How quantum mechanics cools hot electrons
will describe how we are in a new frontier of the quantum world---one where we begin to understand how quantum mechanics is involved in cooling electrons that have been excited far from equilibrium due to ultrafast and ultra-intense laser pulses. These so-called pump/probe experiments shine light onto the process of many-body relaxation which is one of the most complex situations to describe in the quantum world. I will show how pump/probe experiments are performed, why they need to be so fast, and how we can describe them with new advances in theory and computation. In particular, I will describe how electrons transfer energy to phonons in both the normal and superconducting states and how this behavior can be employed to observe exotic phenomena like Higgs oscillations.