Physics as quantum information processing1

Giacomo Mauro D’Ariano

QUIT Group, Dipartimento di Fisica “A. Volta”, 27100 Pavia, Italy, http://www.qubit.it

Istituto Nazionale di Fisica Nucleare, Gruppo IV, Sezione di Pavia

Abstract. The experience from Quantum Information has lead us to look at Quantum Theory (QT)

and the whole Physics from a different angle. The information-theoretical paradigm—It from Bit—

prophesied by John Archibald Wheeler is relentlessly advancing. Recently it has been shown that

QT is derivable from pure informational principles. The possibility that there is only QT at the

foundations of Physics has been then considered, with space-time, Relativity, quantization rules

and Quantum Field Theory (QFT) emerging from a quantum-information processing. The resulting

theory is a discrete version of QFT with automatic relativistic invariance, and without fields,

Hamiltonian, and quantization rules. In this paper I review some recent advances on these lines. In

particular: i) How space-time and relativistic covariance emerge from the quantum computation; ii)

The derivation of the Dirac equation as free information flow, without imposing Lorentz covariance;

iii) the information-theoretical meaning of inertial mass and Planck constant; iv) An observable

consequence of the theory: a mass-dependent refraction index of vacuum. I will then conclude with

two possible routes to Quantum Gravity.

This paper is too vague in my opinion. Too much excess baggage.