Publications
My articles, roughly sorted by topic (click on the topic title to see a short description, when available).
For different arrangements and metadata, check inSPIRE or Google Scholar .
For different arrangements and metadata, check inSPIRE or Google Scholar .
On long-range models:
Long-range models are Euclidean field theories whose action has a nonlocal kinetic term, where the ordinary Laplacian is replaced by a fractional power of the Laplacian. They are interesting from a theoretical (and mathematical physics) point of view, as well as from a condensed matter point of view, as their lattice versions describe systems that can be realized experimentally via trapped ions or quantum gases in cavities (see arXiv:2109.01063 for a review). See the introductions of the papers below for a slightly more detailed but still brief motivation and list of references. Notice that also most of the papers on "QFTs in the melonic large-N limit" (below) deal with long-range models; here I list only work on non-melonic models.
with R. Gurau, D. Lettera: "Dynamic critical exponent in quantum long-range models", [arXiv:2404.13963 [hep-th]]. NEW
with R. Gurau, S. Harribey, D. Lettera: "Finite-size versus finite-temperature effects in the critical long-range O(N) model", JHEP 02 (2024) 078 [arXiv:2311.04607 [hep-th]].
with R. Gurau, S. Harribey, K. Suzuki: "Long-range multi-scalar models at three loops", J. Phys. A: Math. Theor. 53 (2020) 445008 [arXiv:2007.04603 [hep-th]].
Other recent directions:
with R. Gurau, H. Keppler, D. Lettera: "The small-N series in the zero-dimensional O(N) model: constructive expansions and transseries", Ann. Henri Poincaré (2024). https://doi.org/10.1007/s00023-024-01437-y [arXiv:2210.14776 [hep-th]].
"Instability of complex CFTs with operators in the principal series", JHEP 05 (2021) 004 [arXiv:2103.01813 [hep-th]].
On quantum field theories in the melonic large-N limit:
These are quantum (or statistical) field theories whose large-N perturbative expansion is dominated by melonic diagrams. This sets them apart from vector or matrix models (dominated by cactus and planar diagrams, respectively), and makes their renormalization and fixed points controllable. Therefore, they serve as interesting toy models to explore interacting fixed points of the renormalization group and to apply conformal field theory techniques. The main example of such theories are tensor models (a typical example being theories with a global O(N)^3 invariance), but there are also other models, such as SYK and Amit-Roginsky. It should be said that these tensor models are ordinary field theories on a fixed spacetime and have no direct relation to quantum gravity (except perhaps via holography, as for SYK), unlike the purely combinatorial tensor models (see below).
The thesis for my French Habilitation (HDR) is mainly based on this line of research.
with R. Gurau, S. Harribey, D. Lettera: "The F-theorem in the melonic limit", JHEP 02 (2022) 147 [arXiv:2111.11792 [hep-th]].
with N. Delporte: "Remarks on a melonic field theory with cubic interactions", JHEP 04 (2021) 197 [arXiv:2012.12238 [hep-th]].
with R. Gurau, S. Harribey: "The tri-fundamental quartic model", Phys. Rev. D 103 (2021) 046018 [arXiv:2011.11276 [hep-th]].
"Melonic CFTs", Contribution to the proceedings of CORFU2019 [arXiv:2004:08616 [hep-th]].
with R. Gurau, K. Suzuki:"Conformal Symmetry and Composite Operators in the O(N)^3 Tensor Field Theory", JHEP 06 (2020) 113 [arXiv:2002.07652 [hep-th]].
with I. Costa: "SO(3)-invariant phase of the O(N)^3 tensor model", Phys. Rev. D 101 (2020) 086021 [arXiv:1912.07311 [hep-th]].
with N. Delporte, S. Harribey, R. Sinha: "Sextic tensor field theories in rank 3 and 5", JHEP 06 (2020) 065 [arXiv:1912.06641 [hep-th]].
with R. Gurau, S. Harribey, K. Suzuki: "Hints of unitarity at large N in the O(N)^3 tensor field theory", JHEP 02 (2020) 072 [arXiv:1909.07767 [hep-th]].
with R. Gurau, S. Harribey: "Line of fixed points in a bosonic tensor model", JHEP 06 (2019) 053 [arXiv:1903.03578 [hep-th]].
with N. Delporte: "Phase diagram and fixed points of tensorial Gross-Neveu models in three dimensions", JHEP 01 (2019) 218 [arXiv:1810.04583 [hep-th]].
with R. Gurau: "2PI effective action for the SYK model and tensor field theories", JHEP 05 (2018) 156 [arXiv:1802.05500 [hep-th]].
with S. Carrozza, R. Gurau, A. Sfondrini: "Tensorial Gross-Neveu models", JHEP 01 (2018) 003 [arXiv:1710.10253 [hep-th]].
On tensor models as models of random geometry (purely combinatorial field theories in zero dimensions):
These are purely combinatorial models (the random variables have no spacetime dependence, or in other words they are fields on zero dimensional spacetime), whose Feynman diagrams can be interpreted as simplicial (pseudo-)manifolds, i.e. they generalize to higher dimensional manifolds the relations between matrix models and random triangulations. From this point of view, the large-N melonic dominance corresponds to a branched polymer phase of quantum gravity (as found numerically in dynamical triangulations). Putting aside such interpretation and its geometric constructions, the classification of diagrams in the 1/N expansion that one finds in these models applies also to tensor models on a higher-dimensional spacetime, as the power of N associated to a diagram only depends on the combinatorial tensor structure.
with S. Carrozza, R. Toriumi, G. Valette: "Multiple scaling limits of U(N)^2×O(D) multi-matrix models", Ann. Inst. Henri Poincaré Comb. Phys. Interact. 9 (2022), no. 2, pp. 367-433 [arXiv:2003.02100 [math-ph]].
with S. Carrozza, R. Gurau, M. Kolanowski: "The 1/N expansion of the symmetric traceless and the antisymmetric tensor models in rank three", Commun. Math. Phys. 371 (2019) 55 [arXiv:1712.00249 [hep-th]].
with R. Gurau: "Symmetry breaking in tensor models", Phys. Rev. D 92 (2015) 104041 [arXiv:1506.08542 [hep-th]].
with R. Gurau: "Phase transition in dually weighted colored tensor models", Nucl. Phys. B 855 (2012) 420-437 [arXiv:1108.5389 [hep-th]].
On tensorial group field theory (Kontsevich-type tensor models):
These models can be viewed in at least two different ways. In the first interpretation, they are zero-dimensional random tensor models as above, but with a Gaussian part of the Boltzmann weight having a nontrivial index-dependent covariance, breaking the global symmetry of the interactions. From such a point of view, they can be thought as a tensor generalization of the Kontsevich matrix model. In a second interpretation, one can think of the tensor as a scalar field in momentum space, the tensor indices being the components of momentum (taking discrete values because of compactness of space), and N being a UV cutoff; from this point of view the Gaussian part is rather standard (though sometimes long-range), while the interactions have a peculiar type of non-locality. From this second point of view, it is natural to consider a renormalization group flow of the model with respect to N. Either way, these models find their main motivation as simplified versions of a larger class of quantum gravity models.
with V. Lahoche: "Functional Renormalization Group Approach for Tensorial Group Field Theory: A Rank-6 Model with Closure Constraint", Class. Quant. Grav. 33 (2016) 095003 [arXiv:1508.06384 [hep-th]].
with J. Ben Geloun, D. Oriti: "Functional Renormalisation Group Approach for Tensorial Group Field Theory: a Rank-3 Model", JHEP 03 (2015) 084 [arXiv:1411.3180 [hep-th]].
On asymptotically safe gravity:
That is, on the conjecture (originally proposed by Steven Weinberg in 1976) that the quantum field theory of gravity is nonperturbatively renormalizable, in the sense that it is defined as a relevant perturbation of a nontrivial (i.e. interacting) UV fixed point. See the Wikipedia entry for a start.
"Essential nature of Newton's constant in unimodular gravity", Gen.Rel.Grav. 48 (2016) 68 [arXiv:1511.06560 [hep-th]].
with F. Guarnieri: "Brans-Dicke theory in the local potential approximation", New J.Phys. 16 (2014) 053051 [arXiv:1311.1081 [hep-th]].
"On the number of relevant operators in asymptotically safe gravity", EPL 102 (2013) 20007 [arXiv:1301.4422 [hep-th]].
with F. Caravelli: "The local potential approximation in quantum gravity", JHEP 06 (2012) 017 [arXiv:1204.3541 [hep-th]].
"Asymptotic safety goes on shell", New J. Phys. 14 (2012) 015005 [arXiv: 1107.3110 [hep-th]].
with K. Groh, P.F. Machado, F. Saueressig: "The Universal RG Machine", JHEP 06 (2011) 079 [arXiv:1012.3081 [hep-th]].
with P.F. Machado, F. Saueressig: "Four-derivative interactions in asymptotically safe gravity", Proceedings of the XXV Max Born Symposium "The Planck Scale", Wroclaw, 29 June - 3 July, 2009 [arXiv:0909.3265 [hep-th]].
with P.F. Machado, F. Saueressig: "Taming perturbative divergences in asymptotically safe gravity", Nucl. Phys. B 824 (2010) 168-191, [arXiv:0902.4630 [hep-th]].
with P.F. Machado, F. Saueressig: "Asymptotic safety in higher-derivative gravity", Mod. Phys. Lett. A 24 (2009) 2233-2241 [arXiv:0901.2984 [hep-th]].
On renormalization group in various models of gravity, or in field theories on curved background:
These are just some unrelated papers, having in common only the renormalization group perspective :)
"Critical behavior in spherical and hyperbolic spaces", J. Stat. Mech. (2015) P01002 [arXiv:1403.6712 [cond-mat]].
with F. Guarnieri: "One-loop renormalization in a toy model of Horava-Lifshitz gravity", JHEP 03 (2014) 078 [arXiv:1311.6253 [hep-th]].
with S. Speziale: "Perturbative running of the Immirzi parameter", Proceedings of Loops'11, Madrid, J. Phys.: Conf. Ser. 360, 012011 [arXiv:1111.0884 [hep-th]].
with S. Speziale: "Perturbative quantum gravity with the Immirzi parameter", JHEP 06 (2011) 107 [arXiv:1104.4028 [hep-th]].
On Causal Dynamical Triangulations:
An approach to quantum gravity, defining a regularized path integral in terms of simplicial manifolds, along the old idea of Tullio Regge. In CDT, the edge lengths are fixed, but one sums over all possible gluings of the building blocks, respecting a certain foliation structure. See for example arXiv:1203.3591 for a review.
"Landau theory of Causal Dynamical Triangulations", Invited chapter for the Section "Causal Dynamical Triangulations" of the "Handbook of Quantum Gravity" (Eds. C. Bambi, L. Modesto and I.L. Shapiro, Springer Singapore, expected in 2023) [arXiv:2212.11043 [hep-th]]. NEW
with J. P. Ryan: "Capturing the phase diagram of (2+1)-dimensional CDT using a balls-in-boxes model", Class. Quant. Grav. 34 (2017) 105012 [arXiv:1612.09533 [hep-th]].
with J. Henson: "Spacetime condensation in (2+1)-dimensional CDT from a Horava-Lifshitz minisuperspace model", Class. Quant. Grav. 32 (2015) 215007 [arXiv:1410.0845 [gr-qc]].
(see also the related blog entry for CQG+)with J. Henson: "Spectral geometry as a probe of quantum spacetime", Phys. Rev. D 80 (2009) 124036 [arXiv:0911.0401 [hep-th]].
with J. Henson: "Imposing causality on a matrix model", Phys. Lett. B 678 (2009) 222-226 [arXiv:0812.4261 [hep-th]].
"Quantum gravity from simplices: analytical investigations of Causal Dynamical Triangulations", PhD Thesis, Utrecht University Repository [arXiv:0707.3070 [gr-qc]].
with R. Loll, F. Zamponi: "(2+1)-Dimensional quantum gravity as the continuum limit of causal dynamical triangulations", Phys. Rev. D 76 (2007) 104022 [arXiv:0704.3214 [hep-th]].
with R. Loll: "Quantum gravity and matter: counting graphs on Causal Dynamical Triangulations", Gen. Rel. Grav. 39 (2007) 863-898 [arXiv:gr-qc/0611075].
with R. Loll: "Unexpected spin-off from quantum gravity", Physica A 377 (2007) 373-380 [arXiv:hep-lat/0603013].
On quantum group symmetries/non-commutative geometry/DSR:
This goes back to my undergraduate studies, with a brief revival during the beginning of my first postdoc. The main idea at the root of these studies is that quantum gravity effects might manifest themselves at intermediate energies as a deformation of the classical spacetime symmetries, such as k-Poincaré, which is a quantum group deformation of the Poincaré group.
"Fractal properties of quantum spacetime", Phys. Rev. Lett. 102 (2009) 111303 [arXiv:0811.1396 [hep-th]
(PhysOrg featured a story on this).with M. Arzano: "Rainbow statistics", Int. J. Mod. Phys. A 24 (2009) 4623-4641 [arXiv:0809.0889 [hep-th]].
with G. Amelino-Camelia, F. D'Andrea, A. Procaccini: "Comparison of relativity theories with observer-independent scales of both velocity and length/mass", Class. Quant. Grav. 20 (2003) 5353-5370 [arXiv:hep-th/0201245].