Hybrid Monte Carlo, or HMC, is a kind of computer simulation that uses random numbers (called Monte Carlo) and math (called calculus) to try and predict results. This type of simulation is often used to study and model physical processes, like how atoms move, weather, or anything else that has a lot of variables and unknowns. To do this, it uses a lot of random numbers to mimic how certain things might happen in reality. Then, it uses calculus to check the accuracy of the simulation. HMC uses both of these tools to make predictions that would be too difficult to calculate with just math alone.