= Simulation meeting 2020 Aug 19, 15:00- =

== Participants ==
Somiya, Wang, Kokeyama, Koyama, Hirose, Yuzu

== Minute ==
=== Updates from Projects ===

 * Birefringence modeling (Haoyu)
    * Haoyu rose an interesting question if this BS-birefringence model can really simulate the real S and P fields or not. Sinsce "i" is added when the EM fields transmit the BS in finesse (for energy conservation), using a BS to split S and P pols, there are sign flips inside the S-P coupled cavity model. See, his [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11792|Birefringence model.pdf]], especially page 4. The P-pol cavity (P-PRM) field going back to the S-pol cavity (S-PRM) gets -1 (two transmissions at BS, therefore i*i), which is the flipped sign compared with the S field inside the S-PRM cavity. Isn't that true for the actual ITM birefringence mirror?
    * How the relative phase between S and P are when they transmit and reflect by optics in reality? Are there only phase delay on the mirror surface but no sign difference for S and P, if so, can the energy be conserved in that case? Or do one of S or P actually have to have phase flip compared with the other? 
    * We will have to understand the reality to evaluate the simulation.

 * IFO modeling (Keiko)
   * [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11857|Note on FPMI]]
    * Done (one disagreement in the matrices)
    * Comparison v.s. analytical calculation
   * [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=11858|Note on PRFPMI]]
    * Mostly done (a few disagreement in the matrices)
   * DRFPMI model
    * kat and jupyter notebook are on git, to be tested
   * Include the higher order modes (FPMI, PRFPMI, DRFPMI)
    * Haven't started


 * Simulation Interface (Koyama, Hirose, Yuzu)
   * Yuzu-san, Hirose-san, Koyama-san are visiting Kamioka this week until the middle of next week.
   * They made a first GUI box to put a optical parameter to pass to a finesse model.
   * [[KAGRA/Subgroups/MIF/Simulation/KamikokaActivity20200817 | Activity log]]