Quantum Hash Descriptor (QHD) This specification defines a robust and verifiable method for applying the QHD (Quantum Hash Descriptor) to physical entities across scientific, engineering and operational domains. Universal application is achieved through a domain-neutral core and versioned physical application profiles that declare entity boundaries, state spaces, observables, reference and time systems, dynamics or process models, quantitative uncertainty, admissible entropy semantics, persistence criteria, lineage rules, validation populations and interoperability mappings.