Fields Definition and 1000 Threads

  1. S

    I Understanding Lorentz Transformation on Scalar Fields

    Hello! Can someone explain to me how does a scalar field changes under a Lorentz transformation? I found different notations in different places and I am a bit confused. Thank you!
  2. Math Amateur

    MHB Splitting Fields - Example 3 - D&F Section 13.4, pages 537 - 538

    I am reading Dummit and Foote, Chapter 13 - Field Theory. I am currently studying Section 13.4 : Splitting Fields and Algebraic Closures ... ... I need some help with an aspect of Example 3 of Section 13.4 ... ... Example 3 reads as follows: In the above text by Dummit and Foote, we read...
  3. Math Amateur

    I Splitting Fields - Example 3 - D&F Section 13.4, pages 537 -

    I am reading Dummit and Foote, Chapter 13 - Field Theory. I am currently studying Section 13.4 : Splitting Fields and Algebraic Closures ... ... I need some help with an aspect of Example 3 of Section 13.4 ... ... Example 3 reads as follows: In the above text by Dummit and Foote, we read...
  4. atommo

    Electron Spin and current-induced magnetic fields

    Hi, I'm currently investigating magnetic fields/their cause. This has inevitably led me to learn all about electrons. Here I want to post my understanding on electron 'spin' so people can correct me if I'm wrong/help others get a better understanding. So I watched this YouTube video for...
  5. B

    Jackson, Problem 5.2 (b); solenoid currents and fields

    Homework Statement Homework EquationsThe Attempt at a Solution These are problem 5.1 (b) and the solution. I understood the gap between each loop is 1/N, but why does each loop have vertical direction current amount of I/N ?? [/B]
  6. Mr Davis 97

    I Understanding Extension Fields & Polynomials

    I am a little confused about terminology when it comes to extension fields. In my textbook, E is a field extension of F if F is a subfield of E. This is understandable. However, in proving that all polynomials have a zero in an extension field, ##F[x] / \langle p(x) \rangle##, where ##p(x)## is...
  7. alv

    Charges in Magnetic Fields from Surfing Physics book

    I am a teacher and I can't work this one out. I am trying to answer (a). I have only included the further parts of the question (b, c and d) so you can see why some parts of the question are included. A single positively charged particle, mass 4.6 x 1027 kg, enters a 4.0 T magnetic field into...
  8. Math Amateur

    MHB Fields and Field Extensions - Dummit and Foote, Ch. 13 .... ....

    I am reading Dummit and Foote, Chapter 13 - Field Theory. I am currently studying Theorem 3 [pages 512 - 513] I need some help with an aspect the proof of Theorem 3 ... ... Theorem 3 on pages 512-513 reads as follows: In the above text from Dummit and Foote, we read the following: " ...
  9. Math Amateur

    I Fields and Field Extensions - Dummit and Foote, Ch. 13 .... .

    I am reading Dummit and Foote, Chapter 13 - Field Theory. I am currently studying Theorem 3 [pages 512 - 513] I need some help with an aspect the proof of Theorem 3 ... ... Theorem 3 on pages 512-513 reads as follows: In the above text from Dummit and Foote, we read the following: " ... ...
  10. F

    I Why are free-field Lagrangians quadratic in fields?

    What is the intuitive reasoning for requiring that a Lagrangian describing a free-field contains terms that are at most quadratic in the field? Is it simply because this ensures that the EOM for the field are linear and hence the solutions satisfy the superposition principle implying (at least...
  11. Math Amateur

    MHB Fields and Field Extensions - Lovett, Chapter 7 .... ....

    I am reading Abstract Algebra: Structures and Applications" by Stephen Lovett ... I am currently focused on Chapter 7: Field Extensions ... ... I need help with Example 7.1.5 ...Example 7.1.5 reads as follows: https://www.physicsforums.com/attachments/6572...
  12. Math Amateur

    I Fields and Field Extensions - Lovett, Chapter 7 .... ....

    I am reading Abstract Algebra: Structures and Applications" by Stephen Lovett ... I am currently focused on Chapter 7: Field Extensions ... ... I need help with the proof of, or at least some remarks concerning Example 7.1.5 ...Example 7.1.5 reads as follows: In the above text from Lovett...
  13. V

    A How do magnetic fields curve spacetime?

    According to the Einstein field equations, matter and energy both curve spacetime. I'm wondering how magnetic fields contribute to the curvature of spacetime. I have a few questions: 1. Does a magnetic field in a current-free region of a curved spacetime still satisfy Laplace's equation? Or is...
  14. B

    B Understanding Forces and Fields in Classical and Quantum Interactions

    Classically... interactions are referred to as forces, then after it is quantum(ized) or quantized, it becomes fields... so strong force becomes strong field, weak force becomes weak field, and electromagnetic force becomes electromagnetic field, gravitational force becomes gravitational field...
  15. N

    What do electric and magnetic fields look like around a dipole antenna?

    I am studying to about maxwell's equations on the electric and magnetic field. First of all, just do the example and exercise: https://www.princeton.edu/ssp/josep...ide-to-maxwells-equations-D.-FleischLEISC.pdf I have this dipole antenna...
  16. BluberryPi

    Other What fields of physics are there?

    I was looking into being a physicist (it sounds fun) and I discovered there were multiple fields. However my source was Wikipedia, and I need more information. What fields of physics are there? By field, I mean things like Astrophysics and Particle Physics.
  17. S

    Magnetic Fields- Finding the radius

    Homework Statement A single ionized uranium ion of mass 6.9 x 10 ^-25 kg is accelerated through a potential difference of 4.4 x 10^5 V. What is the radius of the path it would take if injected at 90 degrees into 0.47 T uniform magnetic field at this velocity? 3. Attempts Since centripetal...
  18. L

    Detecting Electric Fields with Motion: Is the Field Moving?

    Let's say I've got a charged particle moving with constant velocity and multiple columns of electric field sensors parallel to its path. The sensors will trigger whenever a maximum passes by. Will the sensors in a row be triggered at the same time? If they are, what does it mean for the field...
  19. Ian Baughman

    Other What are the upcoming growth areas in physics?

    I am curious as to what fields within the physics realm are going to be growing in the coming years. I am very interested in elementary particle physics but it seems to be a huge field with a lot of people already engaged in a wide variety of research under this topic. I also have an interest...
  20. F

    I Can Quantum Fields be derived from Particles?

    Typically, particles are said to be excitations of quantum fields. My question is whether fields can be derived from particles. Perhaps virtual particles can be summed up in some way to produce a field, for example. Any theories on this? Thanks.
  21. M

    I Constructing left invariant vector fields on SO(3)

    hello every one can one please construct for me left invariant vector field of so(3) rotational algebra using Euler angles ( coordinates ) by using the push-forward of left invariant vector field ? iv'e been searching for a method for over a month , but i did not find any well defined method...
  22. S

    Differential operator acting on scalar fields

    Homework Statement I really cannot seem to be able to follow the logic of how you would use the product rule when using 4 vector differential operator. ∂μ is the differential operator, Aμ is a scalar field and φ and φ* is it's complex conjugate scalar field. I have the answer, I'd just really...
  23. S

    A Gauge transformation of gauge fields in the adjoint representation

    In some Yang-Mills theory with gauge group ##G##, the gauge fields ##A_{\mu}^{a}## transform as $$A_{\mu}^{a} \to A_{\mu}^{a} \pm \partial_{\mu}\theta^{a} \pm f^{abc}A_{\mu}^{b}\theta^{c}$$ $$A_{\mu}^{a} \to A_{\mu}^{a} \pm...
  24. G

    Magnetic fields and moving electrons

    Hi forum, I have been thinking about the circular magnetic field pattern around a long straight current carrying wire and wondering about what the field pattern would be around an isolated electron moving straight in a vacuum? Somehow the magnetic field of all the individual electrons moving in...
  25. J

    I If an electron isn't fundamental, what fields are it made of

    http://www.nature.com/news/not-quite-so-elementary-my-dear-electron-1.10471 It was found out that electrons are made of quasi particles. But kind of fields are the quasiparticles made of?
  26. Frippertronica

    Job Skills Fields of Physics I'm Most Likely Able to Do Research In?

    First, a bit of background. I am currently in a Master's program, studying specifically particle physics and astrophysics. I've always wanted to do research in astrophysics, even from my first day as an undergrad. I've thought about doing research in other fields, but I've never really given it...
  27. W

    A question on E Flux and Fields

    Homework Statement 1. The field for an infinite charged sheet is found to be σ/2ε0. If we place 2 infinite sheets of opposite charge above one another, we say that the field in between the sheets is σ/ε0 due to the superposition of individual fields. Why can't we say the same for a situation...
  28. P

    Finding the Direction of Magnetic Fields with Opposing Currents

    Homework Statement How do I find the direction of the magnetic field at the points? Homework Equations Ampere's B = (UI) / (2*pi*r)[/B]The Attempt at a Solution I know how the Right hand rule, where your thumb is the direction of the current and your hand wraps the direction of the field...
  29. Azura

    About electric fields (Symmetry)

    1) Imagine you have a clock but in each number you have a charge "q". If I have a test charge Q at the center, then by simetry, the net force on Q is zero. I imagined like, 1 cancels 7, 2 cancels 8, etc... But then, if I have a polygon with 13 sides, with a test charge Q, the net force also...
  30. S

    Electric currents and Magnetic fields

    Homework Statement A Neutral copper Rod, a polarized insulator rod, and a bar magnet are arranged around a current-carrying wire. Will the neutral copper rod, polarized insulator, and magnet remain stationary?Homework Equations does the electric field of the current carrying wire have an...
  31. CricK0es

    Applications of the Helmholtz Coil: Shielding and Stabilizing Fields

    Homework Statement Hi, I've got a presentation on an experiment we did using the Helmholtz coil and I'm starting to run dry on material. As some additional applications I found that you can: - Use the coil set up to cancel external interference (Shield other experiments? Not sure about that...
  32. D

    I Fields: Unobservable, Yet Physical?

    I'm currently working through Robert Klauber's Student Friendly Quantum Field Theory, which by the way is much more accessible than other texts like, say, Peskin and Schroeder, for others also coming into QFT via the self-study path. Anyhow, he mentioned something that never really clicked...
  33. M

    I Lie groups left invariant vector fields

    hello every one . can someone please find the left invariant vector fields or the generator of SO(2) using Dr. Frederic P. Schuller method ( push-forward,composition of maps and other stuff) Dr Frederic found the left invariant vector fields of SL(2,C) and then translated them to the identity...
  34. T

    Metal: no attraction to magnet and block magnetic fields?

    Hi, Can anyone help me in finding out a Diamagnetic or Paramagnetism or Ferromagnetism or any other metal which has following capabilities: 1- Should not be attractive towards magnet. 2- Should not allow magnetic fields to pass through inside. Thanks! THG
  35. G

    Identities of fields in Maxwell's equations

    Hello. I would like to ask one simple question. Do we need to distinguish E-field (Electric field) in Gauss's law from those in Maxwell-Faraday equation and Ampere's circuit law? I firstly thought that E-field in Gauss's law is only for electrostatics so I need to distinguish it from E-field in...
  36. S

    Moving charges and varying magnetic fields

    I understand that a steady flow of current will not induce currents in near by conductors. But, what about a steady flow of current that is being accelerated perpendicularly by a uniform magnetic field? Wouldn't this current produce a time varying magnetic field? This is a conductive disk with...
  37. R

    Electric Fields Question, What is the speed of the electron?

    Homework Statement An electron is released from rest in a weak electric field given by -2.8 x 10^-10 N/C [PLAIN]https://www.flipitphysics.com/Content/smartPhysics/Media/Images/Tipler/Symbols/jhatbold.gif. After the electron has traveled a vertical distance of 1.9 µm, what is its speed? (Do not...
  38. P

    Derive the wave equation for fields E, B from the potentials

    I'm studying for my electrodynamics exam and one of the past exam questions is: From the scalar and vector potentials, derive the homogenous wave equations for E and B fields in vacuum. I did derive the wave equation for the B field by simply taking the curl of the homogenous wave equation for...
  39. N

    Programs Switching Fields: Should I finish the major or just switch?

    I'm a sophomore math and physics double major, and I'm losing interest in physics. I still love math (like seriously love), but I honestly don't see myself working in a physics lab or anything. A lot of the modern physics stuff really does not appeal to me at all. I currently plan on switching...
  40. M

    B Are All Quantum Gravity Theories Based on Covariant Quantum Fields?

    I just read Carlo Rovelli new book "Reality is Not What It Seems: The Journey to Quantum Gravity" in one sitting. I'd like to know about the following: "Fields that live on themselves, without the need of a spacetime to serve as a substratum, as a support, and which are capable by themselves of...
  41. jedishrfu

    B Exploring the Fields of Physics with Dominic Walliman

    Another great video from Dominic Walliman mapping out the fields of Physics:
  42. jedishrfu

    B The Fields of Mathematics Video

    Dominic Walliman's video summarizes the various fields of maathematics in a wonderfully short video: http://sploid.gizmodo.com/take-a-quick-tour-of-the-mind-boggling-universe-of-math-1792041367
  43. PsychonautQQ

    I Are Splitting Fields Unique for Different Polynomial Families?

    So if E and E' are both extensions of K so that both E and E' are splitting fields of different families of polynomials in K[x], then E and E' are not isomorphic, correct? They need to be splitting fields for the same family of polynomials in K[x], correct?
  44. JulienB

    Relativistic E and B fields of an infinitely long wire

    Homework Statement Hi everybody! I have the following problem to solve: An infinitely long and thin straight wire carries a constant charge density ##\lambda## and moves at a constant relativistic speed ##\vec{v}## perpendicularly (##\beta##) and parallel (##\alpha##) to its axis. a)...
  45. W

    Understanding Electric Fields and Flux in Charged Objects

    Homework Statement Not so much of homework questions but more to do with clarifying concepts: 1. How do i assess whether or not field lines emitted by charged objects (i.e uniformly charged cube) are both perpendicular to their surfaces uniform? This is in relation to taking the E of ∮φ = EdA...
  46. mpolo

    Experimental investigation of c in electric & magnetic fields

    I have been researching a question I have concerning the speed of light in magnetic AND electric fields. I came across an article in arvix but could not quite understand what they were saying. I am not a scientist I am just curious. There was a statement in which was shrouded in a strange...
  47. Q

    Unruh Effect for Standard Model Fields

    I have seen the derivation for Unruh radiation for a massless, non-interacting scalar field (Carroll). Are there interesting differences that arise for more realistic standard model cases. For example, what does QCD look like for an accelerating observer? Any papers that detail this would be...
  48. E

    I Why can't atoms accept energy from static electric fields?

    Though I am definitely not an expert in any way in QM, I understand that on a basic level quantum systems can be solved using schrodinger's equation. For a hydrogen atom, the wave function of the electron is found by using the hydrogen proton as an external potential and proceeding from there...
  49. hilbert2

    A Spectral intensities from E&M fields

    A question about the relation of light intensities to the actual time-dependent EM field: Suppose I have a system where the functions ##\mathbb{E}(\mathbf{r},t)## and ##\mathbb{B}(\mathbf{r},t)## (time and position dependent electric and magnetic fields) are known. I would like to have an...
  50. E

    Maxwell's/Faraday Law Concern Propagation of Induced Fields

    The integral form of Maxwell's equation pertaining to induced electric fields is: ∮E(t0)⋅dℓ= −dΦ(t)/dt|t=t0Say for a long time, in some circular region there has been no B or E fields present. Then, there is a sudden constant increase of B field introduced in the middle. I know that information...
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