13,294 research outputs found
Some Recent Results on Pair Correlation Functions and Susceptibilities in Exactly Solvable Models
Using detailed exact results on pair-correlation functions of Z-invariant
Ising models, we can write and run algorithms of polynomial complexity to
obtain wavevector-dependent susceptibilities for a variety of Ising systems.
Reviewing recent work we compare various periodic and quasiperiodic models,
where the couplings and/or the lattice may be aperiodic, and where the Ising
couplings may be either ferromagnetic, or antiferromagnetic, or of mixed sign.
We present some of our results on the square-lattice fully-frustrated Ising
model. Finally, we make a few remarks on our recent works on the pentagrid
Ising model and on overlapping unit cells in three dimensions and how these
works can be utilized once more detailed results for pair correlations in,
e.g., the eight-vertex model or the chiral Potts model or even
three-dimensional Yang-Baxter integrable models become available.Comment: LaTeX2e using iopart.cls, 10 pages, 5 figures (5 eps files), Dunk
Island conference in honor of 60th birthday of A.J. Guttman
On Dalgarno and Lewis Perturbation Theory for Scattering States
We apply the method of Dalgarno and Lewis to scattering states and discuss
the choice of the unperturbed model in order to have a convergent perturbation
series for the phase shift.Comment: 10 pages, 2 figure
Quantum Loop Subalgebra and Eigenvectors of the Superintegrable Chiral Potts Transfer Matrices
It has been shown in earlier works that for Q=0 and L a multiple of N, the
ground state sector eigenspace of the superintegrable tau_2(t_q) model is
highly degenerate and is generated by a quantum loop algebra L(sl_2).
Furthermore, this loop algebra can be decomposed into r=(N-1)L/N simple sl_2
algebras. For Q not equal 0, we shall show here that the corresponding
eigenspace of tau_2(t_q) is still highly degenerate, but splits into two
spaces, each containing 2^{r-1} independent eigenvectors. The generators for
the sl_2 subalgebras, and also for the quantum loop subalgebra, are given
generalizing those in the Q=0 case. However, the Serre relations for the
generators of the loop subalgebra are only proven for some states, tested on
small systems and conjectured otherwise. Assuming their validity we construct
the eigenvectors of the Q not equal 0 ground state sectors for the transfer
matrix of the superintegrable chiral Potts model.Comment: LaTeX 2E document, using iopart.cls with iopams packages. 28 pages,
uses eufb10 and eurm10 fonts. Typeset twice! Version 2: Details added,
improvements and minor corrections made, erratum to paper 2 included. Version
3: Small paragraph added in introductio
Correlation functions for the three state superintegrable chiral Potts spin chain of finite lengths
We compute the correlation functions of the three state superintegrable
chiral Potts spin chain for chains of length 3,4,5. From these results we
present conjectures for the form of the nearest neighbor correlation function.Comment: 10 pages; references update
Q-Dependent Susceptibilities in Ferromagnetic Quasiperiodic Z-Invariant Ising Models
We study the q-dependent susceptibility chi(q) of a series of quasiperiodic
Ising models on the square lattice. Several different kinds of aperiodic
sequences of couplings are studied, including the Fibonacci and silver-mean
sequences. Some identities and theorems are generalized and simpler derivations
are presented. We find that the q-dependent susceptibilities are periodic, with
the commensurate peaks of chi(q) located at the same positions as for the
regular Ising models. Hence, incommensurate everywhere-dense peaks can only
occur in cases with mixed ferromagnetic-antiferromagnetic interactions or if
the underlying lattice is aperiodic. For mixed-interaction models the positions
of the peaks depend strongly on the aperiodic sequence chosen.Comment: LaTeX2e, 26 pages, 9 figures (27 eps files). v2: Misprints correcte
Systematic description and key to isolants from Atacama Desert, Chile
Isolation and identification of desert soil microorganism from Chil
Properties of the ground F state and the excited P state of atomic thorium in cold collisions with He
We measure inelastic collisional cross sections for the ground F
state and the excited P state of atomic thorium in cold collisions with
He. We determine for Th (F) at 800 mK the ratio of the momentum-transfer to Zeeman relaxation cross sections for
collisions with He. For Th (P), we study electronic inelastic
processes and find no quenching even after collisions. We also determine
the radiative lifetime of Th (P) to be ms. This great
stability of the metastable state opens up the possibility for further study,
including trapping
Vibrational quenching of the electronic ground state in ThO in cold collisions with He
We measure the ratio of the momentum-transfer to the vibrational
quenching cross section for the X (), , state
of molecular thorium monoxide (ThO) in collisions with atomic He between
800 mK and 2.4 K. We observe indirect evidence for ThO--He van der Waals'
complex formation, which has been predicted by theory. We determine the 3-body
recombination rate constant at 2.4 K, and establish that the binding
energy E 4 K
A qualitative case study of ethnic Chinese instrumental music teachers’ perceptions of teacher identity and status at an international school in Hong Kong
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