149,849 research outputs found
A study of the research done on the gifted child from 1952 to the present day.
Thesis (Ed.M.)--Boston Universit
The origin of order in random matrices with symmetries
From Noether's theorem we know symmetries lead to conservation laws. What is
left to nature is the ordering of conserved quantities; for example, the
quantum numbers of the ground state. In physical systems the ground state is
generally associated with `low' quantum numbers and symmetric, low-dimensional
irreps, but there is no \textit{a priori} reason to expect this. By
constructing random matrices with nontrivial point-group symmetries, I find the
ground state is always dominated by extremal low-dimensional irreps. Going
further, I suggest this explains the dominance of J=0 g.s. even for random
two-body interactions.Comment: 5 figures; contribution to "Beauty in Physics" conference in honor of
Francesco Iachello, May 2012, Cocoyoc, Mexic
Tracing the evolution of nuclear forces under the similarity renormalization group
I examine the evolution of nuclear forces under the similarity
renormalization group (SRG) using traces of the many-body configuration-space
Hamiltonian. While SRG is often said to "soften" the nuclear interaction, I
provide numerical examples which paint a complementary point of view: the
primary effect of SRG, using the kinetic energy as the generator of the
evolution, is to shift downward the diagonal matrix elements in the model
space, while the off-diagonal elements undergo significantly smaller changes.
By employing traces, I argue that this is a very natural outcome as one
diagonalizes a matrix, and helps one to understand the success of SRG.Comment: 6 pages, 3 figures, 1 tabl
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