Universal large-order asymptotic behavior of the strong-coupling and high-temperature series expansions

Abstract

For theories that exhibit second-order phase transition, we conjecture that the large-order asymptotic behavior of the strong-coupling (high-temperature) series expansion takes the form σnnb where b is a universal parameter. The associated critical exponent is then given by b þ 1. The series itself can be approximated by the hypergeometric approximants pFp−1 which can mimic the same large-order behavior of the given series. Near the tip of the branch cut, the hypergeometric function pFp−1 has a power-law behavior from which the critical exponent and critical coupling can be extracted. We test the conjecture in this work for the perturbation series of the ground state energy of the Yang-Lee model as a strong-coupling form of the PT -symmetric iϕ3 theory and the high-temperature expansion within the Ising model. From the known b parameter for the Yang-Lee model, we obtain the exact critical exponents, which reflects the universality of b. Very accurate prediction for b has been obtained from the many orders available for the high-temperature series expansion of the Ising model, which in turn predicts accurate critical exponents. Apart from critical exponents, the hypergeometric approximants for the Yang-Lee model show almost exact predictions for the ground state energy from low orders of perturbation series as input.