GregM, RickS, DarkhanT, SudarshanK

We took a 10 hour long lock-stretch from ER8 and studied if there is a significant change in the time varying parameters, kappa_tst, kappa_pu, kappa_C, kappa_A and cavity pole which are described in details in DCC document T1500377. The plots of these parameters are attached below.

The real part of these parameters represents the actual change. There is no significant variation in these paramaetrs within this lock stretch. There is definitely some indiication that the variation is more during the first half hour of the lock and stabilizes after that. Essentially, these  numbers should be 1 (are set at 1 at some point in time) and the imaginary part of these parameters should  be zero or insignificant, however, the second plot doesnot show that. The reason might be because we are using the Calibration model form ER7 which is not the true representation of interferometer at which this data was taken plus we didnot account for time delays. However, we were only intrested in knowing the change in these parameters so this analysis was sufficient for that purpose.  We will do a more thorough study once we have the new calibration model ready.

We are also looking into how these parameters are changing over a long period of time (entire ER8). The analysis is ongoing and we will post the result soon.