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arXiv · 2509.10131

Exact Classicalization of N-Level Quantum Systems Interacting with a Bath: Theory and Applications

Daniel Martínez-Gil·Pedro Bargueño·Salvador Miret-Artés
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Abstract

In this manuscript, starting from a five-step algorithmic procedure for exactly classicalizing the dynamics of N-level quantum systems, we incorporate a classical bath of harmonic oscillators to model environmental interactions. Using the geometry of complex projective spaces CP(N-1) and a Langevin formalism, we obtain N-1 Hamilton's equations which encode both the quantum system and the bath degrees of freedom, representing a generalization of the Caldeira-Legget model in a complex projective space. We demonstrate the efficacy of the method by applying it to two paradigmatic systems: a two-qubit system in CP(3) under entangling interactions, reproducing quantum observables such as state populations, quaternionic population differences and concurrence, and the seven-state Fenna-Matthews-Olson (FMO) complex in CP(6), reproducing state populations in the picosecond timescale.

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Daniel Martínez-Gil, Pedro Bargueño, Salvador Miret-Artés. 2025-09-12. Exact Classicalization of N-Level Quantum Systems Interacting with a Bath: Theory and Applications. https://arxiv.org/abs/2509.10131

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