transverse Ising chain with periodically varying bonds and fields
نویسنده
چکیده
Using continued fractions we study the ground state properties of the spin– 1 2 Ising chain in a transverse field with periodically varying interaction strengths and external fields. We consider in detail the chain having the period of modulation of interactions equals 2 and compare the results obtained with those corresponding to the spin– 1 2 isotropic XY chain in a transverse field. In contrast to the behaviour of the transverse XY chain, the transverse Ising chain does not exhibit a step–like magnetization vs. field dependence caused by the alternation of bonds, its susceptibility exhibits a logarithmic singularity at the field determined by interaction strengths, and it is stable with respect to spin–Peierls dimerization. PACS numbers: 75.10.–b
منابع مشابه
Quantum Phase Transitions in Alternating Transverse Ising Chains
This chapter is devoted to a discussion of quantum phase transitions in regularly alternating spin1 2 Ising chain in a transverse field. After recalling some generally-known topics of the classical (temperature-driven) phase transition theory and some basic concepts of the quantum phase transition theory I pass to the statistical mechanics calculations for a one-dimensional spin1 2 Ising model ...
متن کاملQuantum Spin Chains with Regularly Alternating Bonds and Fields
We consider the spin1 2 XY chain in a transverse field with regularly varying exchange interactions and on-site fields. In two limiting cases of the isotropic (XX) and extremely anisotropic (Ising) exchange interaction the thermodynamic quantities are calculated rigorously with the help of continued fractions. We discuss peculiarities of the low-temperature magnetic properties and a possibility...
متن کاملQuantum phase transitions in alternating transverse Ising chains: Rigorous analytical and exact numerical results
We examine the ground state properties of the s = 1 2 transverse Ising chain with regularly alternating bonds and fields using exact analytical results and exact numerical data for long (up to N = 900) and short (N = 20) chains. For a given period of alternation the system may exhibit a series of quantum phase transitions, where the number of transitions depends on the concrete set of the param...
متن کاملHigh order perturbation study of the frustrated quantum Ising chain
In this paper, using high order perturbative series expansion method, the critical exponents of the order parameter and susceptibility in transition from ferromagnetic to disordered phases for 1D quantum Ising model in transverse field, with ferromagnetic nearest neighbor and anti-ferromagnetic next to nearest neighbor interactions, are calculated. It is found that for small value of the frustr...
متن کاملMagnetic Properties and Phase Transitions in a Spin-1 Random Transverse Ising Model on Simple Cubic Lattice
Within the effective-field theory with correlations (EFT), a transverse random field spin-1 Ising model on the simple cubic (z=6) lattice is studied. The phase diagrams, the behavior of critical points, transverse magnetization, internal energy, magnetic specific heat are obtained numerically and discussed for different values of p the concentration of the random transverse field.
متن کامل