PSU: Beyond the Black Hole Singularity

[bystander]

Beyond the Black Hole Singularity
Penn State University | Eberly College of Science | 2018 Dec 20

Artist depiction of loop quantum gravity effects in a black hole. The bottom half of the image depicts the black hole which, according to general relativity, traps everything including light. Loop quantum gravity, a theory that extends Einstein's general relativity using quantum mechanics, overcomes this tremendous pull and liberates everything shown in the top half of image, thus solving the fundamental problem of black hole singularity. (Credit: A. Corichi and J. P. Ruiz)

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Our first glimpses into the physics that exist near the center of a black hole are being made possible using “loop quantum gravity”—a theory that uses quantum mechanics to extend gravitational physics beyond Einstein’s theory of general relativity. Loop quantum gravity, originated at Penn State and subsequently developed by a large number of scientists worldwide, is opening up a new paradigm in modern physics. The theory has emerged as a leading candidate to analyze extreme cosmological and astrophysical phenomena in parts of the universe, like black holes, where the equations of general relativity cease to be useful.

Previous work in loop quantum gravity that was highly influential in the field analyzed the quantum nature of the Big Bang, and now two new papers ... extend those results to black hole interiors. ...

At the center of a black hole the gravity is so strong that, according to general relativity, space-time becomes so extremely curved that ultimately the curvature becomes infinite. This results in space-time having a jagged edge, beyond which physics no longer exists—the singularity. Another example of a singularity is the Big Bang. Asking what happened before the Big Bang is a meaningless question in general relativity, because space-time ends, and there is no before. But modifications to Einstein’s equations that incorporated quantum mechanics through loop quantum gravity allowed researchers to extend physics beyond the Big Bang and make new predictions. The two recent papers have accomplished the same thing for the black hole singularity. ...

Beyond Einstein
Louisiana State University | 2018 Dec 20

Quantum Extension of the Kruskal Space-time ~ Abhay Ashtekar, Javier Olmedo, Parampreet Singh

• Physical Review D 98(12):6003 (15 Dec 2018) DOI: 10.1103/PhysRevD.98.126003
  arXiv.org > gr-qc > arXiv:1806.02406 > 06 Jun 2018 (v1), 09 Nov 2018 (v2)

Quantum Transfiguration of Kruskal Black Holes ~ Abhay Ashtekar, Javier Olmedo, Parampreet Singh

• Physical Review Letters 121(24):1301 (14 Dec 2018) DOI: 10.1103/PhysRevLett.121.241301
  arXiv.org > gr-qc > arXiv:1806.00648 > 02 Jun 2018 (v1), 09 Nov 2018 (v2)