The Quantum PCP Conjecture (QPCP) claims that estimating ground-state energies of local Hamiltonians to constant precision is hard for quantum computers. If true, QPCP implies the existence of local Hamiltonians with non-trivial low-energy space properties, and a recent trend has been to construct (or conjecture) such Hamiltonians independently of QPCP. This proposal will focus on topics surrounding QPCP and one such implication, the No Low-energy Sampleable States (NLSS) Conjecture. The results accomplished thus-far include two necessary consequences of both QPCP and the NLSS Conjecture: constructions of No Low-energy Stabilizer States (NLCS) Hamiltonians and No Low-energy Almost-Clifford States (NLACS) Hamiltonians. After detailing why QPCP implies certain Hamiltonians we will examine the explicit construction of NLCS/NLACS Hamiltonians. Will also see how the construction can be adapted to yield simultaneous NLACS/No Low-energy Trivial States (NLTS) Hamiltonians, another prerequisite of QPCP. We will end with proposed research directions in both Hamiltonian complexity and quantum error correction which have connections to QPCP.
Nolan Coble is a PhD Student advised by Alexander Barg and Matthew Coudron. He is broadly interested in quantum complexity theory and quantum error correction.