Long-lived polarization protected by symmetry.

Area of Science:

• Nuclear Magnetic Resonance (NMR) Spectroscopy
• Quantum Information Science
• Molecular Biophysics

Background:

• Long-lived spin polarization is crucial for enhancing sensitivity in NMR spectroscopy.
• Symmetry-based approaches offer a promising route to stabilize spin polarization.
• Existing methods for generating long-lived states are often limited in scope or efficiency.

Purpose of the Study:

• To theoretically and experimentally elucidate molecular motifs for Long-Lived Polarization Protected by Symmetry (LOLIPOPS).
• To explore the scalability and applicability of LOLIPOPS across different spin system sizes.
• To provide a comprehensive understanding of the symmetry, creation, and manipulation of LOLIPOPS.

Main Methods:

• Theoretical analysis using group theory for six-spin systems.
• Experimental realization and characterization of four-spin LOLIPOPS.
• Computational simulations to explore eight-spin systems.
• Development and application of specific pulse sequences for state manipulation.

Main Results:

• Demonstrated the creation of LOLIPOPS from pairs of chemically equivalent nuclei coupled to additional spins.
• Analyzed the symmetry properties of accessed states in various spin systems (AA'XnX'n).
• Quantified the polarization storage capacity and pathways for accessing protected states from (15)N, (13)C, or proton polarization.

Conclusions:

• LOLIPOPS provide a robust method for generating and storing long-lived nuclear spin polarization.
• The described principles are applicable to various spin system sizes, offering scalability.
• This work advances NMR techniques by enabling enhanced sensitivity and novel applications through controlled polarization storage.