2023/12/20 by Fava, Michele, Jacobsen, Jesper Lykke, Nahum, Adam
#Disordered Systems and Neural Networks (cond-mat.dis-nn) #FOS: Physical sciences #Statistical Mechanics (cond-mat.stat-mech) #Strongly Correlated Electrons (cond-mat.str-el)
paper · doi:10.48550/arxiv.2312.13452
We study the 1D quantum Heisenberg chain with randomly ferromagnetic or antiferromagnetic couplings (a model previously studied by approximate strong-disorder RG). We find that, at least for sufficiently large spin S, the ground state has ``spin glass'' order. The spin waves on top of this state have the dynamical exponent z=3/2, intermediate between the values z=1 of the antiferromagnet and z=2 of the ferromagnet. DMRG simulations are in good agreement with the analytical results for spins S=1 and S=3/2. The case S=1/2 shows large finite size effects: we suggest that this case is also ordered, but with a small ordered moment.