Dephasing in the adiabatic rapid passage in quantum dots: the role of phonon-assisted biexciton generation

TL;DR

This paper investigates how phonon interactions cause decoherence during adiabatic rapid passage in quantum dots, especially due to biexciton generation, highlighting the limitations for efficient state preparation at low temperatures.

Contribution

It provides a detailed analysis of phonon-assisted biexciton generation effects on decoherence in adiabatic control of quantum dots, emphasizing the impact of biexciton energy shifts.

Findings

Decoherence is significant when the biexciton state is shifted down by a few meV.

Efficient state preparation occurs only at low temperatures, positive chirps, and moderate pulse areas.

Phonon-assisted biexciton generation limits the fidelity of adiabatic control in quantum dots.

Abstract

We study the evolution of an exciton confined in a quantum dot adiabatically controlled by a frequency-swept (chirped) laser pulse in the presence of carrier-phonon coupling. We focus on the dynamics induced by a linearly polarized beam and analyze the decoherence due to phonon-assisted biexciton generation. We show that if the biexciton state is shifted down by a few meV, as is typically the case, the resulting decoherence is strong even at low temperatures. As a result, efficient state preparation is restricted to a small parameter area corresponding to low temperatures, positive chirps and moderate pulse areas.