| Summary: | 碩士 === 中原大學 === 應用物理學系 === 84 === The composite particle representation theory(CPRT) was proposed
by Wu and Feng in early 80's. It was originally proposed as a
microscopic theoretical foundation for the nuclear field theory
[19], and then further developed as a general method of quantum
mechanical many-body problems. This method has been
successfully applied to some quark, nuclear and atomic system[21
][20][22]. For example, the application of the composite
particle representation theory in nuclear structure has shown
the identical results as in that the shell model. This
demonstrated that the composite particle representation theory
is indeed an exact many-body theory. The composite particle
representation is based on the idea that some particles can be
coupled as a cluster called composite particle. Thus, we first
expand the Hilbert space into a composite particle
representation (CPR) space, in which the original degrees of
freedom and the composite particle degrees of freedom are both
included. Then a subspace, which is physically equivalent to
the original space, can be found in this enlarged CPR space.
Since in this physical subspace each cluster appears as an
elementary particle, thus a many- body problems is greatly
simplified. In particular, by applying the CPR, a complicated
many-body problem can be transferred into multisteps of two
composite particle problems. In each step, the number of basic
particles is no more than four. This makes the CPR method a
possibility to solve the heavy atomic system without
encountering the difficulty due to dimension explosion as it
does in the configuration interaction method. It also makes the
many particles system to be solved in high accuracy. In present
work , the composite particle is applied to the atomic systems.
The computational details and the programming for four basic
particles have been worked out. Calculations of Be atom were
carried out.
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