\nconstant and zero-point energy proble ms solve each other by mutual

\ncancellation between the cosmologi cal constant and the matter and

\ngravitational field zero-point e nergy densities. Because of this

\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 END:VEVENT END:VCALENDAR