Spin noise gradient echoes

Spin Echoes

Intense radiofrequency power in the form of pulses is applied to an ensemble of spins in a liquid placed in a large static magnetic Geld H&. The frequency of the pulsed r-f power satisGes the condition for nuclear magnetic resonance, and the pulses last for times which are short compared with the time in which the nutating macroscopic magnetic moment of the entire spin ensemble can decay. After...

Gradient echoes: simplified.

Spin Diffusion Measurements: Spin Echoes in the Presence of a Time Dependent Field Gradient

Pulsed NMR Spin Echoes

Pulsed nuclear magnetic resonance techniques with transverse radiofrequency pulses are used to determine the spin-lattice and spin-spin relaxation times of glycerol and Fe solutions of varying concentrations. The nuclear magnetic moments of flourine and hydrogen are found to be μH+ = (1.408± .008)× 10−26 J/T and μF− = (1.324± .007)× 10−26 J/T, respectively. A negative linear relation in log-log...

Decoherence of spin echoes

We define a quantity, the so-called purity fidelity, which measures the rate of dynamical irreversibility due to decoherence, observed e.g in echo experiments, in the presence of an arbitrary small perturbation of the total (system + environment) Hamiltonian. We derive a linear response formula for the purity fidelity in terms of integrated time correlation functions of the perturbation. Our re...