10.25560/1261
Cederström, Agneta
Imperial College London
Mathematics
Compromised spin systems and random matrix theory
Imperial College London
2007
Parry, Andrew
2007-04-19
2007-04-19
Doctor of Philosophy (PhD)
10044/1/1261
Random Matrix Theory considers symmetries in the QM energy matrix. The differential geometric implications of matrix groups and their relation to many particle quantum mechanical manifolds is explored. The RMT reduction of phase space is described by co-adjoint orbits on Lie matrix groups. Disorder is identified as a statistical mixture of entangled states. The system' s density matrix eigenvalues remain invariant. The spectrum of eigenvalues in an asymmetric quartic matrix potential is calculated in the unitary ensemble. This measure is interpreted to be indicative of the density of pseudo-particle states in compromised spin systems. The splitting of the spectral density into two or more intervals is taken as some type of phase transition. Finally, the temperature-doping phase diagrams of the ceramic compounds (La,Nd,Eu)2- xSrxCuO4 is partitioned into the three RMT symmetry classes by mapping onto the appearance and disappearance of an NMR/NQR signal.