Explore the third class of a minicourse on Cosmological Phase Transitions and Gravitational Waves, presented by Benedict von Harling from IFAE-Barcelona. Delve into advanced concepts related to the intersection of cosmology, phase transitions, and gravitational wave physics. Gain insights from this 1 hour and 37 minute lecture, part of a comprehensive series organized by ICTP-SAIFR from February 10 to March 6, 2023. Enhance your understanding of cutting-edge research in theoretical physics and cosmology, and discover how these phenomena contribute to our knowledge of the early universe and its evolution.