Quantum Theory and Quantum Field theory derived from information-theoretic principles

by Giacomo Mauro D'Ariano

Monday 26 Sept 2016, 14:30 → 16:00 Europe/Rome

Aula Conversi (Dip. di Fisica - Edificio G. Marconi)

I will review a recent derivation of free quantum field theory from axioms of information theoretic nature, from countably many systems with interactions satisfying the requirements of locality, homogeneity, and isotropy. It follows a theory of quantum cellular automata encompassing a discrete Planck scale, with maximum value for the Dirac mass (Planck mass) as a consequence of the unitariety condition, and recovering the usual field theory in the relativistic limit of small wave-vectors. The theory predicts measurable effects visible in principle from deep-space high energy events. Special relativity is recovered from pure quantum, without using space time. The Poincare group is distorted at Planck scale, and is perfectly recovered for small wave-vectors. The notion of particle as Poincaré invariant survives. For strong boosts or large masses also the rest-mass is transformed, leading to a De Sitter covariance. We have thus two emerging features with GR flavor: maximum mass and De Sitter covariance. Very recently the interacting theory has been addressed, starting with the one-dimensional case which satisfies the locality axiom, corresponding to an Hubbard Fermionic automaton which is analytically solved by the Bethe ansatz. Numerical evaluations of the automata will be shown, and a simple asymptotic analytical approach will be given that allows to derive a general dispersive Schroedinger equation holding in all regimes for narrow-band states describing quantum particles.