Symmetry-Enhanced Boundary Qubits at Infinite Temperature

Area of Science:

• Condensed Matter Physics
• Quantum Information Science
• Topological Phases of Matter

Background:

• Symmetry-protected topological (SPT) phases possess robust boundary states at zero temperature.
• At finite temperatures, bulk observables typically equilibrate, destroying topological order.

Purpose of the Study:

• To investigate the survival of boundary qubits in SPT phases at high temperatures.
• To identify conditions for long-lived coherent qubits in disordered-free systems.

Main Methods:

• Theoretical prediction of parametric regimes for qubit survival.
• Dual picture analysis involving Z_{2}×Z_{2} domain walls.
• Exact diagonalization to confirm long coherence times.
• Proposal and analysis of a Rydberg optical-tweezer array implementation.

Main Results:

• Boundary qubits can persist at arbitrarily high temperatures with exponentially enhanced coherence times compared to the bulk.
• Qubit persistence is linked to the bulk's inability to absorb emitted virtual Z_{2}×Z_{2} domain walls.
• Existence of a pair of conjugate almost strong zero modes correlates with long coherence times.

Conclusions:

• A pathway to experimentally realize long-lived coherent boundary qubits at infinite temperature is provided.
• Rydberg optical-tweezer arrays offer a viable platform for demonstrating these phenomena.
• Distinguishable differences between edge and bulk spin autocorrelators can be observed on relevant timescales.