Thermalization in a closed quantum system is defined by the dynamical approach of local observables toward universal expectation values, computed within a thermal Gibbs state. In this talk, I want to explain how a more refined notion of quantum equilibration can be studied by resolving the local state of a system via conditioning it on measurements of the complement (the “bath”). This yields an ensemble of pure conditional states — representing a physically motivated unraveling of the reduced density matrix — that describes a wavefunction distribution over the Hilbert space. I will show that for generic complex quantum systems, the ensemble attains a common form: it tends towards the “maximally entropic” distribution subject to constraints from conservation laws, which has the special quantum information-theoretic property of possessing minimal accessible information. This constitutes a form of equilibration beyond standard quantum thermalization, which has been dubbed “deep thermalization”. I will demonstrate the universality of this phenomenon across the physically distinct systems of discrete-variable spin systems and continuous-variable bosonic Gaussian systems, where deep thermalization takes different forms but is still governed by the same principle. Our results demonstrate the power of quantum information theoretic frameworks in unveiling new physical phenomena and principles in quantum dynamics and statistical mechanics.