The Loop Quantum Gravity as I heard states that there are indivisible chunks of space and time in the space-time fabric and therefore it is possible for an object to occupy least possible space and that there can be a simplest time for events to take place. This theory is said to explain Quantum Gravity, but I failed to understand how?

**I dont know why this question was closed and marked as unclear?"

  • $\begingroup$ @Qmechanic you have edited in the wiki link which shows the misunderstanding of the questioner in the first paragraph. You should either have made it an answer or a comment. $\endgroup$ – anna v Jun 12 '17 at 13:36
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    $\begingroup$ Your question is answered if you read the link proviced by the editing by Qmechanic $\endgroup$ – anna v Jun 12 '17 at 13:37
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    $\begingroup$ Hi Ajinkya Naik: Welcome to Phys.SE. I edited in the Wikipedia link, partly as a convenience to the reader, and partly because Phys.SE usually requires OP to do some minimal research (such as, e.g. checking the pertinent Wikipedia page) before asking. $\endgroup$ – Qmechanic Jun 12 '17 at 14:49

Gravity is described by General Relativity, which is a classical theory. But at very small scales, nature is described by quantum theory, not by the continuity assumed in GR. So far, we have failed to reconcile these two theories. To date, we have no proof of the descreteness of space time. In an ideal world (or universe), GR should describe gravity at any scale, but unfortunately it fails at small scales, giving infinity as the result to many problems.

In addition, you may think more about what we mean by an object at these small scales. If you think of the problem in terms of a grain of sand "jumping" from one side of a spacetime box to another, you are (incorrectly) thinking classically, rather than thinking in quantum mechanical terms.

An associated area that might help you is to read about quantum tunnelling in which the object is treated in wave terms at small scale regimes.

  • $\begingroup$ But dont you think it defies common sense, to state that the Laws of Physics are different for those on large scales and for those on smaller scales, there must be a replica for Quantum Mechanics the one that sounds sensible and not the one that states uncertainity, superposition states etc. $\endgroup$ – Ajinkya Naik Jun 14 '17 at 15:54
  • $\begingroup$ yes, it seems wrong to have this difference, and that's why we are trying to put together a Quantum theory of gravity that would encompass all scales. But common sense may not mean much to nature. It is what it is, ;) $\endgroup$ – user154420 Jun 14 '17 at 16:01
  • $\begingroup$ that is true indeed....oh i see you simplified it just perfectly why we are looking for a Quantum Theory of Gravity...thanks :) $\endgroup$ – Ajinkya Naik Jun 15 '17 at 16:13

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