Hamiltonian engineering for quantum sensing

Quantum sensing utilizes the interaction between the quantum sensor and the object to be detected. However, limited by the intrinsic system Hamiltonian or experimental capabilities, the implementable Hamiltonian evolution may not be optimal to reveal the information of the target object. Inspired by digital quantum simulation, here we present a general framework in which we use Trotter-like combinations of unitaries to engineer better Hamiltonians for sensing and provide an efficient protocol to reduce the approximation error. We show the application of Hamiltonian engineering to nano-scale magnetic resonance imaging.