Physicists in Australia claim to have simulated time travel using fairly standard optical equipment on a lab bench. They say they have prepared photons that behave as if they are travelling along short cuts in space–time known as "closed time-like curves", and add that their work might help in the long-sought-after unification of quantum mechanics and gravity. Others, however, argue that the research does little or nothing to establish whether time travel is possible in nature.
Although everyday experience suggests the impossibility of travelling backwards or forwards in time, Einstein's general theory of relativity does not rule it out. The theory allows for loops in space–time called closed time-like curves that could be created by very powerful sources of gravity such as black holes. These structures would bring an object back to a place and a time that it had already passed through, typically via a short cut between the two separated regions of space–time known as a wormhole.
To read more, click here.