You can return the state this way:
$state.go($state.$current.parent.self.name, $state.params);
An example:
(function() {
'use strict'
angular.module('app')
.run(Run);
/* @ngInject */
function Run($rootScope, $state) {
$rootScope.back = function() {
$state.go($state.$current.parent.self.name, $state.params);
};
};
})();