Commenting http://www.wired.com/2014/04/quantum-theory-flow-time/

The problem with physicists is that they often don't look beyond their models of what happens on the micro level. A universe is not a roll of film that could be watched in either direction, because after the universe forms objects on the macro level, these also have an influence.

A very simple universe made of elementary particles has no need for an "arrow of time", but in a more complex universe the arrow of time rises from the complexity itself.

You can't "wind back the time" in our universe. There's no basis in physics for the idea that the flow of time is just a roll of film and that all matter would behave as it did in the past. It would be bizarre if long dead stars whose atoms have been scattered around the galaxy would come back at the moment of their explosion as supernovas and would then start to become younger.

Stars don't behave like that. Complex objects don't behave like that.

Information about the past would also have to be preserved 100 % so that the flow of time could change even in a very simple universe without complexity.