Entanglement and decoherence in near-critical qubit chains

TL;DR

This paper investigates how environmental decoherence affects entanglement in large, near-critical qubit chains, revealing a trade-off between entanglement and decoherence that challenges quantum processor design.

Contribution

It identifies decoherence rates in near-critical qubit chains using Jordan-Wigner fermion representation, highlighting the conflicting requirements for entanglement and decoherence management.

Findings

Decoherence rates increase near criticality.

Massive shared entanglement is associated with higher decoherence.

Designs must balance entanglement benefits against decoherence drawbacks.

Abstract

We study the problem of environmentally-induced decoherence in a near-critical one-dimensional system of N>>1 coupled qubits. Using the Jordan-Wigner fermion representation of the qubit operators we identify the decoherence rates relevant for the two-qubit reduced density matrix. We find that a desirable onset of massive shared entanglement in the near-critical regime comes at the expense of decoherence which also tends to increase as the system is tuned towards criticality. Our results reveal rather contradictory general requirements that future designs of a qubit chain-based quantum information processor will need to satisfy.