Robust states in semiconductor quantum dot molecules

TL;DR

This paper investigates how spontaneous emission in semiconductor quantum dot molecules can lead to robust indirect exciton states, which are promising for quantum memory and gate applications due to their decoherence resistance.

Contribution

The study models decoherence effects in quantum dot molecules and demonstrates how spontaneous emission can stabilize indirect exciton states, enhancing quantum information processing potential.

Findings

Spontaneous emission promotes robust indirect exciton formation.

Robustness of states is controllable via external fields.

Potential for improved quantum memory and gate implementations.

Abstract

Semiconductor quantum dots coherently driven by pulsed laser are fundamental physical systems which allow studying the dynamical properties of confined quantum states. These systems are attractive candidates for a solid-state qubit, which open the possibility for several investigations in quantum information processing. In this work we study the effects of a specific decoherence process, the spontaneous emission of excitonic states, in a quantum dot molecule. We model our system considering a three-level Hamiltonian and solve the corresponding master equation in the Lindblad form. Our results show that the spontaneous emission associated with the direct exciton helps to build up a robust indirect exciton state. This robustness against decoherence allows potential applications in quantum memories and quantum gate architectures. We further investigate several regimes of physical parameters, showing that this process is easily controlled by tuning of external fields.