1. Relaxation of the nuclear spin system is crucial for all NMR applications. 2. I know, that nuclear and electron spin systems are the standard example. 3. The number " " is the multiplicity of the spin system . 4. This approach works for distinguishable particles or the spin systems . 5. These results agree with numerous numerical studies of model quantum spin systems in two dimensions. 6. An example of such a component is a spin system within a body, as follows. 7. Let's take the example of nuclear spin systems . 8. It is possible to add energy to the spin system using radio frequency ( RF ) techniques. 9. In systems with a large number of degrees of freedom, like spin systems , Monte Carlo integration is required. 10. This allows NDR to cool the nuclear spin system to very low temperatures, often 1 �K or below.