Remove carrier density noise from pygwinc

Based on the new calculation with Debye screening from arXiv:2003.05345, there appears to be no plausible scenario where this noise will affect the design of GW interferometers. Koji estimated the noise is below 1e-28/rtHz for Voyager, as did Florian Bruns (lead author of arXiv:2003.05345). It's also negligible for ET, as discussed in the paper.

Fixes #50 (closed)

gwinc/ifo/Aplus/ifo.yaml

@@ -193,19 +193,19 @@ Materials:
   ## Dielectric coating material parameters----------------------------------
   Coating:
     ## high index material: tantala
-    Yhighn: 124e9                 # LMA (Granata at LVC) 2017 (was 140)
-    Sigmahighn: 0.28              # LMA (Granata at LVC) 2017 (was 0.23)
+    Yhighn: 120e9                 # Ta2O5-TiO2 from 2020 LMA https://iopscience.iop.org/article/10.1088/1361-6382/ab77e9
+    Sigmahighn: 0.29              # 2020 LMA
     CVhighn: 2.1e6                # Crooks et al, Fejer et al
     Alphahighn: 3.6e-6            # 3.6e-6 Fejer et al, 5e-6 from Braginsky
     Betahighn: 1.4e-5             # dn/dT, value Gretarrson (G070161)
     ThermalDiffusivityhighn: 33   # Fejer et al
-    Indexhighn: 2.06539
+    Indexhighn: 2.09              # 2020 LMA
     Phihighn: 9.0e-5              # tantala mechanical loss
     Phihighn_slope: 0.1
 
     ## low index material: silica
-    Ylown: 72e9
-    Sigmalown: 0.17
+    Ylown: 70e9                   # 2020 LMA
+    Sigmalown: 0.19               # 2020 LMA
     CVlown: 1.6412e6              # Crooks et al, Fejer et al
     Alphalown: 5.1e-7             # Fejer et al
     Betalown: 8e-6                # dn/dT,  (ref. 14)