2019_EJRNL_PP_DAVIDE_GIROLAMI_1.pdf
Terbatas Ratnasari
» ITB
Terbatas Ratnasari
» ITB
Consider a quantum system prepared in an input state. One wants to drive it into a target state. Assuming
classical states and operations as free resources, I identify a geometric cost function which quantifies the
difficulty of the protocol in terms of how different it is from a classical process. The quantity determines a
lower bound to the number of commuting unitary transformations required to complete the task. I then
discuss the link between the quantum character of a state preparation and the amount of coherence and
quantum correlations that are created in the target state.