New Universality Class in the S=1/2 Fibonacci Heisenberg Chains
  Low energy properties of the S=1/2 antiferromagnetic Heisenberg chains with Fibonacci exchange modulation are studied using the real space renormalization group method for strong exchange modulation. It is found that the ground state of this model belongs to a new universality class with logarithmically divergent dynamical exponent which is neither like Fibonacci XY chains nor like XY chains with relevant aperiodicity. 
Kazuo Hida