Coherence time analysis in semiconducting hybrid qubit under realistic experimental conditions

TL;DR

This paper investigates the coherence times of hybrid qubits in semiconductor quantum dots under realistic experimental conditions, considering environmental noise sources like nuclear spins and charge traps.

Contribution

It provides a detailed analysis of hybrid qubit coherence times incorporating environmental noise effects in various host materials, using experimentally feasible parameters.

Findings

Coherence times vary significantly across different host materials.

Environmental noise sources notably impact qubit coherence.

Hybrid qubits in silicon show longer coherence times than in GaAs.

Abstract

The unavoidable effect of the environmental noise due to nuclear spins and charge traps is included in the study of the hybrid qubit dynamics. Hybrid qubit dues its name to the advantageous combination of manipulation speed of a charge qubit with the longevity of a spin qubit. It consists of three electrons confined through external gate voltages in a double quantum dot and deserves special interest in quantum computation applications due to its advantages in terms of fabrication, control and only electrical manipulation. Hybrid qubit is protected against global magnetic fluctuations since it is a decoherence-free subspace qubit. It is only affected by local fluctuations, such as the Overhauser field, in addition to charge fluctuations on the electrostatic gates. In the configuration studied, the control parameters, that are the gate voltages, are always turned on. Coherence time of the hybrid qubit is extracted when model parameters take values achievable experimentally in the nuclear free isotope $^{28}$Si, natural Si and GaAs hosts.