Compressed sensing for Hamiltonian reconstruction

Understand

In engineered quantum systems, the Hamiltonian is often not completely known and needs to be determined experimentally with accuracy and efficiency.

• We show that this may be done at temperatures that are greater than the characteristic interaction energies, but not too much greater.
• The condition for this is that there are not too many interactions: the Hamiltonian is sparse in a well-defined sense.
• The protocol that accomplishes this is related to compressed sensing methods of classical signal processing; in this case applied to sparse rather than low-rank matrices.