The CQT team

Picture taken at the end of April 2010 in "Friedenspark" next to the previous location of the Institute


PhD students

Master students

Bachelor students

Project students (computer lab etc.)

Long-term guests

Abstract: We consider the quantum Ising chain with uniformly distributed random antiferromagnetic couplings (1 ≤ Ji ≤ 2) and uniformly distributed random transverse fields (Γ0 ≤ Γi ≤ 2Γ0) in the presence of a homogeneous longitudinal field, h. Using different numerical techniques (DMRG, combinatorial optimisation and strong disorder RG methods) we explore the phase diagram, which consists of an ordered and a disordered phase. At one end of the transition line (h = 0, Γ0 = 1) there is an infinite disorder quantum fixed point, while at the other end (h = 2,Γ0 = 0) there is a conventional classical random fixed point. Close to this fixed point, for h > 2 and Γ0 > 0 there is a reentrant ordered phase, which is the result of quantum fluctuations through an order through disorder phenomenon.