The poll is set up to accept multiple choices. Check off the paper or papers you predict will have the most significant impact on future QG research. If you have one that is not on the list, post the arxiv link, title and author(s) on this thread, to be counted as a "write-in". 1. Loop quantum cosmology of Bianchi I models (Ashtekar et al) 2. Asymptotic analysis of the EPRL four-simplex amplitude (Barrett et al) 3. Taming perturbative divergences in asymptotically safe gravity (Benedetti et al) 4. Particle Topology, Braids, and Braided Belts (Bilson-Thompson et al) 5. From lattice BF gauge theory to area-angle Regge calculus (Bonzom) 6. Quantum geometry from phase space reduction (Freidel et al) 7. Quantum Gravity at a Lifgarbagez Point (Horava) 8. 4d Deformed Special Relativity from Group Field Theories (Livine et al) 9. Group field theory and simplicial quantum gravity (Oriti) 10.Disordered Locality as an Explanation for the Dark Energy (Smolin et al) Our most recent previous MIP poll is here: https://www.physicsforums.com/showthread.php?t=282166 Links and additional information on the papers: Ashtekar et al http://arxiv.org/abs/0903.3397 Loop quantum cosmology of Bianchi I models Abhay Ashtekar, Edward Wilson-Ewing (Submitted on 19 Mar 2009) "The 'improved dynamics' of loop quantum cosmology is extended to include anisotropies of the Bianchi I model. As in the isotropic case, a massless scalar field serves as a relational time parameter. However, the extension is non-trivial because one has to face several conceptual subtleties as well as technical difficulties. These include: a better understanding of the relation between loop quantum gravity (LQG) and loop quantum cosmology (LQC); handling novel features associated with the non-local field strength operator in presence of anisotropies; and finding dynamical variables that make the action of the Hamiltonian constraint manageable. Our analysis provides a conceptually complete description that overcomes limitations of earlier works. We again find that the big bang singularity is resolved by quantum geometry effects but, because of the presence of Weyl curvature, Planck scale physics is now much richer than in the isotropic case. Since the Bianchi I models play a key role in the Belinskii, Khalatnikov, Lifgarbagez (BKL) conjecture on the nature of generic space-like singularities in general relativity, the quantum dynamics of Bianchi I cosmologies is likely to provide considerable intuition about the fate of generic space-like singularities in quantum gravity. Finally, we show that the quantum dynamics of Bianchi I cosmologies projects down exactly to that of the Friedmann model. This opens a new avenue to relate more complicated models to simpler ones, thereby providing a new tool to relate the quantum dynamics of LQG to that of LQC." Barrett et al http://arxiv.org/abs/0902.1170 Asymptotic analysis of the EPRL four-simplex amplitude John W. Barrett, Richard J. Dowdall, Winston J. Fairbairn, Henrique Gomes, Frank Hellmann "An asymptotic formula for a certain 4d Euclidean spin foam 4-simplex amplitude is given for the limit of large spins. The analysis covers the model with Immirzi parameter less than one defined separately by Engle, Livine, Pereira and Rovelli (EPRL) and Freidel and Krasnov (FK). We are also able to analyse the EPRL model with Immirzi parameter greater than one. The asymptotic formula has one term which is proportional to the cosine of the Regge action for gravity, and it is shown that this term is present whenever the boundary data determines a non-degenerate Euclidean geometry for the 4-simplex. A scheme for resolving the phase ambiguity of the boundary data in these cases is also presented." Benedetti et al http://arxiv.org/abs/0902.4630 Taming perturbative divergences in asymptotically safe gravity Dario Benedetti, Pedro F. Machado, Frank Saueressig 16 pages (Submitted on 26 Feb 2009) "We use functional renormalization group methods to study gravity minimally coupled to a free scalar field. This setup provides the prototype of a gravitational theory which is perturbatively non-renormalizable at one-loop level, but may possess a non-trivial renormalization group fixed point controlling its UV behavior. We show that such a fixed point indeed exists within the truncations considered, lending strong support to the conjectured asymptotic safety of the theory. In particular, we demonstrate that the counterterms responsible for its perturbative non-renormalizability have no qualitative effect on this feature." Bilson-Thompson et al http://arxiv.org/abs/0903.1376 Particle Topology, Braids, and Braided Belts Sundance Bilson-Thompson, Jonathan Hackett, Louis H. Kauffman 21 pages, 16 figures (Submitted on 7 Mar 2009) "Recent work suggests that topological features of certain quantum gravity theories can be interpreted as particles, matching the known fermions and bosons of the first generation in the Standard Model. This is achieved by identifying topological structures with elements of the framed Artin braid group on three strands, and demonstrating a correspondence between the invariants used to characterise these braids (a braid is a set of non-intersecting curves, that connect one set of N points with another set of N points), and quantities like electric charge, colour charge, and so on. In this paper we show how to manipulate a modified form of framed braids to yield an invariant standard form for sets of isomorphic braids, characterised by a vector of real numbers. This will serve as a basis for more complete discussions of quantum numbers in future work." Bonzom http://arxiv.org/abs/0903.0267 From lattice BF gauge theory to area-angle Regge calculus Valentin Bonzom 18 pages, 2 figures "We consider Riemannian 4d BF lattice gauge theory, on a triangulation of spacetime. Introducing the simplicity constraints which turn BF theory into simplicial gravity, some geometric quantities of Regge calculus, areas, and 3d and 4d dihedral angles, are identified. The parallel transport conditions are taken care of to ensure a consistent gluing of simplices. We show that these gluing relations, together with the simplicity constraints, contain the constraints of area-angle Regge calculus in a simple way, via the group structure of the underlying BF gauge theory. This provides a precise road from constrained BF theory to area-angle Regge calculus. Doing so, a framework combining variables of lattice BF theory and Regge calculus is built. The action takes a form à la Regge and includes the contribution of the Immirzi parameter. In the absence of simplicity constraints, the standard spin foam model for BF theory is recovered. Insertions of local observables are investigated, leading to Casimir insertions for areas and 6j-symbols for 3d angles. The present formulation is argued to be suitable for deriving spin foam models from discrete path integrals." Freidel et al http://arxiv.org/abs/0902.0351 Quantum geometry from phase space reduction Florian Conrady, Laurent Freidel 31 pages, 1 figure "In this work we give an explicit isomorphism between the usual spin network basis and the direct quantization of the reduced phase space of tetrahedra. The main outcome is a formula that describes the space of SU(2) invariant states by an integral over coherent states satisfying the closure constraint exactly, or equivalently, as an integral over the space of classical tetrahedra. This provides an explicit realization of theorems by Guillemin--Sternberg and Hall that describe the commutation of quantization and reduction. In the final part of the paper, we use our result to express the FK spin foam model as an integral over classical tetrahedra and the asymptotics of the vertex amplitude is determined." Horava http://arxiv.org/abs/0901.3775 Quantum Gravity at a Lifgarbagez Point Petr Horava 29 pages "We present a candidate quantum field theory of gravity with dynamical critical exponent equal to z=3 in the UV. (As in condensed matter systems, z measures the degree of anisotropy between space and time.) This theory, which at short distances describes interacting nonrelativistic gravitons, is power-counting renormalizable in 3+1 dimensions. When restricted to satisfy the condition of detailed balance, this theory is intimately related to topologically massive gravity in three dimensions, and the geometry of the Cotton tensor. At long distances, this theory flows naturally to the relativistic value z=1, and could therefore serve as a possible candidate for a UV completion of Einstein's general relativity or an infrared modification thereof. The effective speed of light, the Newton constant and the cosmological constant all emerge from relevant deformations of the deeply nonrelativistic z=3 theory at short distances." Livine et al http://arxiv.org/abs/0903.3475 4d Deformed Special Relativity from Group Field Theories Florian Girelli, Etera R. Livine, Daniele Oriti 23 pages (Submitted on 20 Mar 2009) "We derive a scalar field theory of the deformed special relativity type, living on non-commutative kappa-Minkowski spacetime and with a kappa-deformed Poincare symmetry, from the SO(4,1) group field theory defining the transition amplitudes for topological BF-theory in 4 space-time dimensions. This is done at a non-perturbative level of the spin foam formalism working directly with the group field theory (GFT). We show that matter fields emerge from the fundamental model as perturbations around a specific phase of the GFT, corresponding to a solution of the fundamental equations of motion, and that the non-commutative field theory governs their effective dynamics." Oriti http://arxiv.org/abs/0902.3903 Group field theory and simplicial quantum gravity Daniele Oriti (Submitted on 23 Feb 2009) "We present a new Group Field Theory for 4d quantum gravity. It incorporates the constraints that give gravity from BF theory, and has quantum amplitudes with the explicit form of simplicial path integrals for 1st order gravity. The geometric interpretation of the variables and of the contributions to the quantum amplitudes is manifest. This allows a direct link with other simplicial gravity approaches, like quantum Regge calculus, in the form of the amplitudes of the model, and dynamical triangulations, which we show to correspond to a simple restriction of the same." Smolin et al http://arxiv.org/abs/0903.5303 Disordered Locality as an Explanation for the Dark Energy Chanda Prescod-Weinstein, Lee Smolin 12 pages (Submitted on 30 Mar 2009) "We discuss a novel explanation of the dark energy as a manifestation of macroscopic non-locality coming from quantum gravity, as proposed by Markopoulou. It has been previously suggested that in a transition from an early quantum geometric phase of the universe to a low temperature phase characterized by an emergent spacetime metric, locality might have been 'disordered'. This means that there is a mismatch of micro-locality, as determined by the microscopic quantum dynamics and macro-locality as determined by the classical metric that governs the emergent low energy physics. In this paper we discuss the consequences for cosmology by studying a simple extension of the standard cosmological models with disordered locality. We show that the consequences can include a naturally small vacuum energy."