Researchers have discovered a potential bridge between general relativity and quantum mechanics - two preeminent physical theories - and this could lead physicists to rethink the very nature of space and time.
Albert Einstein's theory of general relativity describes gravity as a geometric property of space and time. The more massive the object, the more its space-time distortion and this distortion is felt as gravity.
In the 1970s, physicists Stephen Hawking and Jacob Beckenstein noted the relationship between the surface area of black holes and their microscopic quantum structure, which determines their entropy. This signified the first realization that there is a connection between general relativity and quantum mechanics, reports vnauke.in.ua
Less than three decades later, the theoretical physicist Juan Maldacena observed another connection between gravity and the quantum world. This relationship has led to the creation of a model that suggests that spacetime can be created or destroyed by varying the amount of entanglement between different surface areas of an object.
In other words, this means that spacetime itself, at least as defined in the models, is a product of intertwining between objects.
To further explore this line of thought, Chungjun Cao and Sean Carroll of California Institute of Technology (CalTech) decided to see if they could actually derive the dynamic properties of gravity (as is known from general relativity) by using a structure in which spacetime emerges from quantum entanglement. Their research was recently published in arXiv.
Using an abstract mathematical concept called Hilbert space, Cao and Carroll were able to find similarities between the equations that govern quantum entanglement and Einstein's equations of general relativity. This confirms the idea that spacetime and gravity arise from entanglement.
“One of the more obvious ones is to test whether the symmetries of relativity are restored in this structure, in particular the idea that the laws of physics are independent of how fast you move through space,” Carroll said.
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The theory of everything
Today, almost everything we know about the physical aspects of our universe can be explained by either general relativity or quantum mechanics. The former does a great job of explaining activity on very large scales, such as planets or galaxies, while the latter helps us understand very small scales, such as atoms and subatomic particles.
However, the two theories seem to be incompatible with each other. This led physicists to seek an elusive "theory of everything" - a single structure that would explain it all, including the nature of space and time.
Since gravity and spacetime are an important part of "everything," Carroll said he believes the research he and Cao has done may help to find a theory that reconciles general relativity and quantum mechanics.
“Our research does not yet talk about other forces of nature, so we are still quite far from 'creating a theory of everything,'” he said.
However, if we could find such a theory, it could help us answer some of the biggest questions facing scientists today. We can finally understand the true nature of dark matter, dark energy, black holes and other mysterious space objects.
Already, researchers are gaining insight into the quantum world’s ability to radically improve our computing systems, and a theory of everything could potentially speed up the process by revealing new perspectives on a still largely confused world.
