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UID:UW-Physics-Event-1782
DTSTART:20100226T203000Z
DURATION:PT1H0M0S
DTSTAMP:20260409T005441Z
LAST-MODIFIED:20100211T144329Z
LOCATION:5280 Chamberlin
SUMMARY:Comprehensive Solution to the Cosmological Constant\, Zero-Poi
 nt Energy\, and Quantum Gravity Problems\, NPAC (Nuclear/Particle/Astr
 o/Cosmo) Forum\, Philip Mannheim\, University of Connecticut
DESCRIPTION:We present a solution to the cosmological constant\, the z
 ero-point energy\, and the quantum gravity problems within a single co
 mprehensive framework.We show that in quantum theories of gravity in w
 hich the zero-point energy density of the gravitational field is well-
 defined\, the cosmological<br>
\nconstant and zero-point energy proble
 ms solve each other by mutual<br>
\ncancellation between the cosmologi
 cal constant and the matter and<br>
\ngravitational field zero-point e
 nergy densities. Because of this<br>
\ncancellation\, regulation of th
 e matter field zero-point energy density is not needed\, and thus does
  not cause any trace anomaly to arise. We exhibit our results in two t
 heories of gravity that are well-defined quantum-mechanically. Both of
  these theories are locally conformal invariant\, quantum Einstein gra
 vity in two dimensions and Weyl-tensor-based quantum conformal gravity
  in four dimensions (a fourth-order derivative quantum theory of the t
 ype that Bender and Mannheim have recently shown to be ghost-free and 
 unitary). Central to our approach is the requirement that any and all 
 departures of the geometry from Minkowski are to be brought about by q
 uantum mechanics alone. Consequently\, there have to be no fundamental
  classical fields\, and all mass scales have to be generated by dynami
 cal condensates. In such a situation the trace of the matter field ene
 rgy-momentum tensor is zero\, a constraint that obliges its cosmologic
 al constant and zero-point contributions to cancel each other identica
 lly\, no matter how large they might be. Quantization of the gravitati
 onal field is caused by its coupling to quantized matter fields\, with
  the gravitational field not needing any independent quantization of i
 ts own. With there being no a priori classical curvature\, one does no
 t have to make it compatible with quantization.
URL:https://www.physics.wisc.edu/events/?id=1782
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