We characterize the phase diagram of anisotropic Heisenberg spin glasses, finding both the spin and the chiral glass transition. We remark on the presence of strong finite-size effects in the chiral sector. On the spin glass sector, we find that the universality class is that of Ising spin glasses. Our data are compatible with a unique phase transition for the chiral and spin glass sector. We focus on keeping finite-size effects under control, and we stress that they are important to understand experiments. Thanks to large GPU clusters we have been able to thermalize cubic lattices with up to ${64}^{3}$ spins, over a vast range of temperatures (hence, of relaxation times).We characterize the phase diagram of anisotropic Heisenberg spin glasses, finding both the spin and the chiral glass transition. We remark on the presence of strong finite-size effects in the chiral sector. On the spin glass sector, we find that the universality class is that of Ising spin glasses. Our data are compatible with a unique phase transition for the chiral and spin glass sector. We focus on keeping finite-size effects under control, and we stress that they are important to understand experiments. Thanks to large GPU clusters we have been able to thermalize cubic lattices with up to ${64}^{3}$ spins, over a vast range of temperatures (hence, of relaxation times).

arXiv:1309.1599Physical Review BJan 21, 201432 citations

Phase transitions in spin glasses

A. P. Young

Journal of Magnetism and Magnetic MaterialsNov 21, 20064 citations

Absence of an Equilibrium Ferromagnetic Spin-Glass Phase in Three Dimensions

Florent Krząkała, Olivier Martin

Using ground state computations, we study the transition from a spin glass to a ferromagnet in 3D spin glasses when changing the mean value of the spin-spin interaction. We find good evidence for replica symmetry breaking up until the critical value where ferromagnetic ordering sets in, and no ferromagnetic spin glass phase. This phase diagram is in conflict with the droplet/scaling and mean field theories of spin glasses. We also find that the exponents of the second order ferromagnetic transition do not depend on the microscopic Hamiltonian, suggesting universality of this transition.Using ground state computations, we study the transition from a spin glass to a ferromagnet in 3D spin glasses when changing the mean value of the spin-spin interaction. We find good evidence for replica symmetry breaking up until the critical value where ferromagnetic ordering sets in, and no ferromagnetic spin glass phase. This phase diagram is in conflict with the droplet/scaling and mean field theories of spin glasses. We also find that the exponents of the second order ferromagnetic transition do not depend on the microscopic Hamiltonian, suggesting universality of this transition.

arXiv:cond-mat/0208566Physical Review LettersDec 9, 200212 citations

Optically controlled spin-glasses generated using multi-qubit cavity systems

Chiu Fan Lee, Neil F. Johnson

Recent advances in nanofabrication and optical control imply that multi-qubit-cavity systems can now be engineered with pre-designed couplings. Here we propose optical realizations of spin-glass systems which exploit these new nanoscale technologies. By contrast with traditional realizations using magnetic solids, phase transition phenomena can now arise in both the matter and radiation subsystems. Moreover the phase transitions are tunable simply by varying the matter-radiation coupling strength.Recent advances in nanofabrication and optical control imply that multi-qubit-cavity systems can now be engineered with pre-designed couplings. Here we propose optical realizations of spin-glass systems which exploit these new nanoscale technologies. By contrast with traditional realizations using magnetic solids, phase transition phenomena can now arise in both the matter and radiation subsystems. Moreover the phase transitions are tunable simply by varying the matter-radiation coupling strength.

arXiv:quant-ph/0412069Dec 8, 20040 citations

Quantum Phase Transitions in Spin-Lattice Systems

MANFRED L. RISTIG, Khaled Abu Qasem, DAMIAN J. J. FARNELL

Jan 1, 20010 citations

{64}^{3}

spins, over a vast range of temperatures (hence, of relaxation times).