Quantum renormalization group for the xxz model in the presence of an external magnetic field

Ioannis N. Velonakis

J. Ricardo de Sousa, N. S. Branco, B. Boechat +1 more

Vieri Mastropietro

Pradeep K. Thakur, P. Durganandini

We study the interplay of electric and magnetic order in the one-dimensional Heisenberg spin-$\frac{1}{2}$ XXZ chain with large Ising anisotropy in the presence of the Dzyaloshinskii-Moriya (DM) interaction and with longitudinal and transverse magnetic fields, interpreting the DM interaction as a coupling between the local electric polarization and an external electric field. We obtain the ground state phase diagram using the density matrix renormalization group method and compute various ground state quantities like the magnetization, staggered magnetization, electric polarization and spin correlation functions, etc. In the presence of both longitudinal and transverse magnetic fields, there are three different phases corresponding to a gapped N\'eel phase with antiferromagnetic (AF) order, gapped saturated phase, and a critical incommensurate gapless phase. The external electric field modifies the phase boundaries but does not lead to any new phases. Both external magnetic fields and electric fields can be used to tune between the phases. We also show that the transverse magnetic field induces a vector chiral order in the N\'eel phase (even in the absence of an electric field) which can be interpreted as an electric polarization in a direction parallel to the AF order.

Georges Collince Fouokeng, I Nsangou, F. Kuate Fodouop +2 more

Abstract The dynamical dephasing of a bipartite and tripartite quantum coherence in spin-1/2 Heisenberg model, driven by an applied magnetic field, in the presence of Dzyaloshinskii-Moriya interaction is investigated. The system is renormalized through the Kadanoof’s blocks approach. It is observed for both bipartite and tripartite schemes that by increasing the size of the system, the quantum coherence measure show an abrupt change at a quantum critical point (QCP). A further increase of the Dzyaloshinskii-Moriya coupling parameter affect the QCP, causing the dynamical dephasing which is the signature of second order quantum phase transition. The displacement of the QCP reduces the Quantum coherence of the system and can be controlled by the external magnetic field strength. Moreover, in a given range of Dzyaloshinskii-Moriya interaction strength and magnetic field, the monogamous and polygamous nature of quantum coherence is related to the size of the system.

I. Golhirsch, Evgeny Levich, Victor Yakhot