Numerically calculating the thermal noise of mirror coatings with multiple loss angles*

Reducing Brownian coating thermal noise is crucial for increasing the sensitivity of ground-based gravitational-wave detectors. One promising idea to decrease thermal noise is to use crystalline coatings. Modeling thermal noise from crystalline coatings is technically challenging. In this talk, I will discuss new numerical calculations that model Brownian coating thermal noise for crystalline coatings using the fluctuation-dissipation theorem. For simplicity, such calculations often approximate materials as having a single loss angle (loss angles, resulting from small imaginary parts of materials' elastic moduli, lead to dissipation). In this talk, I will present results that include different loss angles for different elastic moduli, and I will compare them to results using a single loss angle.