A derivation of the conditions under which bosonic operators exactly capture fermionic structure and dynamics

TL;DR

This paper establishes the precise conditions under which fermionic systems can be mapped onto bosonic operators, enabling the use of simpler dynamical methods while preserving the essential fermionic behavior.

Contribution

It derives a set of conditions for exact fermion-to-boson operator mappings, guiding their application in simulating many-electron dynamics accurately.

Findings

Identifies conditions for bosonic operators to replicate fermionic dynamics

Demonstrates the approach with exact simulations of the resonant level model

Provides a practical guide for calculating correlation functions in transport phenomena

Abstract

The dynamics of many-body fermionic systems are important in problems ranging from catalytic reactions at electrochemical surfaces, to transport through nanojunctions, and offer a prime target for quantum computing applications. Here we derive the set of conditions under which fermionic operators can be exactly replaced by bosonic operators that render the problem amenable to a large toolbox of dynamical methods while still capturing the correct dynamics of the $n$-body operators. Importantly, our analysis offers a simple guide on how one can exploit these simple maps to calculate nonequilibrium and equilibrium single- and multi-time correlation functions essential in describing transport and spectroscopy. We use this to rigorously analyze and delineate the applicability of simple yet effective Cartesian maps that have been shown to correctly capture the correct fermionic dynamics in select models of nanoscopic transport. We illustrate our analytical results with exact simulations of the resonant level model. Our work provides new insights as to when one can leverage the simplicity of bosonic maps to simulate the dynamics of many-electron systems, especially those where an atomistic representation of nuclear interactions becomes essential.