Consider the accepting POVM ($\Pi$, $I-\Pi$) of a fixed QMA machine. Let d be the number of eigenstates of $\Pi$ that are at least 2/3. Decide if d is at least some fixed s, or at most s/2. This i...
The complexity class QMA(2) has no known upper bounds aside from NEXP. It is unknown whether this class lies in BQEXP, which gives a quantum computer exponential time to decide a problem with $\ge ...
QAC0 is the class of constant-depth quantum circuits with single-qubit gates and Toffoli gates. Is QAC0 with fanout more powerful than QAC0 with fanout *only allowed at the beginning of the circuit...
What is the complexity of computing the ground state energy of the EPR Hamiltonian? The EPR Hamiltonian is a quantum Hamiltonian defined on a graph where each edge contains a projector onto the sym...