In this paper we consider so-called Google matrices and show that all eigenvalues ($lambda$) of them have a fundamental property $|lambda|leq 1$. The stochastic eigenvector corresponding to $lambda=1$ called the PageRank vector plays a central role i
n the Googles software. We study it in detail and present some important problems. The purpose of the paper is to make {bf the heart of Google} clearer for undergraduates.
In this paper we treat coherent-squeezed states of Fock space once more and study some basic properties of them from a geometrical point of view. Since the set of coherent-squeezed states ${ket{alpha, beta} | alpha, beta in fukuso}$ makes a real 4-
dimensional surface in the Fock space ${cal F}$ (which is of course not flat), we can calculate its metric. On the other hand, we know that coherent-squeezed states satisfy the minimal uncertainty of Heisenberg under some condition imposed on the parameter space ${alpha, beta}$, so that we can study the metric from the view point of uncertainty principle. Then we obtain a surprising simple form (at least to us). We also make a brief review on Holonomic Quantum Computation by use of a simple model based on nonlinear Kerr effect and coherent-squeezed operators.
This is a sequel to the paper [K. Fujii : SIGMA {bf 7} (2011), 022, 12 pages]. In this paper we treat a non-Gaussian integral based on a quartic polynomial and make a mathematical experiment by use of MATHEMATICA whether the integral is written in terms of its discriminant or not.
In this paper a geometric method based on Grassmann manifolds and matrix Riccati equations to make hermitian matrices diagonal is presented. We call it Riccati Diagonalization.
In this paper we treat the time evolution of unitary elements in the N level system and consider the reduced dynamics from the unitary group U(N) to flag manifolds of the second type (in our terminology). Then we derive a set of differential equation
s of matrix Riccati types interacting with one another and present an important problem on a nonlinear superposition formula that the Riccati equation satisfies. Our result is a natural generalization of the paper {bf Chaturvedi et al} (arXiv : 0706.0964 [quant-ph]).
