Coherent manipulation of electronic states in a double quantum dot

TL;DR

This paper demonstrates the coherent control and manipulation of charge states in a double quantum dot system, revealing oscillations and discussing decoherence mechanisms relevant for quantum computing applications.

Contribution

It introduces a fully tunable charge qubit in a double quantum dot and demonstrates high-speed voltage pulse control of its quantum states.

Findings

Observation of coherent oscillations in charge states

Identification of decoherence mechanisms

Control of qubit energy and decoherence with voltage pulses

Abstract

We investigate coherent time-evolution of charge states (pseudo-spin qubit) in a semiconductor double quantum dot. This fully-tunable qubit is manipulated with a high-speed voltage pulse that controls the energy and decoherence of the system. Coherent oscillations of the qubit are observed for several combinations of many-body ground and excited states of the quantum dots. Possible decoherence mechanisms in the present device are also discussed.