My interest in Cosmology started back in the late 70's. However in the early 80's when Alllen Guth's first published his false vacuum inflation model accelerated that interest even further. That interest has been a primary focus of my studies ever since. Back then inflation often involved quantum tunnelling from a false vacuum state to a true vacuum state. These models typically had the energy density graph transitions as in a similar fashion to  https://www.wolframalpha.com/input?i2d=true&