Direct quantum process tomography with coupling-deformed pointer observables

Weak-value tomography has been experimentally verified to be superior to the standard methods in the degree of directness, and the simplicity of implementations. Moreover, the problem of low efficiency, which arises from the reliance on weak measurements, has been cured by the very recent proposal of the coupling-deformed pointer observables [Phys. Rev. A 93.032128 (2016)]. In this article, we develop a modified version of weak-value tomography to cover the tomography of quantum dynamical processes. We show that each parameter of the unknown process is directly determined by two sequential measurements, regardless of how large the dimensions of the systems are. The scheme has simple input preparation, requiring only states that form an orthonormal basis.