At first glance, heat and cold do not have much to do with quantum physics. A single atom is neither hot nor cold. Temperature can traditionally only be defined for objects that consist of many particles. But at TU Wien, in collaboration with FU Berlin, Nanyang Technological University in Singapore and the University of Lisbon, it has now been possible to show what possibilities arise when thermodynamics and quantum physics are combined: One can specifically use quantum effects to cool a cloud of ultracold atoms even further.