Quantum spin chains with alternation.

Abstract

Affleck has made predictions for the critical exponents of a class of integrable spin chains of general spin $s$. The expressions are $s$ dependent. Our interest here is a finite-size scaling analysis of spin-1 systems to determine the validity of the prediction for the alternation critical exponent. We discuss these results in the light of our numerical results for the conformal anomaly $c$, the exponent $\ensuremath{\eta}$, and the mass-gap exponent associated with biquadratic exchange. The numerical results are not generally in good agreement with theory, and hence the possible presence of logarithmic corrections is discussed.