background is in fluid dynamics. Controlling high velocity fluids via atmospheric and offset dynamics. I have put some evidences together, for discussing a new working principle theory. These simple experiments, along with known experiments found on YouTube, come to be a very interesting...

Summary: The key to unifying the theories of the very large and the very small is asking if the object in question is physical Uncollapsed(stateless | unphysical) Quantum Waves + State(Matter Field or wave collapse) = Physical Matter Is a Matter Field state change the same thing as wave...

Hello! I know this is a very general question (and I am really a very beginner in the field) so I am sorry if it is dumb, but here it goes. In Schwarz book on QFT, at the end of Section 14.4 (path integrals chapter) he says: "We do not know if QED exists, or if scalar ##\phi^4## exists, or even...

I'm trying to understand the various different ways in which we can 'formulate' theories in physics and I am finding it somewhat hard to obtain a bird's-eye view. I hope someone here can help clear up some ambiguities. I apologize in advance for the 'sketchy' ways I put matters in my...

1/ Amongst what seems like the plethora of classical Unified Field Theories; that seemed to exist in the first half of the 20th century; see for example https://link.springer.com/article/10.12942/lrr-2014-5 [caution 50MB download] were they all abandoned just because of failure to account for...

Modern physics is comprised of a quartet of theory specializations. I. Classical Physics + Special Relativity S.R. II. Quantum Mechanics. QM III. Quantum Field Theory QFT IV. General Relativity GR Under what practical conditions do the predictions of each of these theories become...

The study of these theories is interesting in itself,if only to understand Godel's work. My question concerns their practical applicability to the solution of problems in different disciplines like mathematics, engineering, physics and the like. Are there reasons for studying them beyond the...

Looking for thorough serious comparative review of modern generalisations of classical non-equilibrium thermodynamics of continua. I have heard about several such generalisations: 1) rational mechanics by Truesdell, Coleman, Noll. 2) extended thermodynamics by Müller (and Ruggeri). 3) the...

In the quantum mechanics of covalent bonding, there are two competing theories: https://en.wikipedia.org/wiki/Covalent_bond#Comparison_of_VB_and_MO_theories Both are complementary, but they don't overlap fully, they still leave some gaps.What I want to ask is, can all the literature of the...

Some physicists, like Nima, Ed. Witten, Gross, and others have said/suggested that space-time is doomed, or emergent from something more fundamental. What ideas would replace space-time? Something similar to a perfect material? A fluid? Geometry? Quantum field theory of some sort? Entanglement...