Theories Definition and 486 Threads

  1. Z

    Can stars predict the future of our world and universe?

    I have been wondering lately is it possible to predict happenings in world and universe by the position of the stars,and if so how? :confused: Please help thanks:smile:
  2. T

    Why do we use Gauge Theories to describe local conservation of charge?

    Once I've asked here why you physicist use Gauge theories with such confidence and the overall answer was "because it works". This probably is true but perhaps is also a bit disappointing to me because I was looking something more fundamental. I've recently thought of something that may be the...
  3. R

    Exploring Physical Theories of Interdimensional Travel

    I'm wondering if their are any unified physical theories that predict our universe to be a part of a multiverse in our own dimension? I'm looking for anything along the lines of stating that our universe is a star in a 'galaxy' of other universes that we can theoretically travel to if we could...
  4. H

    Acid Base Theories: Bronsted-Lowry vs Lewis

    what theories out of the major two ( Bronsted-Lowry Theory of acids and bases and The Lewis Theory of acids and bases) should we use in common problems, and which one is more reliable ?
  5. N

    Text book for SU5/GUT theories

    Dear PF, Could you please advise me good detailed reference on Grand Unified Theories... especially I want to see where for example SU5 potential is composed from two Higgs representations (two Higgs fields) and how symmetry breaking (minima of potential appears for both of fields) happens...
  6. L

    Physics Theories of Stage Lighting?

    For my physics class, we are doing a large project for our finals. I wanted to do mine on dealing with stage lighting (theatre). I tried googling and doing some research, but couldn't find much. Does anyone know any theories related to the physics of stage lighting?
  7. T

    Is Impulse a Discrete Observable in Physics? Exploring Possible Models

    Hi there, I have a short thought that I want to share with all of you and see if there has been something written about it and, if not, why not?: A free particle spin is something that can take a discrete range of values, as it happens with electromagnetic or colour charge. However the other...
  8. james.goetz

    Do theories of quantum gravity require that space-time is a lattice?

    Do theories of quantum gravity require that space-time is a lattice instead of a continuum? I guess this question has been addressed elsewhere, but I would appreciate hearing different points of view. Please dummy down the responses so a philosopher can understand it.
  9. I_am_learning

    Exploring Theories of Humour: Benign Violation & Industry Standard

    Out of all the theories, I find the "Benign Violation Theory" to be most promising. Lets see if somebody got some counter examples? Also, what's the Industry Standard Theory, if there is any such thing. ? http://en.wikipedia.org/wiki/Theories_of_humor P.S. Philosophy forum seems too tough...
  10. I_am_learning

    Theories of Laughter: Benign Violation & Industry Standard

    Out of all the theories, I find the "Benign Violation Theory" to be most promising. Lets see if somebody got some counter examples? Also, what's the Industry Standard Theory, if there is any such thing. ? http://en.wikipedia.org/wiki/Theories_of_humor
  11. J

    Non-diff theories of dynamical spacetime

    Is it possible to formulate a dynamical theory of spacetime geometry that isn't invariant under active diffeomorphisms? Or does requiring no invariance under active diffeomorphisms restore of gravity as a force? If yes, then it makes it difficult to disentangle the issue of active...
  12. I

    Help, looking for a philosophy book about theories of everything

    Hello all, I am currently trying in vain to find a book that i do not know the name of. I heard it mentioned somewhere that I can not recall so now am lost. Basically it is a book with (I think 50) interesting theories about everything. Like string theory parallel universes etc. Has anyone heard...
  13. D

    What are the Main Theories for the Current State and Structure of the Universe?

    Hi, I'm wondering what the main theories for the state/structure of the universe are and what they consist of? Not the creation but the current state/structure of it.
  14. J

    Theories on Series and Parallel capacitors

    Homework Statement 1.When three different capacitors are connected in parallel as in figure 2 in the lab manual: (Choose all relevant answers below) 2.When three different capacitors are connected in series as in figure 1 in the lab manual: (Choose all relevant answers below) a. The...
  15. J

    Theories on Series and Parallel Resistors

    Homework Statement 1. When three different resistors are connected in parallel to a battery whose voltage output is V as in figure 2 in the lab manual: (Choose all relevant answers below) 2. When three different resistors are connected in series with a battery whose voltage output is V...
  16. T

    Path Integral/Canonical Quantization of Gauge Theories

    I'm really getting frustrated right now, as I am unable to reproduce the two-point gauge-field correlation function (i.e. propagator) as derived from the path integral in an R_\xi gauge using operators from canonical quantization. I believe the polarization 4-vectors of the gauge field ought to...
  17. M

    Relativity vs competing theories

    hey guys, I'm just wondering about the existing competing theories; it's been mentioned in a number of threads that there are a couple of theories which equally explain the results of relativity experiments, but which are based on different underlying principles. I've also read that...
  18. M

    Gauge Theories in Particle Physics: Questions Answered

    i'm reading 'gauge theories in particle physics' by aitchison (http://www.ft.uam.es/personal/hernandez/QFT/Aitchison--Gauge-Theories-in-Particle-Physics-Volume-1.pdf) and i have some questions: 1. middle of page 23 right before section 1.2.3 heading: he implies because of the spectroscopy...
  19. T

    Why should we work with gauge theories

    1) In one thread I saw that a Lagrangian that comes from a gauge theory principle is capable to generate interactions, and that would be why we should work with gauge theories. Nevertheless, any lagrangian which have multiplications of diferent fields generates interactions (or am I wrong?) 2)...
  20. F

    How Do Garrett Lisi's Theories Challenge Current Physics Paradigms?

    Garrett Lisi, the skill level of physicists, & multiverse/holographic theories Okay, so after 2 times of firefox crashing and me loosing my whole 1 hour long versions of my topic (2 hours wasted fyi lol) here it is in the express version. Two questions. Both have to do with Garrett Lisi...
  21. C

    Thevenin and Norton Theories help

    the problem presents a wheatstone bridge design, with a 10 V DC power supply. R1 is 2 ohms, R2 is 3, Rx (presented as R4 for this problem) is 4, the typical 'bridge' portion is replaced with a 1 ohm resistor (labeled R3), and where you usually have R3 you have a load, which is 5 ohms. The...
  22. Islam Hassan

    Theories for Mechanisms Underlying SR/GR?

    If I understand correctly, SR & GR describe with accuracy (ultra-relativistic) motion, acceleration and gravity but do not explain the underlying mechanisms that may be causing it. What is the present state of theorising regarding the mechanisms which may underly SR/GR? To take the speed...
  23. S

    Need help with Theories of Everything in 21st century

    I need to construct a timeline for the quest for the theory of everything from the 20th-21st century. I need help. I'm having trouble with the 21st century part since there aren't much books on this. Can anybody please inform me of all the TOE in the 21st century and what their up to? For...
  24. B

    Experiments that try to contradict theories (but proved them)

    Hey, I'm looking for examples of Experiments by physicists who tried to prove a theory wrong, but ended up with results that agree with theory. I'm not talking about experiments that were done on a widely accepted theory. for example, Robert Milikan's experiment of the photoelectric...
  25. J

    How to react when students doubt the validity of scientific theories

    I encourage my students to participate in class and think for themselves. I often get questions or remarks about concepts that I teach that stem either from a misunderstanding of an idea, or lack of clarity as to the evidence in support of a theory. I usually find these to be helpful in...
  26. W

    Questions that deal with research, strategies, math and theories

    I read that theories are a framework of explanations of experimental data and that they predict experimental results. I have also read that sometimes data comes before there is a theoretical explanation and vice versa; theoretical explanations predict data that has not been yet proven by...
  27. X

    Correlation between problem solving skills and being able to derive theories.

    From my understanding the job of a theoretical physicist is to derive theories to explain phenomena in nature. But let's say you aren't the best problem solver in the world. You are good enough in your physics class to get the 3.5 GPA but you are never able to solve those extra credit problems...
  28. R

    Black holes, dark matter, the expansion of the universe, and unifying theories.

    A thought experiment I have been thinking about this for twenty years and I would like to hear your opinions. It relates to black holes, dark matter, the expansion of the universe, and unifying theories. This is very simple and beautiful to me. Forgive my lack of formal training, my goal...
  29. F

    Why can we never be certain of our scientific theories?

    Why can we never be certain of our scientific theories? The reason i love mathematics and physics is that the rigorous knowledge they impart about reality or what lies beneath it. Yet the more physics I study, the more I realizes how very little we know. What is gravity? what is force? What is...
  30. L

    Chrial gauge theories and anomalies(Srednicki ch75-76)

    Hi, Don't know if anyone can help me but have a bit of confusion with Srednicki ch75 p466 just above (75.55). I understand why in non-Abelian gauge theory we get extra factors Tr(T^aT^bT^c) and so on, but I don't understand why the P_{L}\to1/2 diagrams then end up with the extra factor...
  31. bohm2

    Albert's narrative argument against Everett-type theories

    I hope this didn't come up and I'm not just repeating it but I did a search and couldn't find anything on it. So, how convincing do others find Albert’s narrative argument against the advantages of Everett-type theories: If all this is right, then many-worlds and many-minds and...
  32. phinds

    Dwarf galaxies suggest dark matter theories may be wrong

    I realize BBC science news is not a totally reliable source, but I'm wondering if any of the knowledgeable folks here have any comment on this: http://www.bbc.co.uk/news/science-environment-14948730 I tried to find if there had already been a thread on it, but I may have not looked hard...
  33. A

    Post-measurement states in generalized probabilistic theories

    Hello everybody I am currently trying to understand attempts to create a framework of generalized probabilistic theories in which quantum theory and classical theory appear as special cases. More precisely, I try to understand the framework which is sometimes called the framework of "convex...
  34. B

    Are our theories or are observations more advanced?

    Hi all, I was just watching an old Feynman clip. In it, he describes areas where our observations are ahead of our theories (e.g. quasars) as well as areas where our theories are ahead of our observations (e.g. black holes). http://www.youtube.com/watch?v=6OrsaL97Epg&feature=related I...
  35. chaszz

    Cuurent statuses of theories of gravity

    I know that Newton's theory of gravity fails to predict certain features of Mercury's orbit in comparison with GR, and also fails to predict the bending of spacetime around a star shown by the path of light. And perhaps one or two other failures which I forget. But I've read that Newton's laws...
  36. C

    About some possible theories of the creation of the universe?

    Hello, I have an Idea that i would like you guys to examine and tell me if it is good or not. Since people do not yet fully understand a black hole, and supposedly predicted my Hawking that a black hole can disappear out of nothing and that the information can't be lost, or just vanish into...
  37. M

    Classification of Gauge Theories

    Hi there: I was just searching about Gauge theories and stuff and I find it very confusing. My major complication is the classification. I'd like you to tell me some definitions and construct a "family tree". I guess it goes something like this: Gauge Theory: A Field Theory in which the...
  38. M

    Kaluza-Klein theories in twelve dimensions and F-theory

    "Kaluza-Klein theories in twelve dimensions" ... and F-theory This is a separate thread to discuss another idea by arivero, originally https://www.physicsforums.com/showthread.php?t=485247&page=4#63". Some references: http://www.sciencedirect.com/science/article/pii/0550321385902329" )...
  39. M

    A query on the (old) motivation for renormalizable theories

    I've just realized I don't understand something pretty fundamental about the need to renormalize. Popular wisdom has it (or had it - forget the shift towards an effective framework) that theories that were not renormalizable had no predictive power, on account of the fact each n-point vertex...
  40. Spinnor

    Could hidden dimensions help hidden variable theories ?

    Could hidden dimensions help "hidden variable theories"? Could extra unobserved dimensions be of use in finding a hidden variable type theory that also satisfied Quantum Theory? Thanks for any help!
  41. E

    Theories on Dimensions/Time Quantized?

    I wasn't sure what category to put this in or if the proceeding questions are established theory so I decided to put it in "Beyond the Standard Model." Is there evidence to suggest that a length can only be so small or that all lengths are infinitely divisible? Is there evidence to suggest...
  42. W

    Light Bending: Comparison of Theories

    In the essay „Über die Ablenkung des Lichtes I am Schwere*feld der Sonne“ ( http://adsabs.harvard.edu/full/1931ZA...3..171F ) the authors - Freundlich, Klüber and Brunn - presented 1931 graphically the results of three expeditions, which took place 1919, 1922 and 1929. They put together all...
  43. T

    Are there any theories that explain where matter and energy came from?

    Like has anyone ever said a reason to how matter and energy came into existence?
  44. wolram

    The bounce and many universe theories

    In some theories the universe ends/starts with a bounce, is this true with the many universe theory, ie all universes bounce at the same time. this has had me thinking for some time as ,AFAIK there is nothing to say that alternate universes start and end at the same time. In other words some...
  45. S

    Problem of time: No-time theories?

    Hi there PF :) Are there currently any physical theories trying to get rid of time, since time is not actually a measureable quantity (one measures the frequency of a quartz crystal in a wristwatch, not time, one measures the frequency of a pendulum in a tower clock, not time, one measure...
  46. J

    Exploring Gravity: Other Theories in Modern Physics

    Is there any other formally considered theories relating to the operations of gravity other than relativity? They must still be considered in modern physics. If so could one point me in the direction.
  47. K

    Quantum Gravity Theories: What is UV Complete?

    What theories of quantum gravity are currently UV complete?
  48. A

    Theories predicting electron mass

    Electron mass is a debated topic, and i was just asking if anyone could suggest a few theories about the electron mass and perhaps i could try and derive my own. Thanks alot!
  49. K

    Time Theories: Outta Universe, Relativity, Multiverse

    how does one define time? iv we viewed time from outta our universe...would einsteins theories of relativity still hold...i mean would any of the laws of physics in our universe hold if we assumed the multiverse model of the universe(s)?
Back
Top