Quantum thermodynamics

Quantum thermodynamics is the emerging field that studies how the laws of thermodynamics apply to quantum systems, and how quantum information and energy flow together under the constraints of quantum mechanics. It extends stochastic thermodynamics to the quantum regime, where coherence, entanglement, and the No-Cloning Theorem impose new limits on what can be done with heat and work. The central question is whether quantum coherence can be used to extract work more efficiently than classical thermodynamics allows, or whether quantum mechanics imposes additional irreversibilities that classical thermodynamics misses.

The field connects quantum information theory to thermodynamics in a deep and practical way: the Landauer principle — that erasing one bit of information requires at least kT ln 2 of work — is a quantum result in disguise, and its quantum generalizations govern the energy costs of quantum computation and communication. Quantum thermodynamics is not merely theoretical; it is the framework within which any future quantum engine, quantum refrigerator, or quantum biological energy transducer must be designed.