beecee Posted October 27, 2017 Share Posted October 27, 2017 (edited) Physicists propose test of quantum gravity using current technology October 27, 2017 by Lisa Zyga Proposed experimental setup to probe the effects of noncommutative structure. Credit: S. Dey et al. ©2017 Nuclear Physics B Physicists have proposed a way to test quantum gravity that, in principle, could be performed by a laser-based, table-top experiment using currently available technology. Although a theory of quantum gravity would overcome one of the biggest challenges in modern physics by unifying general relativity and quantum mechanics, currently physicists have no way of testing any proposed theories of quantum gravity. Read more at: https://phys.org/news/2017-10-physicists-quantum-gravity-current-technology.html#jCp the paper: http://www.sciencedirect.com/science/article/pii/S055032131730319X Probing noncommutative theories with quantum optical experiments Abstract One of the major difficulties of modern science underlies at the unification of general relativity and quantum mechanics. Different approaches towards such theory have been proposed. Noncommutative theories serve as the root of almost all such approaches. However, the identification of the appropriate passage to quantum gravity is suffering from the inadequacy of experimental techniques. It is beyond our ability to test the effects of quantum gravity thorough the available scattering experiments, as it is unattainable to probe such high energy scale at which the effects of quantum gravity appear. Here we propose an elegant alternative scheme to test such theories by detecting the deformations emerging from the noncommutative structures. Our protocol relies on the novelty of an opto-mechanical experimental setup where the information of the noncommutative oscillator is exchanged via the interaction with an optical pulse inside an optical cavity. We also demonstrate that our proposal is within the reach of current technology and, thus, it could uncover a feasible route towards the realization of quantum gravitational phenomena thorough a simple table-top experiment. Edited October 27, 2017 by beecee Link to comment Share on other sites More sharing options...
jimmydasaint Posted October 27, 2017 Share Posted October 27, 2017 I don't understand the Abstract mate. Can you present the theory in your own words to the best of your understanding Thank you. Link to comment Share on other sites More sharing options...
Strange Posted October 27, 2017 Share Posted October 27, 2017 There is a slightly clearer example here: https://phys.org/news/2017-10-physicists-quantum-gravity-current-technology.html But not much ... Link to comment Share on other sites More sharing options...
jimmydasaint Posted October 28, 2017 Share Posted October 28, 2017 Thanks for that info Strange. I am now going to try and summarise, from a layman's point of view, the Classical Model of physics using an explanatory diagram: Credit : https://creativecommons.org/licenses/by-sa/3.0/ Wiki From my limited viewpoint, the Classical Model uses the theories of Newton, Maxwell and Einstein but does not provide a link between behaviour at large scales (e.g. stars, planets, humans) and at an atomic/subatomic (quantum) scale. Quantum mechanic theories (e.g. string theory) do not lend themselves to experimentation normally but this experiment may be able to explain something about gravity at quantum scales without using energy at higher scales than the Large Hadron Collider. Right so far? If so, let's consider the simplified version of the paper supplied by Strange... Link to comment Share on other sites More sharing options...
jimmydasaint Posted October 28, 2017 Share Posted October 28, 2017 (edited) beecee, I think that this comment gets to the heart of what the scientists are trying to do at what can be considered "low" energies in comparison to the energies used in the LHC (50-7-MeV IIRC): Quote One of the consequences of a noncommutative spacetime is that there are no singularities, which has implications for other areas of cosmology, such as the big bang and black holes. With their proposed test, the physicists' goal is to find experimental evidence supporting the idea that spacetime does indeed have a noncommutative structure. To do this, the proposed test attempts to detect any changes in the conventional commutative relations occurring in a micromechanical oscillator. If these changes are present, they would indicate a noncommutative structure and produce a measurable optical phase shift on a light pulse that has been coupled to the oscillator. Using current optical setups, this phase shift can be measured with sufficiently high levels of accuracy that, according to the physicists' calculations, would make it possible to access the energy scale near the Planck length. By accessing this scale, the experiment could potentially probe the effects of noncommutative theories at the energy regime relevant to quantum gravity. Read more at: https://phys.org/news/2017-10-physicists-quantum-gravity-current-technology.html#jCp For people who need a simple explanation of non commutativity, I highly recommend the following: https://physics.stackexchange.com/questions/10362/how-does-non-commutativity-lead-to-uncertainty The following is a phase shift from an oscillator: from THz oscillator. Physics bods, help us out with an explanation of the proposed new experiments.... Edited October 28, 2017 by jimmydasaint Link to comment Share on other sites More sharing options...
beecee Posted October 31, 2017 Author Share Posted October 31, 2017 On 10/29/2017 at 9:14 AM, jimmydasaint said: beecee, I think that this comment gets to the heart of what the scientists are trying to do at what can be considered "low" energies in comparison to the energies used in the LHC (50-7-MeV IIRC): For people who need a simple explanation of non commutativity, I highly recommend the following: https://physics.stackexchange.com/questions/10362/how-does-non-commutativity-lead-to-uncertainty The following is a phase shift from an oscillator: from THz oscillator. Physics bods, help us out with an explanation of the proposed new experiments.... Thanks for the extra info jimmy....The link Strange gave giving the more lay person's explanation, was given in the OP just before the link to the paper. Link to comment Share on other sites More sharing options...
Strange Posted October 31, 2017 Share Posted October 31, 2017 2 hours ago, beecee said: The link Strange gave giving the more lay person's explanation, was given in the OP just before the link to the paper. How odd ... I completely missed that. Link to comment Share on other sites More sharing options...
beecee Posted November 1, 2017 Author Share Posted November 1, 2017 On 10/31/2017 at 6:49 PM, Strange said: How odd ... I completely missed that. Don't take it so hard! These things happen. Link to comment Share on other sites More sharing options...
Strange Posted November 4, 2017 Share Posted November 4, 2017 Some people are less than impressed with this paper: http://backreaction.blogspot.co.uk/2017/10/no-you-still-cannot-probe-quantum.html Link to comment Share on other sites More sharing options...
beecee Posted November 4, 2017 Author Share Posted November 4, 2017 32 minutes ago, Strange said: Some people are less than impressed with this paper: http://backreaction.blogspot.co.uk/2017/10/no-you-still-cannot-probe-quantum.html Interesting indeed! Thanks Strange. I suppose I need to be more aware of physorg and the occasional error ridden science article. Link to comment Share on other sites More sharing options...
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