Giacomo Mauro D'Ariano

D'Ariano and his collaborators introduced the first exact algorithm for quantum homodyne tomography of states,[9] and they subsequently generalized the technique used to do to a universal method of quantum measurement.[10] D'Ariano then developed the first experimental scheme—now called "ancilla-assisted tomography"—that made the characterization of quantum channels, operations, and measuring apparatuses feasible to be actually done in the laboratory, by exploiting a single entangled input state.[11]

D'Ariano proposed quantum entanglement as a tool for improving the precision of quantum measurement,[12] an idea that, parallel to works of other authors, suggested the new field of Quantum metrology. He has also introduced several new types of measurement. With his team, he solved a number of long-standing problems of quantum information theory, such as the optimal broadcasting of mixed states;[13] the optimal phase-estimation for mixed states,[14] and the optimal protocols for phase cloning.[15]

D'Ariano and collaborators introduced the concept of "quantum comb",[16] which generalizes that of "quantum operation", and has a wide range of applications in optimization of quantum measurements, communication, algorithms, and protocols. He and his group subsequently used quantum combs to find the optimal apparatuses for Quantum tomography.[17] The quantum-comb framework also enabled a new understanding of causality in quantum mechanics and quantum field theory. This understanding had a wide and diverse impact in several areas of research, beginning with the study of quantum causal interference and causal-discovery algorithms, used in recent attempts, along quantum informational lines, at reconciling quantum theory and general relativity, one of the great outstanding problems of fundamental physics.[18]

D'Ariano has played a major role in making quantum information theory a new paradigm for the foundations of quantum theory and fundamental physics in general. In 2010, he proposed a set of information-theoretical postulates for a rigorous derivation of (finite-dimensional) Quantum Theory,[19] a derivation subsequently achieved in his collaboration with Giulio Chiribella and Paolo Perinotti.[20] This project also led to a new way of understanding, working with, and developing quantum theory, presented in a comprehensive textbook entitled Quantum Theory from First Principles.[21]

In the mid 2010s, D'Ariano extended this program to a derivation of Quantum Field Theory from informational-theoretical postulates, which enabled him and his team to derive the complete free Quantum field theory.[22] In an article in New Scientist, Lucien Hardy wrote that "their work and their approach is extraordinary", and Časlav Brukner wrote that he was "impressed" by their work writing that "there's something deep about quantum mechanics in this work".[23]

A historical perspective, from Dirac's discovery of quantum electrodynamics to the present time, on this work was given by Arkady Plotnitsky in The Principles of Quantum Theory, From Planck's Quanta to the Higgs Boson.[24] A book by Oliver Darrigol offers an extensive commentary on D'Ariano and co-workers' derivation of Quantum Mechanics, especially emphasizing how it overcomes certain ad hoc assumptions of previous derivations.[25]

On the formulation of quantum theory based on information principles, physicist Federico Faggin based his theory on the nature of consciousness.[26]