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  1. K

    Decomposition reaction for theophylline, hexobarbital natrium

    Hello! There is a problem to write chemical reactions that goes with substances if they are not stored properly. For example theophylline should be saved from light and though I am trying to find its’ reaction with hv(light) but failed. Please help with some good reference Many thanks in advance
  2. K

    Good books on Group theory in High Energy physics

    I don't know your actual background but this textbook helped me a lot then Pierre Ramond "Group Theory a Physicist's survey" It was also good in the following manner. You might get basic ideas and concepts on groups from any HEP textbook but for some reasons you want to enlarge your knowledge...
  3. K

    Chemistry Chemistry textbook for Physicists

    Hello Being a professional physicist(Quantum field theory and HS theory) I'd like to learn chemistry for some reasons. I've already tried to find a nice Chemistry textbook but failed to find physicist friendly one. My last class on chemistry was in highschool like 11 years ago already, so my...
  4. K

    I Spinorial identity

    After some thinking and asking I believe that this identity may be true due different index structure of sigma matrices $$ \sigma_{\mu \alpha \dot{\alpha}}, \bar{\sigma}_\mu {}^{\dot{\alpha} \alpha}$$ If someone has a nice comprehensive refference on this spinor algebra issues I would be very...
  5. K

    I Spinorial identity

    Since it is involved in the contraction on r.h.s. of the identity it makes difference. This identity is true $$ A^\dagger \bar{\sigma}_\mu A=\bar{\sigma}_\nu\Lambda^\nu{}_\mu.$$ And it is kinda obvious. When I apply inverse SL(2,C) transformation it should result in inverse Lorentz...
  6. K

    I Spinorial identity

    Hi there! I am reading textbook "Supergravity" by Freedman and Van Proeyen and got stuck on a simple exercise (Ex 2.4). Usually I would proceed further marking it as a typo but I've checked the errata list on the website and didn't find this exercise there Exercise 2.4 Show that ##...
  7. K

    Exercise from Supergravity textbook

    1. Homework Statement In Ex. 2.4 from textbook Supergravity by Freedman and Van Proeyen one needs to prove the following identity $$ A^\dagger \sigma_\mu A=\sigma_\nu \Lambda^\nu{}_\mu $$ 2. Homework Equations It is easy to prove the other identity in this exercise $$ A\bar{\sigma}_\mu...
  8. K

    Bosonic Strings and their Verma modules

    If Virasoro algebra has not central charge, Verma modules with $h=1$ and $h=0$ are in some sense equivalent $$ \vert 1 \rangle = L_+ \vert 0 \rangle, $$ where $$ L_0 \vert 0\rangle =0 \;\; L_0 \vert 1 \rangle=-\vert 1 \rangle $$ Applying lowering operators $L_-$ $$ L_- L_+ \vert 0\rangle = (L_-...
  9. K

    Bosonic Strings and their Verma modules

    Hi there! I have som troubles with representation theory. It is obvious that bosonic strings fields $X^{\mu}$ has zero conformal dimension $h=0$. But when one builds Verma module (open string for example) highest weight state has the following definition $$ L_0 \vert h \rangle = 1 \vert h...
  10. K

    Grassmann integration

    I know that ##\theta## anticommute, but how one deduce that ##d\theta## obey the same rule
  11. K

    Grassmann integration

    Hi, everyone! I am trying to understand notation of this textbook http://arxiv.org/abs/hep-th/0108200 page 8, formulas 2.1.4 and 2.1.5 $$\int d \theta_\alpha \theta^\beta=\delta_\alpha^\beta$$ this could be found in any textbook the weird that from the above formula follows $$\int d^2...
  12. K

    Why is Lorentz Group in 3D SL(2, R)?

    Equal sign means that they are isomorphic. Equal algebras doesn't mean that group are isomorphic. O(3) and SO(3) have the same Lie algebra, but they are not isomorphic. Exponential map from algebra to group gives only simply connencted part. One can not build smooth curve from matrices with...
  13. K

    Birth of strings

    In string theory strings are fundamental, just electron or photon in SM
  14. K

    Why is Lorentz Group in 3D SL(2, R)?

    Lorentz group in three dimensions is SO(2,1) and it is NOT isomorphic to SL(2,R). SL(2,R) - is spin group in three dimensions with the signature mentioned above. SO(2,1)=SL(2,R)/Z_2 Majorana spinors are real because they are Majorana))) Definition of Majorana spinor
  15. K

    String theory-connecting strings

    In string theory Lorentz invariance preserved only in 26 dimension.
  16. K

    Transformation of auxiliary field

    By construction :-) You impose several conditions on your action and then get how auxilary fields should transform. Just like with YM gauge field, you want gauge invarianceand from this you get transformation law
  17. K

    Infinitesimal SUSY transformation of SYM lagrangian

    Lagrangian should be invariant off-shell, you are right. I am not an expert in this. But probably you need to introduce new field with purely algebraic equations of motion, like F in WZ model, just to cancel this term.
  18. K

    Infinitesimal SUSY transformation of SYM lagrangian

    Does the extra term vanish on the equations of motion?
  19. K

    S-matrix in String Theory

    I think I got the idea. Due to locality of Vertex Operators I can generate not just a state of a certain momenta but can actually put this state at a certain place. My problem was with understanding of constracting asymptotically free states which are needed in QFT as initial and final. In...
  20. K

    S-matrix in String Theory

    This point is not clear. Vertex operators generate single particle/string states without interaction, so this states are obviously free. And these states are our string |in> and |out> states. How to proceed to S-matrix from this point? If I understand you right. If we look from state...
  21. K

    S-matrix in String Theory

    Hi there! S-matrix is Path Integral with Vertex Operators inserted. I know how to compute Shapiro-Virasoro amplitude. So I don't have problems with calculations but with understanding. In this calculations formalism of 2-dimensional CFT is used. But there is no S-matrix in CFT, only...
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