Exploiting Maximally Mixed States for Spectral Estimation by Time Evolution

Understand

We introduce a novel approach for estimating the spectrum of quantum many-body Hamiltonians, and more generally, of Hermitian operators, using quantum time evolution.

• In our approach we are evolving a maximally mixed state under the Hamiltonian of interest and collecting specific time-series measurements to estimate its spectrum.
• We demonstrate the advantage of our technique over currently used classical statistical sampling methods.
• We showcase our approach by experimentally estimating the spectral decomposition of a 2-qubit Heisenberg Hamiltonian on an IBM Quantum backend.