Direct reconstruction of the quantum-master-equation dynamics of a trapped-ion qubit

The physics of Markovian open quantum systems can be described by quantum master equations. These are dynamical equations that incorporate the Hamiltonian and jump operators and generate the system's time evolution. Reconstructing the system's Hamiltonian and its coupling to the environment from measurements is important both for fundamental research and for performance evaluation of quantum machines. Here we introduce a method that reconstructs the dynamical equation of open quantum systems, directly from a set of expectation values of selected observables. We benchmark our technique both by a simulation and experimentally, by measuring the dynamics of a trapped Sr-88(+) ion qubit under spontaneous photon scattering.