Quantum-to-classical transduction denotes dynamical processes through which localized microscopic quantum events produce cumulative modifications of mesoscopic and macroscopic classical behavior in hybrid quantum-classical (HQC) systems. Understanding how such cross-scale influence emerges is a central problem in nonequilibrium physics and in the study of complex multiscale systems. Here, we develop a general dynamical perspective in which quantum-to-classical transduction arises naturally in hybrid quantum-classical systems, where quantum degrees of freedom interact continuously with classical environments. From this perspective, we identify physical conditions enabling transduction, including separation of dynamical timescales, metastable classical configurations acting as free-energy reservoirs, environmental fluctuations, and nonlinear feedback between quantum observables and classical motion. These ingredients define distinct dynamical regimes of transduction in hybrid systems. The quasi-Lie bracket formulation of HQC dynamics provides a general description of the coupled evolution, with the quantum-classical Liouville equation representing a minimal realization of the framework. Representative physical contexts in which microscopic quantum processes may influence large-scale dynamics are discussed, including plasmas, driven dissipative media, gravitationally coupled systems, and organized biological matter.
- Open Access
- Article
Quantum-to-Classical Transduction in Complex Physical Systems
- Alessandro Sergi 1,2,*,
- Antonino Messina 3,
- Gabriella Martino 4,
- MIchael A. Nitsche 5,6,7,
- Maria Teresa Caccamo 1,
- Salvatore Magazù 1
Author Information
Received: 02 Mar 2026 | Revised: 20 Jul 2026 | Accepted: 10 Aug 2026 | Published: 09 Sep 2026
Abstract
Keywords
quantum-to-classical transduction | hybrid quantum-classical dynamics | nonequilibrium systems | complex systems | multiscale dynamics | open quantum systems
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