Crossover from Bosonic to Fermionic features in Composite Boson Systems

TL;DR

This paper investigates how composite bosons transition to fermionic behavior at higher densities, analyzing quantum dynamics, tunneling, and energy transfer in complex systems with potential experimental implications.

Contribution

It introduces a theoretical framework for understanding the crossover from bosonic to fermionic features in composite systems, including the role of exceptional points and energy transfer mechanisms.

Findings

Identification of exceptional points under testable conditions

Analysis of tunneling dynamics in confined systems

Extension to energy transfer in photosynthetic complexes

Abstract

We study the quantum dynamics of conversion of composite bosons into fermionic fragment species with increasing densities of bound fermion pairs using the open quantum system approach. The Hilbert space of $N$-state-function is decomposed into a composite boson subspace and an orthogonal fragment subspace of quasi-free fermions that enlarges as the composite boson constituents deviate from ideal boson commutation relations. The tunneling dynamics of coupled composite boson states in confined systems is examined, and the appearance of exceptional points under experimentally testable conditions (densities, lattice temperatures) is highlighted. The theory is extended to examine the energy transfer between macroscopically coherent systems such as multichromophoric macromolecules (MCMMs) in photosynthetic light harvesting complexes.