Extending the electron spin coherence time of atomic hydrogen by dynamical decoupling

Area of Science:

• Quantum physics
• Materials science
• Chemistry

Background:

• Electron spin decoherence limits quantum information processing.
• Encapsulated atomic hydrogen in octasilsesquioxane cages offers a model system for studying spin dynamics.
• Nuclear spin baths can significantly impact electron spin coherence.

Purpose of the Study:

• To investigate the sources of electron spin decoherence for encapsulated atomic hydrogen.
• To quantify the decoherence effects induced by the (1)H and (29)Si nuclear spin bath.
• To explore the utility of dynamical decoupling techniques in mitigating decoherence.

Main Methods:

• Utilized the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence for dynamical decoupling.
• Applied CPMG to suppress low-frequency noise from nuclear spin flip-flops.
• Analyzed decoherence mechanisms including classical magnetic field noise and anisotropic hyperfine coupling.

Main Results:

• Achieved a maximum spin coherence time (T2) of 56 μs by suppressing low-frequency noise.
• Identified classical magnetic field noise from (1)H nuclear spins of cage substituents.
• Revealed decoherence due to anisotropic hyperfine coupling with inner (29)Si spins.

Conclusions:

• Dynamical decoupling effectively suppresses certain decoherence sources in encapsulated atomic hydrogen.
• Two primary decoherence mechanisms beyond nuclear spin bath flip-flops were identified.
• Understanding these decoherence pathways is crucial for advancing quantum applications using such systems.