Weak Definition and 503 Threads

In mathematics, weak topology is an alternative term for certain initial topologies, often on topological vector spaces or spaces of linear operators, for instance on a Hilbert space. The term is most commonly used for the initial topology of a topological vector space (such as a normed vector space) with respect to its continuous dual. The remainder of this article will deal with this case, which is one of the concepts of functional analysis.
One may call subsets of a topological vector space weakly closed (respectively, weakly compact, etc.) if they are closed (respectively, compact, etc.) with respect to the weak topology. Likewise, functions are sometimes called weakly continuous (respectively, weakly differentiable, weakly analytic, etc.) if they are continuous (respectively, differentiable, analytic, etc.) with respect to the weak topology.

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  1. tom.stoer

    Z° Isospin: Understanding T³=0 and Weak Isospin in Particle Physics

    Z° and weak isopsin The Z° is a mixture of the B (iso-scalar) and the W° (iso-triplet with T³=0). Is it OK to say that the Z° still has T³=0? Or is this meaningless due to the breaking of the original SUwI(2) * UY(1) to Uem(1) and the mixing in the Z°?
  2. dextercioby

    What Is an Example of Weak but Not Strong Convergence in L²(R)?

    So I've seen the distinction one makes in case of infinite-dimensional Hilbert spaces. Weak convergence versus strong convergence of sequences. I cannot think of an example of sequence of vectors in L^2(R) which converges with respect to the scalar product, but not with respect to the norm...
  3. G

    What Volume of Ethanoic Acid is Needed to Neutralize 25ml of 0.1 M NaOH?

    Hi, I came across a problem, which I might have solved a few years ago when I had studied Chemistry, but now I am totally stumped. Would appreciate some quick solutions. I have 25 ml of 0.1 M NaOH, and a volume of 0.1 M of Ethanoic Acid. What volume of ethanoic acid would neutralize the 25...
  4. S

    Weak Acid - Strong Base titration. Too little information?

    Homework Statement In order to achieve a high result in this chemistry assignment, I need to have demonstrated a knowledge of challenging content not discussed in class. Every other part of this assignment I've covered (Intro, method, discussion etc), I am just stuck with the calculations...
  5. TrickyDicky

    Weak equivalence principle and GR

    In another thread, it's considered a generally accepted fact that the WEP is not valid anymore the way it was initially postulated: I find this surprising, because such a change in the principles of the theory should be more stressed in introductory GR textbooks, and kind of disturbing...
  6. D

    Finding Range of Weak Interaction from Mass of Z Boson

    Homework Statement One of the mediators of the weak interactions is the Z boson, which has a mass of 91 GeV/c 2. Use this information to find an approximate value for the range of the weak interaction. Homework Equations This is the part that I am having trouble with. I don't know where to...
  7. M

    Parity Violation of Weak Force - Wu et al.

    I have read about Wu et al. and their experiments with Co 60 that showed that the weak interaction violates parity. I don't quite get it tho. 6 So they aligned Co atoms in a magnetic field. Some of the nuclei decay and emit neutrinos and electrons. It was observed that an equal number of the...
  8. Simfish

    How exactly does the pion decay through the weak force?

    So the pion(+)n is made up of an up quark and a down antiquark. And somehow, it emits a W+ boson, which then turns into a muon and a muon-neutrino. From the Wiki article, "W bosons can decay to a lepton and neutrino or to an up-type quark and a down-type quark." Does this mean that the...
  9. A

    How to Determine the Dissociation Constant of Ethanoic Acid?

    I'm preparing for a chemistry lab relating to "Determination of the dissociation constant of a eak acid". In part of the lab, I will b doing the following for measuring "Ka" for ethanoic acid using the indicator method: 1- Mix ethanoic acid (0.02M, 5cm3) and sodium ethanoate (0.02M, 5cm3)...
  10. M

    Euler Lagrange equation - weak solutions?

    Hello there, I was wondering if anybody could indicate me a reference with regards to the following problem. In general, the Euler - Lagrange equation can be used to find a necessary condition for a smooth function to be a minimizer. Can the Euler - Lagrange approach be enriched to cover...
  11. T

    'Mass' of an object at different positions in a weak gravitational field

    We had a physics lesson today on nuclear binding energy, where we looked at the mass of two protons and two neutrons independently and compared it with the mass of a helium nuclei, and were told how the discrepancy related to the release of energy during nuclear fusion. The first question in...
  12. C

    Why is the Chin Considered a Weak Spot in Hand-to-Hand Combat?

    Hello, Chitose here while I'm learn about hand in hand combat, someone told me that to always protect my chin. "No matter how strong, big or well train people are, getting direct hit at chin will take him down instantly" in boxing, both fighter are also protect and try to hit each other...
  13. J

    A couple of questions about the weak force.

    Is the weak force responsible for all radioactive decay, or just beta? If it is also responsible for alpha and gamma, how does it work? If not, what causes the other two? (Also, related to this, I know that alpha radiation is two protons and two neutrons being expelled from the nucleus, and...
  14. WannabeNewton

    Question on weak field approximation

    In A First Course in General Relativity, the use of the weak field approximation is confusing to me. I constantly get confused when the term "f(x) is only valid to first order in f..." for the Newtonian potential in the metric comes up. At a certain point the book states: ...1/2(-1/(1 +...
  15. L

    Reissner- Nordstrom metric- weak energy condition

    Hey, For a problem I am working on I need to know if the energy-momentum tensor of the Reissner- Nordstrom metric obeys the weak energy condition. Since I need the result for the following calculations, I just want to be sure that it is correct. Does anyone of you know the correct answer and...
  16. N

    How to find the ph in a strong base weak acid titration?

    Homework Statement If .0200L of .100M nitrous acid is titrated using .200M NaOH solution, what will the pH be at equivalence? Homework Equations The Attempt at a Solution I figured out that the volume of NaOH at equivalence is .01L, however I do not know what to do after that...
  17. B

    Electromagnetic and the weak force

    Homework Statement I need an example of the math Homework Equations The Attempt at a Solution
  18. C

    Are Amines Considered Strong or Weak Acids and Bases in Mastering Chemistry?

    So, it's for Mastering Chemistry and I need to sort out the strong acids weak acids strong bases and weak bases. It says that two are wrong though I've looked them all up and don't know which ones are wrong. [PLAIN]http://bit.ly/fREfFS
  19. H

    Neutron Decay and the Weak Force

    I believe the neutron decays with a half life around 12 minutes via the weak mechanism. I'm wondering what causes a particular neutron to decay. At the moment the neutron decays, has it encountered (run into) a stray weak field? Or ... does the neutron decay just because of internal forces...
  20. Z

    Probability - A and B are two weak students

    Probability - A and B are two weak students... Homework Statement A and b are two weak students in Mathematics. The chances of their solving a problem correctly is 1/8 and 1/12. The probability of them making a common mistake is 1/1001 and they obtain the same answer. Find the chance that...
  21. M

    Where does the energy of a destroyed W boson go?

    Hello. I'm new so I am uncertain to which forum this post should be posted in so I'll just leave this here. Anyways, I was reading about the four fundamental forces and it came to my mind that the W boson is 80.4 GeV, whilst the two lepton that are excreted upon destruction are 0.511 MeV...
  22. E

    Where Can I Find Rigorous Solutions for Weak Acid-Weak Base Equilibria?

    Such an equilibrium problem involves 3 equilibria: a weak acid, a weak base, and water autoionization. I find in various texts that several assumptions are made in dealing with this class of equilibria problems (ignore water's autoionization, conversion of the weak acid is on the order of...
  23. I

    Velocity of an electron within a weak electric field?

    This is the question: "An electron is released from rest in a weak electric field given by vector E = -1.80 10-10 N/C jhat. After the electron has traveled a vertical distance of 1.2 µm, what is its speed? (Do not neglect the gravitational force on the electron.)" So far, the only approach...
  24. R

    Strong and weak interactions in nuclear physics

    Homework Statement How do we determine whether we have a strong or a weak interaction? (for the following processes) For example we have a reaction K^{-}+p\Rightarrow \Xi^{-}+K^{+} or another example K^{+}\Rightarrow \pi^{+}+\pi^{0} thanks!
  25. N

    Does the strong force affect the weak force

    Hello, can anyone help. Does the strong force affect the weak force in any way. Or do both not interact with each other. Thank you.
  26. S

    Calculating pH of a solution with two weak acids and a strong base

    Homework Statement 0.5332 M CH3COOH 0.1219 M CH3COONa 0.100 M H2S 0.41452 M NaOH what is the pH of the resulting solution? Homework Equations CH3COOH Ka=1.75E-5 H2S Ka1=9.6E-8, Ka2=1.3e-14 The Attempt at a Solution I know that neutralisation will occur, but there is not...
  27. P

    Unraveling Weak Field Stark Effect in Hydrogen

    Homework Statement Considering the n = 2 states of hydrogen: In the absense of an external field, the four j = 1/2 states are degenerate. Using degenerate pertubation theory, I am supposed to show that for a very weak field the Stark effect shifts the energy levels by \mp \sqrt{3}a_0 e...
  28. E

    Running coupling of the weak interactions

    Can someone point me to a reference that explains how the (effective) running coupling behaves in the weak interactions(at 1-loop order). I couldn't find it... If I understand correctly, than the coupling is g = \frac{e}{sin(\theta_W)} where e is the QED coupling, which increases with energy...
  29. S

    Weak & Strong Magnet attract each other no matter what polarity

    Recently while working with electromagnet , we noticed one thing. I we bring strong magnet near very weak PM or electromagnet, It will attract the weak one whatever is the polarity of magnets. we increased power to electromagnet then it was giving repulsion. I did't understand this...
  30. R

    Feynman diagram for weak interaction.

    For a leptonic weak interaction diagram, we have an election converted into a neutino and emitting a w- particle. But only left handed part should undergo weak interaction. So basically you should have the left handed part of electron converted into a neutrino(left handed) emitting a w-...
  31. J

    Can particles be weak force charge neutral?

    can particles be "weak force" charge neutral? In the standard model we have fermions of various electrical charges, including neutral. In some sense, we can consider right handed electrons as "weak force" neutral, however the mass term kind of "mixes" the left and right handed. Is there...
  32. K

    Exploring Weak Interactions: Gravitational, Electrodynamics, Nuclear, and Quarks

    Gravitational force between masses is given by the law of universal gravitation. Electrodynamics force between electric charges is the Lorentz force. Nuclear force between nucleons falls off exponentially with rising the distance. The force between quarks grows in proportion to the distance. Can...
  33. S

    Weak Electron Interaction: Virtual Photon Effects?

    hi, let's suppose 2 electrons are far away each other and therefore they interact very weakly. i wonder if in such case there are as many virtual photons in the case they are very close to each other? because i know that only 1 electron in complete vacuum generates an electromagnetic field and...
  34. G

    Weak force holds neutrons together?

    I have been given the impression that the weak force is what holds the neutron together (preventing it from decaying to an electron and proton) and that the neutron eventually decayed, despite this weak force, by 'tunneling out' Is that right or am I way off?
  35. L

    How Does the Buffering Action of Weak Acids Change During Titration?

    Homework Statement I'm a little confused, let's say i do a titration curve for a weak acid, at some point there's a buffering range near the pKa. Like i know that if we add a strong base like NaOH to acetic acid in a water solvent, then the OH- will combine with the H+ (hydronium ion) which...
  36. 1

    How to calculate pH of two weak acids

    how to calculate the pH of a mixed solution containg 0.200M HA and 0.2 HB ka of HA =1.0^10-5 KA OF HB = 1.0^-6
  37. I

    Intuitive Difference Between Weak And Strong Convergence in Probability

    I've seen numerous rigourous/conceptual explanations of the difference between convergence in probability (weak), and strong, almost sure convergence. One explanation my prof gave was that convergence in probability entails: \lim_{n \rightarrow \infty}...
  38. L

    What happens when a strong base is added to a weak acid?

    Homework Statement In my textbook, they don't necessarily explain what happens when we add a base to a weak acid (e.g. acetic acid)...so I was wondering if anyone can tell me if I got it down: -Like if we have acetic acid (which is a weak base) in water, it will form an equilibrium and...
  39. michael879

    Conservation of weak hypercharge and isospin

    So I've been playing around with different electroweak lagrangians (sourceless, higgsless, unbroken, broken, etc), and finding the equations of motion for them. Everything looks about right, but the issue I'm having is when you add in the masses of the weak bosons(no higgs though).This breaks...
  40. S

    Purpose of the weak nuclear force?

    Can someone explain in layman terms the purpose/function of the weak nuclear force?
  41. F

    A massive force carrying particle? The weak nuclear force, the W boson has mass?

    I was looking at the list of the force carrying particles and all of their masses read zero other than the W boson of the weak nuclear force. Q: Does the W boson travel at the speed of light even if it is massive? (I am guessing not) Q: If the W boson is massive then it emits other gauge...
  42. Z

    How Does Chirality Affect Weak Decay Cross Sections?

    Weak decay -- cross sections I have to estimate the ratio between the cross sections of the following weak processes: \nu_{\mu} + e^{-} \Rightarrow \nu_{e} + \mu^{-} \bar{\nu_{e}} + e^{-} \Rightarrow \bar{\nu_{\mu}} + \mu^{-} My teacher says that as the first process is LL \Rightarrow LL...
  43. J

    If Higgs-matter interaction is weak, can it be altered?

    I have heard that the coupling between Higgs to matter is weak, that it is a correspondingly weak effect. If this is true, is there any way that that effect can be made weaker or stronger? Or asked another way, what is it that sets the magnitude of the level of effect? Thanks
  44. C

    Investigating Weak Gravitational Field in India/Indian Ocean

    Anyone know what causes the weak gravitation field at the bottom of India / Indian Ocean (see link below)? Thanks http://news.bbc.co.uk/2/hi/science/nature/8767763.stm
  45. MathematicalPhysicist

    Question regarding CP symmetry and weak interaction

    I have the next decay: B^0 \rightarrow D^+ e^- \nu_e The question is: employ CP symmetry on the particles in this process, what reaction would you get? and what would happen if CP symmetry breaks? Now if I employ CP symmetry I get: B^0 \rightarrow D^- e^+ \bar{\nu_e} But in my...
  46. K

    Electroweak Interaction: Theory & Symmetry

    I understand that the Colour Force is described by Quantum Chromodynamics, Electromagnetism is described by Quantum Electrodynamics and Gravity will hopefully be described by a Quantum Gravity Theory but currently General Relativity. But what Theory describes the Electroweak Interaction? Is...
  47. humanino

    What Are the Experimental Constraints on the Running of the Weak Coupling?

    Dear all, would anybody know of references regarding experimental constraints on the running of the weak coupling ? This running is rather slow, and I guess we do not have evidence one way or the other, but since the SM and the MSSM have opposite slopes, I'd like to see what kind of...
  48. I

    The weak force and effective coupling

    I just read something about the creation of deuteron in the first step of the pp cycle. Given that you have the reaction: p + p -> d + e^+ + v_e, where e^+ is a positron and v_e is an electron neutrino. Since there is a neutrino present, it is a weak interaction. In addition, as the interaction...
  49. B

    K+ Decay: Is the Feynman Diagram I Drew Correct?

    I've attached a feynman diagram i drew myself because i can't find a proper feyman diagram for this decay. I assume that since the decay K+->u+ + Vu is weak it goes via a W boson. Is this diagram correct? thanks
  50. B

    Particle Spin, Isospin, weak Isospin

    I'm losing my mind trying to differentiate spin, isospin, weak isospin; then there's chirality, helicity - i must be dyslexic and quantumly challenged. Since it would be a monumental undetaking to do this online, does anyone know of a reliable source i can access online (other than wikipedia...
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