Quantum Gravity Coming Soon… Maybe.
Don’t like quantum mechanics? Don’t worry Einstein didn’t either. In fact, not only did Einstein not like quantum mechanics, neither did his general theory of relativity. Which was okay… sort of. Quantum mechanics involves things that are really small, while relativity dealt with things that are really large and never the two shall meet, that is, until they do.
It’s not Einsteins fault that the two theories don’t play well together. They are both mathematical formulas, there is no malice involved. Einsteins world was beautiful and solid, he wanted to use math to form a world made of granite, smooth, shiny and perfect. Quantum mechanics on the other hand is uncertain, that is a fundamental principle, it’s more like wood, it’s not pretty, rough and textured.
Since the birth of quantum mechanics about 80 years ago scientists have been pulling their hair and beating their heads against walls trying to solve the problem. Why bother? Well because in certain cases you need both, like when you have something where gravity comes into effect but is still incredibly small. Like a black hole for example, or more importantly [in my mind] the birth of the universe.
Yet another problem, without solving the issue you will never be able to create a unified theory of everything. The mathematical formula that governs everything in the universe, it would be to science, what god is to religion, the key to everything.
There is a promising contender to unify the two, called the AdS/CFT correspondence. I won’t bother to bombard you with the details since the theory is very complex [and why wouldn’t it be, we are talking gravity and quantum mechanics]. It says that for every two dimensional [or any dimensional] CFT [which stands for conformal field theory and just explains how a field, like a magnetic field might act over time in a certain space] there would be a corresponding three dimensional theory of gravity [or CFT +1 the +1 being a dimension for gravity].
It sounds perfect and on paper it works out great when it is used to solve problems. In fact it’s been used to solve some of the hardest problems that physicists have been batting around. But there is a catch…
While it works, there is no proof to show that it actually works, meaning you can’t go from AdS/CFT and pull out quantum mechanics and relativity. So there is no proof that it actually works and it is not just getting ‘lucky’ with it’s answers.
That all might be changing, thanks to a condensed matter physicist. He is proposing a new piece of math called the quantum renormalization group. What it does is act like a scale on a map or a zoom on a camera. It allows you to zoom into the molecules to see [mathematically] the way they move or zoom out and watch the whole object act.
Normally that would just be called a renormalization group, a quantum renormalization group works in the same manner but is a little more ‘fuzzy’ sort of like quantum mechanics. Which might sound that you can’t prove it works, but just like quantum mechanics, you can infact show proof that it holds true for any case.
Will this be the breakthrough physicists have been dreaming about? It’s hard to say, but as Sung-Sik Lee, the physicist who is tackling this project says:
“Quantum systems can do strange things. If we are to truly understand them, we need to make our theory stranger, too.”
Already know your eigenvalues from your coupling constants? Then you probably want something a little more technical, you can find the original press release — here!
Lee S.S. (2014). MAPPING THE ROAD TO QUANTUM GRAVITY, Perimeter Institute for Theoretical Physics, Other: Link