4.9 Coupling to matter fields4 Dynamical triangulations4.7 Influence of the measure

4.8 Higher-derivative terms

Higher-order derivative terms were considered by Ambjørn et al [16Jump To The Next Citation Point In The Article] (see also [143]), who added a term of the form

  equation800

to the action, where again tex2html_wrap_inline3029 and o (b) denotes the number of 4-simplices sharing a bone b . For tex2html_wrap_inline3035, and with volumes up to 32 k, no major qualitative changes of the geometrical observables were found. The inclusion of the higher-derivative term also does not improve the behaviour of the average curvature tex2html_wrap_inline2489, which continues to be positive at the critical point, whereas from a naïve comparison with the continuum theory one would expect it to scale to zero. (This is also incompatible with the prediction of Antoniadis et al [20], should dynamical triangulations possess an infrared stable fixed point.) De Bakker and Smit [89] have argued that this may not be a reason of concern, since one expects the volume and curvature terms to mix under renormalization.



4.9 Coupling to matter fields4 Dynamical triangulations4.7 Influence of the measure

image Discrete Approaches to Quantum Gravity in Four Dimensions
Renate Loll
http://www.livingreviews.org/lrr-1998-13
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