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  1. Q

    Commutator in QM vs. Lie brackets in DG

    the above link does not exist. Anyways thanks for the explanation
  2. Q

    Commutator in QM vs. Lie brackets in DG

    Sir, But is it not a fallacy to equate operators on one side ,to real valued functions(classical observables) on the other? Plz Give me the link to the derivation in case i have got the entire concept wrong By the way I am absolutely sure that both PB and commutators define a Lie algebra...
  3. Q

    Commutator in QM vs. Lie brackets in DG

    The Algebra of The Poisson brackets studied in classical physics is the same as that of the commutator. ie[a,b]=ab-ba generates the same algebra as the poisson bracket of two classical observables a(p,q),b(p,q)
  4. Q

    Why do particles annhillate with their particles?

    why do particles annhillate with their particles? Why is an electron-positron bound state so short lived? In other words why does an electron readily anhillate its corresponding antiparticle(positron)?
  5. Q

    Black holes and particles

    i wasnt speaking of stellar collapse on chandrashekar limit. what i meant to say that any point like mass should have a swarzchild radius in the case of electrons it should be infinitely infinitely small
  6. Q

    Black holes and particles

    Correctly speaking all particles having mass should be a black and should have a small but finite swarchild radius,for example the electron,quarks etc are all black holes. But what would happen if two particles come within their swarzchild radius?
  7. Q

    Determining uncertanity from the wave equation

    the wavefunction in momentum space is the Fourier transform of the wavefunction in position space. therefore if the wavefunction is spread out in momenta space it is more concentrated in position space and Vice versa this is just the the property of a function and its Fourier transform.
  8. Q

    Imagining particles, fields and interactions

    Imagine that you never heard about particle before. For you the all the forces in nature are described by scalar,vector etc fields. now you calculate the hamilton of the field and the momentum of the field and you ill replace the the field say phi and its momentum by operators which...
  9. Q

    Quantization and fluid mechanics?

    i didnt know it would be so complicated has anyone written a paper on this? please elaborate on why to use a tensor?
  10. Q

    Quantization and fluid mechanics?

    Quantization and fluid mechanics?? Cant quantum field theory be applied to releativistic imcompressible fluids? cant the velocity vector field be quantized? will the pressure of the fluid play the role of the 4th component of the four vector? what would be the corresponding quanta? (I know...
  11. Q

    Vaccum fluctuations?

    Vaccum fluctuations? How to understand vacuum fluctuations mathematically without getting into the virtual particles that is so stereotypical of POP sci articles? Am i right in saying that the vacuum expectation value of the square of electric field is inversely proportional to the fourth...
  12. Q

    Quanta of massive vector fields

    thanks a lot belchman i know i was a confused
  13. Q

    Quanta of massive vector fields

    wait a minute this is getting a bit confusing in nuclear physics the pions are described by complex scalar fields and over there the neutral pion is decribed by the field 1/2*(phi+phi*),i think i read this in JJ Sakurai advanced QM Plz confirm
  14. Q

    Quanta of massive vector fields

    yes but Z0 field can be written as a linear combination of W+ and W- fields like in scalar fields right?to get a real valued field
  15. Q

    Quanta of massive vector fields

    but hadrons are not fundamental but thanks for clearing the doubt regarding w bosons
  16. Q

    Quanta of massive vector fields

    Are the W+,W- and Z0 the field quanta of the massive charged vector fields? ie Proca fields
  17. Q

    What really is a photon?

    An harmonic oscillator of frequency v,excited to an energy level n is equivalent to n photons.
  18. Q

    The exact meaning of the 4 components of the Dirac Spinor

    \PsiHow to intepret the four components of the dirac spinor? the volume integral of the \Psi^T*\Psi give the probability of finding the releativistic electron in a given volume of space but what exactly do the four components really mean. I have read in many Pop physics books that the 4...
  19. Q

    Visualizing quantum spin

    i don't think its a good idea to imagine electron spin just as you would imagine a spinning ball. An electron has spin even though its not spinning in the literal sense. That the electron possesses spin has been proved experimnetantally in stern -gerlachs experiment. One more thing is that...
  20. Q

    Creating Electrons: A Question from Feyman

    Thanks Doubt Cleared
  21. Q

    Creating Electrons: A Question from Feyman

    Fine the hamilton operator and number operator are constants of motion. Including the charge operator and momentum operator in the phi square non interacting field theories For example consider a cubic cavity of volume V. A Real scalar field ,so there are no charges Assume there are N quanta...
  22. Q

    Creating Electrons: A Question from Feyman

    From WHERE? "I remember that when someone had started to teach me about creation and annihilation operators, that this operator creates an electron, I said, "how do you create an electron? It disagrees with the conservation of charge" -R.P Feymnan I have a similar doubt someone please help
  23. Q

    Virtual Photons as Force Carriers

    Virtual particles are decribed by propogators where the propogator is <01 phi_-(x)*phi_+(x)10> where phi(x) is the operator field associated with the particle
  24. Q

    Why integral particle number?

    i think this is a little confusing I guess pell mann is asking why the eigenvalues of the number operator acting on Fock space is restricted to integral values. And why not a real quantity say like 12.5637 right? Well now does it it make any sense to say that so and so fock space is an...
  25. Q

    Integrating over all possible fields

    What does it really mean to integrate over all possible fields in the Path integral formulation of quantum field theory,and how does such a formalism goes out to decribe field quanta? Another question is im new to Quantum field theory i was wondering whether i should stick to the old...
  26. Q

    Four fermion interaction?

    four fermion interaction?? The four fermion interaction proposed by enrico fermi to learn weak interaction postulates that four dirac fields interact via the interaction hamilton J1^{}u*J2_{}u where J1^{}u=phi_d(x)*y^{}u*phi_c(x) but by question is this is the bilinear form taken...
  27. Q

    Proving the Spin Half Nature of Dirac Quanta

    but how to show it using quantum field theory? that is in terms of an operator which acts on a fock space having eigenvalue=sqrt(s(s+1)) times the number of quanta in the fock space im totally confused
  28. Q

    Proving the Spin Half Nature of Dirac Quanta

    well what about spin a1 fields,spin 3-2 fields,spin 2 fields how does one go about showing that they describe quanta of that much amount of intrinsic angular momenta
  29. Q

    Proving the Spin Half Nature of Dirac Quanta

    but I am confused how do you proof that the dirac field describes spin half quanta when quantized? please refer me to a link on the net where this derivation is shown if possible i can't find it in any of the books on quantized field theory
  30. Q

    Probability Amplitude phases

    Read the first few pages of QFT in Nutshell by ZEE The motivation for introducing path integral formulation of QM is startted as a doubt that feynmann had regarding the inteference of photon as it goes through a doble slit... please read further I cannot describe the hapiness that i...