14,961 research outputs found
Field induced transition of the S=1 antiferromagnetic chain with anisotropy
The ground state magnetization process of the S=1 antiferromagnetic chain
with the easy-axis single-ion anisotropy described by negative is
investigated. It is numerically found that a phase transition between two
different gapless phases occurs at an intermediate magnetic field between the
starting and saturation points of the magnetization for . The
transition is similar to the spin flopping, but it is second-order and not
accompanied with any significant anomalous behaviors in the magnetization
curve. We also present the phase diagrams in the m-D and H-D planes which
reveal a possible re-entrant transition.Comment: 6 pages, Revtex, with 6 eps figures, to appear in Phys. Rev. B (Sep.
1
Metamagnetism of antiferromagnetic XXZ quantum spin chains
The magnetization process of the one-dimensional antiferromagnetic Heisenberg
model with the Ising-like anisotropic exchange interaction is studied by the
exact diagonalization technique. It results in the evidence of the first-order
spin flop transition with a finite magnetization jump in the N\'eel ordered
phase for . It implies that the S=1/2 chain is an exceptional case
where the metamagnetic transition becomes second-order due to large quantum
fluctuations.Comment: 4 pages, Revtex, with 6 eps figure
Three-nucleon interactions: dynamics
A discussion is presented of the dynamics underlying three-body nuclear
forces, with emphasis on changes which occurred over several decades.Comment: Talk given at the FM50 symposium, Tokyo, October 200
A Molecular Line Observation toward Massive Clumps Associated with Infrared Dark Clouds
We have surveyed the N2H+ J=1-0, HC3N J=5-4, CCS J_N=4_3-3_2, NH3 (J, K) =
(1, 1), (2, 2), (3, 3), and CH3OH J=7-6 lines toward the 55 massive clumps
associated with infrared dark clouds by using the Nobeyama Radio Observatory 45
m telescope and the Atacama Submillimeter Telescope Experiment 10 m telescope.
The N2H+, HC3N, and NH3 lines are detected toward most of the objects. On the
other hand, the CCS emission is detected toward none of the objects. The
[CCS]/[N2H+] ratios are found to be mostly lower than unity even in the Spitzer
24 micron dark objects. This suggests that most of the massive clumps are
chemically more evolved than the low-mass starless cores. The CH3OH emission is
detected toward 18 out of 55 objects. All the CH3OH-detected objects are
associated with the Spitzer 24 micron sources, suggesting that star formation
has already started in all the CH3OH-detected objects. The velocity widths of
the CH3OH J_K=7_0-6_0 A+ and 7_{-1}-6_{-1} E lines are broader than those of
N2H+ J=1-0. The CH3OH J_K=7_0-6_0 A+ and 7_{-1}-6_{-1} E lines tend to have
broader linewidth in the MSX dark objects than in the others, the former being
younger or less luminous than the latter. The origin of the broad emission is
discussed in terms of the interaction between an outflow and an ambient cloud.Comment: Accepted to Ap
An investigation of children's peer trust across culture: is the composition of peer trust universal?
The components of children's trust in same-gender peers (trust beliefs, ascribed trustworthiness, and dyadic reciprocal trust) were examined in samples of 8- to 11-year-olds from the UK, Italy, and Japan. Trust was assessed by children's ratings of the extent to which same-gender classmates kept promises and kept secrets. Social relations analyses confirmed that children from each country showed significant: (a) actor variance demonstrating reliable individual differences in trust beliefs, (b) partner variance demonstrating reliable individual differences in ascribed trustworthiness, and (c ) relationship variance demonstrating unique relationships between interaction partners. Cultural differences in trust beliefs and ascribed trustworthiness also emerged and these differences were attributed to the tendency for children from cultures that value societal goals to share personal information with the peer group
Critical exponent in the magnetization curve of quantum spin chains
The ground state magnetization curve around the critical magnetic field
of quantum spin chains with the spin gap is investigated. We propose a size
scaling method to estimate the critical exponent defined as from finite cluster calculation. The applications of the
method to the S=1 antiferromagnetic chain and S=1/2 bond alternating chain lead
to a common conclusion . The same result is derived for both edges
of the magnetization plateau of the S=3/2 antiferromagnetic chain with the
single ion anisotropy.Comment: 4 pages, Revtex, with 4 eps figure
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