Brane vacuum as chain of rotators

We analyse the noncommutative U(1) sigma model, which arises from the conjecture that the tachyonic mode in non-stable brane system is composite. The sector of spherically symmetric'' excitations of the model is equivalent to a chain of rotators. Classical solutions for this model are found, which are static and spherically symmetric'' in noncommutative spatial dimensions. The limit of small noncommutativity reveals the presence of Polyakov vortices in the model. A generalisation of the model to q-deformed space, which may serve as a regularisation of the non-deformed model is also considered. (author)