Algebraic Bethe ansatz for U_q(so(2n))- and U_q(sp(2n))-symmetric spin chains

Vidas Regelskis (University of Hertfordshire and Vilnius University) will offer a seminar in Integrable Systems.

The algebraic Bethe ansatz has been very fruitful in the study of gl(n)-symmetric integrable models. The study of the so(n)- and sp(n)-symmetric models so far has been less productive. One of the obstacles is that the R-matrix in this case is not quite of a six-vertex type, which is the key property used in the study of the gl(n)-symmetric models. Another obstacle is that not every irreducible highest weight so(n)- or sp(n)-representation can be lifted to a representation of the corresponding quantum group, such as Yangian or quantum loop algebra. 

The algebraic Bethe ansatz for so(n)- and sp(n)-symmetric periodic spin chains in the rational setting has been presented by De Vega and Karowski and Reshetikhin back in 80’s. 30 years later I will explain how their ideas can be lifted to the trigonometric setting.