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TT: Fachverband Tiefe Temperaturen

TT 44: Poster Session Correlated Electrons

TT 44.32: Poster

Thursday, March 17, 2011, 10:00–13:00, P1

flow equations approach to one dimensional quantum Ising model — •Amin Kiani¹, Farhad Shahbazi², and Seyed Akbar Jafari³ — ¹Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany — ²Department of physics, Isfahan University of Technology, Isfahan, Iran — ³Department of physics, Sharif University of Technology, Tehran, Iran

One dimensional quantum Ising model with nearest neighbor interaction in transverse magnetic field is one of the simplest spin models which undergoes quantum phase transition. This model has been solved with different methods exactly. In this paper, we solve this model in uniform magnetic field −Jgσ_n^x exactly with new method called Continuous Unitary Transformations (CUT) or Flow equations and obtain the expectation values of ⟨σ_n^x⟩, ⟨σ_n^z⟩ and ⟨σ_n^xσ_n+j^x⟩. Then we apply this method on one dimensional Quantum Ising model in staggered magnetic field (−1)ⁿJgσ_n^x. We observed that both models have the same critical properties as we expected. Moreover we observe that the spontaneous symmetry breaking cannot be derived from CUT.