Some observations on quantum mechanics in disordered systems

David A. Evensky

Georg Kucsko, Soonwon Choi, Joonhee Choi +10 more

Statistical mechanics underlies our understanding of macroscopic quantum systems. It is based on the assumption that out-of-equilibrium systems rapidly approach their equilibrium states, forgetting any information about their microscopic initial conditions. This fundamental paradigm is challenged by disordered systems, in which a slowdown or even absence of thermalization is expected. We report the observation of critical thermalization in a three dimensional ensemble of ∼10^{6} electronic spins coupled via dipolar interactions. By controlling the spin states of nitrogen vacancy color centers in diamond, we observe slow, subexponential relaxation dynamics and identify a regime of power-law decay with disorder-dependent exponents; this behavior is modified at late times owing to many-body interactions. These observations are quantitatively explained by a resonance counting theory that incorporates the effects of both disorder and interactions.

H. le Sueur, Artis Svilans, Nicolas Bourlet +4 more

By performing experiments with thin-film resonators of NbSi, we elucidate a decoherence mechanism at work in disordered superconductors. This decoherence is caused by charged Two Level Systems (TLS) which couple to the conduction electrons in the BCS ground state; it does not involve any out-of-equilibrium quasiparticles, vortices, etc. Standard theories of mesoscopic disordered conductors enable making predictions regarding this mechanism, notably that decoherence should increase as the superconductor cross section decreases. Given the omnipresence of charged TLS in solid-state systems, this decoherence mechanism affects, to some degree, all experiments involving disordered superconductors. In particular, we show it easily explains the poor coherence observed in quantum phase slip experiments and may contribute to lowering the quality factors in some disordered superconductor resonators.

V. Dobrosavljević

Reiner Kree

hassan ali hassan alanbki, taha ali hassan alanbki

This work introduces a foundational interpretive framework for quantum mechanics based on a single organizing principle: the temporal mismatch between observer and system. The framework proposes three fundamental laws of quantum time, explaining quantum indeterminacy, wavefunction collapse, entanglement, and the quantum–classical transition without modifying the mathematical formalism of quantum mechanics. Quantum behavior is interpreted not as intrinsic disorder, but as a consequence of observing systems whose intrinsic dynamical time scales differ radically from the temporal resolution of measurement. This work is intended as a conceptual and foundational contribution, offering a unified interpretive structure for ongoing discussions in the foundations of quantum mechanics. The framework is operationally defined and falsifiable in principle, though not directly testable with current experimental capabilities.