Distinctness threshold for pseudorandom unitaries

Asad Raza, Jens Eisert, Bill Fefferman

Independent random one-qubit complex Cliffords, or exact one-qubit 2-designs, form a depth-one n-qubit tensor-product ensemble with entangled anticoncentration error (2/3)^n and negligible distinctness for polynomially many queries.

Sources for this record

What was already known

Earlier distinctness constructions used a unitary 2-design layer of at least logarithmic depth. The authors’ broader pseudorandom-unitary framework predated this model proposal.

AI involvement AI-centered

Raza, Eisert and Fefferman credit ChatGPT 5.6 Sol with proposing this nonentangling construction. They developed the broader framework and independently checked the proof.

The exact retained nonentangling Clifford construction is explicitly credited to ChatGPT, while the broader project and proof development are human-led.

Importance Notable

Shows that entanglement is unnecessary for the distinctness ingredient in the stated nonadaptive construction.

Limitations

The depth-one statement covers the distinctness ingredient; the final pseudorandom unitary also uses other components and is analyzed in the stated nonadaptive security model.

Technical verification Formal (human)

The named authors expressly report independently verifying all proofs, including Proposition III.5, and present its proof. This is source-reported completed human checking; no machine proof is documented.

Formal checking

Proposition III.5: independent one-qubit Clifford ensemble is (2/3)^n-EAC. Independent verification of all manuscript proofs, including the proposition

Checker
Asad Raza, Jens Eisert and Bill Fefferman
Scope
Proposition III.5: independent one-qubit Clifford ensemble is (2/3)^n-EAC
Basis
Reported by the linked checker
Evidence source

Checking a formal statement does not establish that it matches the original problem.

Human understanding Full

The authors explain why a tensor product of one-qubit Cliffords yields the exponential anticoncentration bound and how distinctness follows; no central mechanism is reported unexplained.

Correction and publication history