{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.topic/1","content_sha256":"537c488de54668d1d7701a8507acbd761ddc3f654a7c525235b1b33cb19709d7","created":"2026-10-03T07:17:53Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":[],"salt":"bb52cd997ee972e932e161d1ae4a126f055de5b2587c0fb57e85d9a6e7000f21","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"topic"},"content":{"external_id":"qi.sic-mub","field":"qi","n":"1","review_cite":"P. Horodecki, L. Rudnicki and K. Zyczkowski, Five open problems in quantum information theory, PRX Quantum, 2022","review_link":"https://arxiv.org/abs/2002.03233","review_verified":"true","summary":"A quantum measurement can be built from a set of equally spaced states, the quantum analogue of a perfectly symmetric arrangement of points on a sphere. Whether such sets exist in every dimension, and how many mutually unbiased bases (measurement bases where knowing one outcome tells nothing about the others) exist in dimension 6, are unsolved.","title":"SIC-POVMs and mutually unbiased bases","topic_ref":null,"why":"These objects give optimal schemes for state reconstruction and cryptography and are tied to deep questions in number theory."},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"1bdfc0d09903d73034d6e6510c6d21f380d002328cb4a356dee914b540fb53cc","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"107c52b5f73839a9c0bd42c227032118b76c7fca93df32e67fc02d8ec5780737","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"bgNX3mUNFB-gvlCRXmqSbqVMNBzOe_VdBxUhJUxbKakatrzvwX_VMTLksegejb2kpJ8e3LvJwXowOEpywmMyCA"},"schema":"pubphys.envelope/1"},"record_hash":"1bdfc0d09903d73034d6e6510c6d21f380d002328cb4a356dee914b540fb53cc","leaf_index":346}