Irreversibility and symmetries in quantum theory
The concept of irreversibility is typically associated with classical thermodynamics, and the inexorable decrease of free energy. However, with progress into more extreme quantum regimes, there is increasing foundational interest to deepen our conception, and to frame irreversibility more broadly. Here I shall describe progress towards a symmetry-based framework for the irreversibility of general quantum resources. Such a framework identifies features within thermodynamics that cannot be captured by any free energies, displays structural parallels with entanglement theory, and more generally provides a language with which to describe quantum processes in the presence of conservation laws.