Phase diagram and correlation exponents for quantum spin-1 chain

Toshiya Hikihara, Takashi Tonegawa, Tomotoshi Nishino +8 more

M. Barati, Abdolali Ramazani

The phase diagram and critical exponent of the correlation length for an Ising chain with a long-range interaction in the form of ${1/r}^{1+\ensuremath{\sigma}}$ for $S=1/2,1,3/2,2$ is calculated by the finite-range scaling technique. The spin dependence of the critical temperature and critical exponent $\ensuremath{\nu}$ in the classical and nonclassical regions is also studied. It is observed that, with a good approximation, the critical exponent of the correlation length is independent of the magnitude of spin in both the classical and nonclassical regions.

Kiyoshi Sogo, M. Uchinami

A Monte Carlo method for quantum spin-1 systems is presented. The internal energy and longitudinal correlation functions are computed in the antiferromagnetic region. Some exponents and the phase diagram are derived with good accuracy.

Rodrigo G. Pereira, Steven White, Ian K. Affleck

Jenő Sólyom

Philipp Werner, Matthias Troyer, Subir Sachdev A

We use Monte Carlo simulations to study chains of Ising- and XY-spins with dissipation coupling to the site variables. The phase diagram and critical exponents of the dissipative Ising chain in a transverse magnetic field have been computed previously, and here we consider a universal ratio of susceptibilities. We furthermore present the phase diagram and exponents of the dissipative XY-chain, which exhibits a second order phase transition. All our results compare well with the predictions from a dissipative $ϕ^4$ field theory.