Not sure how new this theory is:
I know Stephen Hawking pimped for it, or one possibility of it, years ago.
8 Shocking Things We Learned From Stephen Hawking's Book | Theoretical Physics & Mysteries of the Universe | Grand Design Book & Cosmology
According to Hawking and Mlodinow, one consequence of the theory of quantum mechanics is that events in the past that were not directly observed did not happen in a definite way.
Instead they happened in all possible ways. This is related to the probabilistic nature of matter and energy revealed by quantum mechanics: Unless forced to choose a particular state by direct interference from an outside observation, things will hover in a state of uncertainty.
For example, if all we know is that a particle traveled from point A to point B, then it is not true that the particle took a definite path and we just don't know what it is. Rather, that particle simultaneously took every possible path connecting the two points.
Yeah, we're still trying to wrap our brains around this.
The authors sum up: "No matter how thorough our observation of the present, the (unobserved) past, like the future, is indefinite and exists only as a spectrum of possibilities."
and the same, but different
If there is any "theory of everything" that can describe the whole universe, it is M theory, according to Hawking and Mlodinow. This model is a version of string theory, which posits that at the tiniest levels all particles are fundamentally little loops of string that vibrate at different frequencies. And, if true, all matter and energy would follow rules derived from the nature of these strings.
"M theory is the only model that has all the properties we think the final theory ought to have," the authors write.
One consequence of this theory is that our universe is not the only one – untold numbers of cousin universes exist with different physical laws and properties.