Quantum Information Supports Delayed Decisions

Chatbots, search engines and Database Query Systems are invaluable sources of information for decision-making processes in the data-driven world in which we live today. In this study, we explore the extent to which classical and Quantum Query Systems can support future decisions, taken at a moment where the query service may be inaccessible and the decision has to be based solely on information collected in the past. We show that encoding information at the quantum level allows Query Systems to support future or delayed decisions. More precisely, Grover’s algorithm can be employed in order to extract the desired answer from a large superposition of question–answer pairs obtained through a single interrogation of the system. The method works best for binary answers and can be applied to queries encompassing hundreds or thousands of questions in one query. Extensions are possible if we allow more than one query to be addressed to the system. By comparison, a classical system would require hundreds or thousands of queries in order to offer the same level of support for delayed decisions.