How to pass an object into a state using UI-router?

I'd like to be able to transition to a state and a pass an arbitrary object using ui-router.

I'm aware that usually $stateParams is used, but I believe this value is inserted into the URL, and I don't want users to be able to bookmark this data.

I'd like to do something like this.

$state.transitionTo('newState', {myObj: {foo: 'bar'}});

function myCtrl($stateParams) {
   console.log($stateParams.myObj); // -> {foo: 'bar'}
};

Is there a way to do this without encoding values into the URL?