3 papers
quant-ph2025
A Class of Cyclic Quantum Codes
Matthew B. Hastings
We introduce a class of cyclic quantum codes, basing the construction not on the simplicity of the stabilizers, but rather on the simplicity of preparation of a code state (at leas…
quant-ph2025
A Sparse Chain Complex Without a Sparse Lift
Matthew B. Hastings
We construct a sparse chain complex (with three different degrees, so that it corresponds to a quantum code) which does not admit a sparse lift to the integers, answering a q…
quant-ph2024
Improving Perturbation Theory with the Sum-of-Squares: Third Order
M. B. Hastings
The sum-of-squares method can give rigorous lower bounds on the energy of quantum Hamiltonians. Unfortunately, typically using this method requires solving a semidefinite program,…