Quantum State and Process Tomography of Energy Transfer Systems via Ultrafast Spectroscopy

TL;DR

This paper introduces a quantum process tomography method using polarization-controlled ultrafast spectroscopy to reconstruct the evolving quantum state of energy transfer systems, revealing detailed system-bath interactions.

Contribution

It presents a novel experimental protocol combining heterodyned photon-echo and quantum process tomography to analyze excited state dynamics in multichromophoric systems.

Findings

QPT reveals detailed system-bath interactions

Method reconstructs time-evolving density matrices

Provides comprehensive excited state dynamics analysis

Abstract

The description of excited state dynamics in multichromophoric systems constitutes both a theoretical and experimental challenge in modern physical chemistry. An experimental protocol which can systematically characterize both coherent and dissipative processes at the level of the evolving quantum state of the chromophores is desired. In this article, we show that a carefully chosen set of polarization controlled two-color heterodyned photon-echo experiments can be used to reconstruct the time-evolving density matrix of the one-exciton manifold of a heterodimer. This possibility in turn allows for a complete description of the excited state dynamics via quantum process tomography (QPT). Calculations on the dimer show that QPT can reveal rich information about system-bath interactions, which otherwise appear nontrivially hidden in the polarization monitored in standard four-wave mixing experiments. Our study presents a novel method for analyzing condensed phase experiments with a quantum information processing perspective.