Dual-probe decoherence microscopy: Probing pockets of coherence in a decohering environment

TL;DR

This paper introduces a dual-qubit decoherence microscopy technique that uses two probes to detect and analyze localized coherence pockets within a complex, decohering environment, revealing new dynamics and measurement advantages.

Contribution

The study models a tripartite system with two qubits and an environmental TLS, demonstrating how dual probes can extract detailed environmental parameters and uncover non-Markovian effects.

Findings

All TLS parameters can be inferred from a single probe measurement.

Dual-qubit configuration offers advantages in environmental probing.

Identification of decoherence-free states and non-Markovian dynamics.

Abstract

We study the use of a pair of qubits as a decoherence probe of a non-trivial environment. This dual-probe configuration is modelled by three two-level-systems which are coupled in a chain in which the middle system represents an environmental two-level-system (TLS). This TLS resides within the environment of the qubits and therefore its coupling to perturbing fluctuations (i.e. its decoherence) is assumed much stronger than the decoherence acting on the probe qubits. We study the evolution of such a tripartite system including the appearance of a decoherence-free state (dark state) and non-Markovian behaviour. We find that all parameters of this TLS can be obtained from measurements of one of the probe qubits. Furthermore we show the advantages of two qubits in probing environments and the new dynamics imposed by a TLS which couples to two qubits at once.