NMR is routinely used as an indispensable research tool in present-day chemical laboratories because a wide variety of parameters can be extracted from the response of an ensemble of nuclear spins to a resonant excitation. Among them, the chemical shift in nuclear magnetic shielding and the electroncoupled nuclear spin-spin coupling are direct measures of the change in chemical environment arou...

As we saw in Chapter 8, it is difficult to treat the interparticle interactions in a classical many body system of particles. As might be expected, the analysis of the analogous quantum system is even more difficult. Just as we developed the density expansion of a classical gas by doing perturbation theory about the ideal gas, we will first treat an interacting many-body quantum system by start...

We study theoretically the spin response functions using the relativistic many body theory. The spin response functions in the relativistic theory are reduced largely from the ones of the non-relativistic theory. This happens particularly to the longitudinal spin responses. This fact is able to remove the difficulty in reproducing the ratio of the longitudinal and transverse response functions ...

Quantum gravity in an AdS spacetime is described by an SU(N) Yang-Mills theory on a sphere, a bounded many-body system. We argue that in the high temperature phase the theory is intrinsically non-perturbative in the large N limit. At any nonzero value of the ’t Hooft coupling λ, an exponentially large (in N) number of free theory states of wide energy range (or order N) mix under the interactio...

The ratio of double-to-single ionization of He has been measured between 280 eV and 1210 eV to investigate its energy dependence in the intermediate region. The new intermediate energy measurement, compared with the most recent theories of Pan and Kelly and of Hino and Hino et al., show the importance of including not only ground state but also final state correlations. They also appear to indi...