A variational solution to solitons in parity-time symmetric optical lattices

. A variational technique is established to study the fundamental solitons in parity-time symmetric optical lattices. The variational results show that the fundamental solitons can exist in the semi-infinite gap. The variational method can be fit for the solitons whose real part of field is symmetrical or antisymmetrical. Following numerical simulations, the variational results are in good agreement with the numerical results.