8,523 research outputs found
Quantum phase transitions in the J-J' Heisenberg and XY spin-1/2 antiferromagnets on square lattice: Finite-size scaling analysis
We investigate the critical parameters of an order-disorder quantum phase
transitions in the spin-1/2 Heisenberg and XY antiferromagnets on square
lattice. Basing on the excitation gaps calculated by exact diagonalization
technique for systems up to 32 spins and finite-size scaling analysis we
estimate the critical couplings and exponents of the correlation length for
both models. Our analysis confirms the universal critical behavior of these
quantum phase transitions: They belong to 3D O(3) and 3D O(2) universality
classes, respectively.Comment: 7 pages, 3 figure
Effects of low level, low frequency electric fields on human reaction time
Low level, low frequency electric field effects on human reaction tim
Numerical Studies of the two-leg Hubbard ladder
The Hubbard model on a two-leg ladder structure has been studied by a
combination of series expansions at T=0 and the density-matrix renormalization
group. We report results for the ground state energy and spin-gap
at half-filling, as well as dispersion curves for one and two-hole
excitations. For small both and show a dramatic drop near
, which becomes more gradual for larger . This
represents a crossover from a "band insulator" phase to a strongly correlated
spin liquid. The lowest-lying two-hole state rapidly becomes strongly bound as
increases, indicating the possibility that phase separation may
occur. The various features are collected in a "phase diagram" for the model.Comment: 10 figures, revte
Electrochemical Data, Part IV Quarterly Report, Jul. 1 - Sep. 30, 1966
Electrolytic equivalent conductance values of hydrochloric aci
Electrochemical data. Part 12 - Electrolytic conductivity of aqueous solutions of the sodium halides
Electrolytic conductivity of aqueous solutions of sodium halide
Electrochemical Data, Part V Quarterly Report, Oct. 1 - Dec. 31, 1966
Electrolytic conductance of hydriodic aci
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