Thermal Dark Energy

I will present a new proposal to explain dark energy, which is motivated by the prevalence of hidden sectors in string theory models and by recent swampland conjectures against dS string vacua.
In Thermal Dark Energy, thermal effects hold a light hidden sector scalar at a point in field space that is not a minimum of its zero temperature potential, leading to an effective cosmological constant, with an equation of state w=-1, despite the scalar's zero temperature potential having only a 4D Minkowski or AdS vacuum.
I will discuss the phenomenologically viable parameter space, cosmological history and observational signals of the model, including a possible resolution of the H_0 tension.