Quantum Phase Transitions in Alternating Transverse Ising Chains
نویسندگان
چکیده
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 in a transverse field, which is the simplest possible system exhibiting the continuous quantum phase transition. The essential tool for these calculations is the Jordan-Wigner fermionization. The latter technique being completed by the continued fraction approach permits to obtain analytically the thermodynamic quantities for a “slightly complicated” model in which the intersite exchange interactions and on-site fields vary regularly along a chain. Rigorous analytical results for the ground-state and thermodynamic quantities, as well as exact numerical data for the spin correlations computed for long chains (up to a few thousand sites) demonstrate how the regularly alternating bonds/fields effect the quantum phase transition. I discuss in detail the case of period 2, swiftly sketch the case of period 3 and finally summarize emphasizing the effects of periodically modulated Hamiltonian parameters on quantum phase transitions in the transverse Ising chain and in some related models.
منابع مشابه
Quantum 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 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 کاملIsing Chain in Regularly Alternating Transverse Field: Spin Correlation Functions
We consider the spin1 2 Ising chain in a regularly alternating transverse field to examine the effects of regular alternation on the quantum phase transition inherent in the quantum Ising chain. The number of quantum phase transition points strongly depends on the specific set of the Hamiltonian parameters but never exceeds 2p where p is the period of alternation. Calculating the spin correlati...
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 کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2004