The Spectral Foundations of Quantum Evolution

Stergios Pellis

Arkady Kurnosov, Sven Gnutzmann, Uzy Smilansky

In a recent paper, a semiclassical Lyapunov exponent associated with a quantum Hamiltonian represented by a finite-dimensional Hermitian matrix was defined and placed on a mathematical foundation. The Lyapunov exponent characterizes the early stages of the evolution toward the ergodic state, while the late stages are characterized by the spectral gap of the corresponding Markov matrix. Here, we apply this formalism to five random-matrix ensembles. For each ensemble, we derive the mean Lyapunov exponent, its variance, and the spectral gap as functions of energy. We also present the corresponding thermal averages. Extensive numerical data are compared with the theoretical predictions.

Saad Osman Awadelkareem

This paper develops the quantum sector of Grand Consistency Theory (GCT) from its underlying microscopic constraint structure. Starting from emergent Lorentzian spacetime and the Constraint Laplacian, the framework constructs the reversible sector, the associated spectral Hilbert space, and relational time evolution. Quantum dynamics is formulated through a Hamiltonian obtained as a spectral function of the Constraint Laplacian, leading to Schrödinger-type evolution within the emergent description. The paper further develops the symplectic structure of the reversible sector and relates quantum normalization to Planck’s constant. Observables are represented by self-adjoint operators, while spectral decomposition provides the basis for measurement probabilities and the Born-rule structure. Canonical position and momentum operators and their commutation relations are subsequently formulated within the same framework. The central objective is to present quantum mechanics as an emergent consequence of microscopic consistency dynamics rather than as an independent foundational postulate. The construction connects quantum states, dynamics, observables, measurement, and quantum normalization to a common spectral and constraint-based microscopic origin, providing the quantum-theoretical component of the broader Grand Consistency Theory research program.

Lucas Sá, Pedro Ribeiro, Sergey Denisov

Dissipative quantum chaos is an emerging theory that is expected to extend the ideas, concepts, and methodology of conventional Hamiltonian quantum chaos from coherent evolution to open quantum dynamics. The new theory should provide a set of tools to distinguish chaotic open quantum systems from integrable ones, as well as quantitative measures of their chaoticity (or, conversely, integrability). The foundations of this theory were laid in the late 1980s, and from the very start it was clear that, like its Hamiltonian predecessor, it had to be based on the spectral properties of the operators governing open quantum evolution. After these first steps, the field remained relatively quiet for many years and it is only over the last decade that the development of dissipative quantum chaos has received a strong boost, as confirmed by a large number of publications on this topic and, very recently, the first experiments performed to test its theoretical predictions. In this chapter, we review these recent developments and outline the basic foundations of dissipative quantum chaos.

Valter Moretti

Arno Böhm