IQC Math and CS seminar featuring Andrew Huang

Thursday, November 26, 2026 1:00 pm - 2:00 pm EST (GMT -05:00)

A quantum oracle separation between QMA(2) and QMA

Andrew Huang | UC Berkeley

We find a quantum oracle relative to which 𝖰𝖬𝖠≠𝖰𝖬𝖠(2). As a consequence, we resolve the no-disentanglers conjecture of Watrous: for every ϵ+δ<1, any (ϵ,δ)-disentangler requires input size exponential in the number of output qubits. Our proof combines the unitarily invariant polynomial method of She and Yuen (ITCS '23) with a new construction based on the symmetric and antisymmetric subspace projectors, reducing the 𝖰𝖬𝖠 lower bound to the approximate degree of OR.