New model Hamiltonian with four-spin interactions: Phase diagram and formation of domains and walls

1983 ◽  
Vol 28 (7) ◽  
pp. 4001-4005 ◽  
Author(s):  
Santiago D'Elía ◽  
Horacio Ceva
Keyword(s):  
Phase Diagram ◽  
New Model ◽  
Spin Interactions ◽  
Model Hamiltonian

T = 0 phase diagram of the 1D Hubbard model with magnetic interactions in the narrow band limit

Open Physics ◽  
2012 ◽  
Vol 10 (3) ◽  
Author(s):  
Ferdinando Mancini ◽  
Evgeny Plekhanov ◽  
Gerardo Sica
Keyword(s):  
Phase Diagram ◽  
Hubbard Model ◽  
Narrow Band ◽  
Operator Method ◽  
Magnetic Interactions ◽  
Exchange Constant ◽  
Local Charge ◽  
Spin Interactions ◽  
Charge Interaction ◽  
Composite Operator Method

AbstractIn this paper we study a generalization of the Hubbard model by considering spin-spin interactions described by the exchange constant J. An external magnetic field his also taken into account. In the narrowband limit and for the 1D case, we present the exact solution obtained in the framework of the Green’s function formalism, using the Composite Operator Method. We report the T = 0 phase diagram for both ferro (J > 0) and anti-ferro (J < 0) couplings. The competition of the different energy scales (U, J, and h; being U the local charge interaction) generates a variety of phases and different charge and spin orderings.

scholarly journals Phase diagram for a cubic-Qinteracting boson model Hamiltonian: Signs of triaxiality

2011 ◽  
Vol 84 (1) ◽  
Author(s):  
L. Fortunato ◽  
C. E. Alonso ◽  
J. M. Arias ◽  
J. E. García-Ramos ◽  
A. Vitturi
Keyword(s):  
Phase Diagram ◽  
Model Hamiltonian ◽  
Boson Model

PHASE DIAGRAMS OF VARIOUS KINDS OF ISING SPIN-GLASS MODELS WITH A NEW PARAMETER TO CONTROL FRUSTRATION ON A GIVEN LATTICE

2010 ◽  
Vol 24 (05) ◽  
pp. 567-573 ◽  
Author(s):  
YOUICHIRO HASHIZUME ◽  
XIAO HU ◽  
MASUO SUZUKI
Keyword(s):  
Phase Diagram ◽  
Spin Glass ◽  
Effective Field ◽  
Continuous Control ◽  
Continuous Change ◽  
Many Body ◽  
Ising Spin ◽  
Spin Interactions ◽  
Transition Points

In this study, we introduce a new method to control continuously the frustration caused by the quenched interaction in a given lattice, and we examine how the phenomenon changes by continuous control of the frustration, especially examining a continuous change of phase transition points. For this purpose, we introduce many-body correlation among original spin-interactions using a distribution function to express the correlations, which plays a role of a parameter to control the frustration. The transition points have been obtained by the cluster effective field theory. As a result, an interesting phase diagram has been obtained for the continuous change of frustration. Furthermore, phase transitions of various models can be analyzed systematically in a fixed lattice from this phase diagram with a variable of continuous change of frustration. In addition, it is understood that the spin-glass transition points do not depend on the disorder of the interaction and are decided only by the frustration.

New Model Hamiltonian for the Metal-Insulator Transition

1979 ◽  
Vol 43 (26) ◽  
pp. 1957-1960 ◽  
Author(s):  
C. Castellani ◽  
C. Di Castro ◽  
D. Feinberg ◽  
J. Ranninger
Keyword(s):  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
New Model ◽  
Model Hamiltonian

scholarly journals Spin-Phonon Chains with Bond Coupling

2019 ◽  
Author(s):  
Rainer Kühne
Keyword(s):  
Phase Transition ◽  
Phase Diagram ◽  
Magnetic Susceptibility ◽  
Quantum Monte Carlo ◽  
Flow Equation ◽  
Spin Model ◽  
Heisenberg Chain ◽  
Temperature Dependent ◽  
Effective Spin ◽  
Spin Interactions

We investigate the antiadiabatic limit of an antiferromagnetic S=1/2 Heisenberg chain coupled to Einstein phonons via a bond coupling. The flow equation method is used to decouple the spin and the phonon part of the Hamiltonian. In the effective spin model longer range spin-spin interactions are generated. The effective spin chain is frustrated. The resulting temperature dependent couplings are used to determine the magnetic susceptibility and to determine the phase transition from a gapless state to a dimerized gapped phase. The susceptibilities and the phase diagram obtained via the effective couplings are compared with independently calculated quantum Monte Carlo results.

The Hitachi Model HS-8 Electron Microscope

1967 ◽  
Vol 25 ◽  
pp. 238-239
Author(s):  
H. Akabori ◽  
K. Nishiwaki ◽  
K. Yoneta
Keyword(s):  
Electron Microscope ◽  
New Model ◽  
Predecessor Model

By improving the predecessor Model HS- 7 electron microscope for the purpose of easier operation, we have recently completed new Model HS-8 electron microscope featuring higher performance and ease of operation.

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