Evolution of multiple quantum coherences with scaled dipolar Hamiltonian.

Area of Science:

• Quantum physics
• Magnetic resonance spectroscopy
• Spin dynamics

Background:

• Correlated spin states exhibit complex dynamics governed by Hamiltonians.
• Monitoring multiple quantum coherences is crucial for understanding spin system evolution.
• Previous methods like the Proportionally Refocused Loschmidt echo (PRL echo) have limitations.

Purpose of the Study:

• To introduce a novel pulse sequence for monitoring multiple quantum coherences distribution.
• To verify the accuracy of weighted coherent quantum dynamics in scaled dipolar Hamiltonians.
• To analyze the evolution of correlated spin states under varying scaling factors.

Main Methods:

• Modification of the Proportionally Refocused Loschmidt echo (PRL echo) pulse sequence with phase increment.
• Experimental application with different scaling factors of the dipolar Hamiltonian.
• Analysis of total magnetization, multiple quantum coherence orders, and spin cluster development over time.

Main Results:

• A strong dependence between the evolution rate and the weighting factor was observed.
• All experimental data exhibited a single, universal trend when plotted against a new time scale, 'self-time'.
• The spin system's quantum evolution remained consistent, with its rate inversely proportional to the scaling factor.

Conclusions:

• The developed pulse sequence effectively monitors multiple quantum coherences in correlated spin states.
• The concept of 'self-time' unifies the observed quantum evolution across different scaling factors.
• The new pulse sequence demonstrates high performance and accuracy in characterizing spin dynamics.