Models of Short-Time Qubit Decoherence

TL;DR

This paper compares different models for understanding qubit decoherence at low temperatures, showing that a non-Markovian approximation accurately predicts system behavior over relevant timescales for quantum computing.

Contribution

It demonstrates that non-Markovian approximation schemes provide reliable estimates of qubit decoherence in low-temperature environments, validated through an exactly solvable model.

Findings

Non-Markovian models yield accurate decoherence estimates.

Markovian approximations are less accurate at relevant timescales.

The approach is suitable for quantum computing design evaluations.

Abstract

We compare approaches to evaluation of decoherence at low temperatures in two-state quantum systems weakly coupled to the environment. By analyzing an exactly solvable model, we demonstrate that a non-Markovian approximation scheme yields good quality estimates of the reduced density matrix for time scales appropriate for evaluation of quantum computing designs.