Liouville Quantum Gravity with Matter Central Charge in (1, 25): A Probabilistic Approach

Abstract There is a substantial literature concerning Liouville quantum gravity (LQG) in two dimensions with conformal matter field of central charge $${{\mathbf {c}}}_{\mathrm M} \in (-\infty ,1]$$ c M ∈ ( - ∞ , 1 ] . Via the DDK ansatz, LQG can equivalently be describe...

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Main Authors: Gwynne, Ewain, Holden, Nina, Pfeffer, Joshua, Remy, Guillaume
Format: Article
Language:English
Published: Springer Berlin Heidelberg 2021
Online Access:https://hdl.handle.net/1721.1/131446
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author Gwynne, Ewain
Holden, Nina
Pfeffer, Joshua
Remy, Guillaume
author_facet Gwynne, Ewain
Holden, Nina
Pfeffer, Joshua
Remy, Guillaume
author_sort Gwynne, Ewain
collection MIT
description Abstract There is a substantial literature concerning Liouville quantum gravity (LQG) in two dimensions with conformal matter field of central charge $${{\mathbf {c}}}_{\mathrm M} \in (-\infty ,1]$$ c M ∈ ( - ∞ , 1 ] . Via the DDK ansatz, LQG can equivalently be described as the random geometry obtained by exponentiating $$\gamma $$ γ times a variant of the planar Gaussian free field, where $$\gamma \in (0,2]$$ γ ∈ ( 0 , 2 ] satisfies $${\mathbf {c}}_{\mathrm M} = 25 - 6(2/\gamma + \gamma /2)^2$$ c M = 25 - 6 ( 2 / γ + γ / 2 ) 2 . Physics considerations suggest that LQG should also make sense in the regime when $${\mathbf {c}}_{\mathrm M} > 1$$ c M > 1 . However, the behavior in this regime is rather mysterious in part because the corresponding value of $$\gamma $$ γ is complex, so analytic continuations of various formulas give complex answers which are difficult to interpret in a probabilistic setting. We introduce and study a discretization of LQG which makes sense for all values of $${\mathbf {c}}_{\mathrm M} \in (-\infty ,25)$$ c M ∈ ( - ∞ , 25 ) . Our discretization consists of a random planar map, defined as the adjacency graph of a tiling of the plane by dyadic squares which all have approximately the same “LQG size" with respect to the Gaussian free field. We prove that several formulas for dimension-related quantities are still valid for $$\mathbf{c}_{\mathrm M} \in (1,25)$$ c M ∈ ( 1 , 25 ) , with the caveat that the dimension is infinite when the formulas give a complex answer. In particular, we prove an extension of the (geometric) KPZ formula for $$\mathbf{c}_{\mathrm M} \in (1,25)$$ c M ∈ ( 1 , 25 ) , which gives a finite quantum dimension if and only if the Euclidean dimension is at most $$(25-\mathbf{c}_{\mathrm M} )/12$$ ( 25 - c M ) / 12 . We also show that the graph distance between typical points with respect to our discrete model grows polynomially whereas the cardinality of a graph distance ball of radius r grows faster than any power of r (which suggests that the Hausdorff dimension of LQG in the case when $${\mathbf {c}}_{\mathrm M} \in (1,25)$$ c M ∈ ( 1 , 25 ) is infinite). We include a substantial list of open problems.
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spelling mit-1721.1/1314462021-09-21T03:08:41Z Liouville Quantum Gravity with Matter Central Charge in (1, 25): A Probabilistic Approach Gwynne, Ewain Holden, Nina Pfeffer, Joshua Remy, Guillaume Abstract There is a substantial literature concerning Liouville quantum gravity (LQG) in two dimensions with conformal matter field of central charge $${{\mathbf {c}}}_{\mathrm M} \in (-\infty ,1]$$ c M ∈ ( - ∞ , 1 ] . Via the DDK ansatz, LQG can equivalently be described as the random geometry obtained by exponentiating $$\gamma $$ γ times a variant of the planar Gaussian free field, where $$\gamma \in (0,2]$$ γ ∈ ( 0 , 2 ] satisfies $${\mathbf {c}}_{\mathrm M} = 25 - 6(2/\gamma + \gamma /2)^2$$ c M = 25 - 6 ( 2 / γ + γ / 2 ) 2 . Physics considerations suggest that LQG should also make sense in the regime when $${\mathbf {c}}_{\mathrm M} > 1$$ c M > 1 . However, the behavior in this regime is rather mysterious in part because the corresponding value of $$\gamma $$ γ is complex, so analytic continuations of various formulas give complex answers which are difficult to interpret in a probabilistic setting. We introduce and study a discretization of LQG which makes sense for all values of $${\mathbf {c}}_{\mathrm M} \in (-\infty ,25)$$ c M ∈ ( - ∞ , 25 ) . Our discretization consists of a random planar map, defined as the adjacency graph of a tiling of the plane by dyadic squares which all have approximately the same “LQG size" with respect to the Gaussian free field. We prove that several formulas for dimension-related quantities are still valid for $$\mathbf{c}_{\mathrm M} \in (1,25)$$ c M ∈ ( 1 , 25 ) , with the caveat that the dimension is infinite when the formulas give a complex answer. In particular, we prove an extension of the (geometric) KPZ formula for $$\mathbf{c}_{\mathrm M} \in (1,25)$$ c M ∈ ( 1 , 25 ) , which gives a finite quantum dimension if and only if the Euclidean dimension is at most $$(25-\mathbf{c}_{\mathrm M} )/12$$ ( 25 - c M ) / 12 . We also show that the graph distance between typical points with respect to our discrete model grows polynomially whereas the cardinality of a graph distance ball of radius r grows faster than any power of r (which suggests that the Hausdorff dimension of LQG in the case when $${\mathbf {c}}_{\mathrm M} \in (1,25)$$ c M ∈ ( 1 , 25 ) is infinite). We include a substantial list of open problems. 2021-09-20T17:17:07Z 2021-09-20T17:17:07Z 2020-01-16 2020-09-24T20:51:56Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/131446 en https://doi.org/10.1007/s00220-019-03663-6 Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. Springer-Verlag GmbH Germany, part of Springer Nature application/pdf Springer Berlin Heidelberg Springer Berlin Heidelberg
spellingShingle Gwynne, Ewain
Holden, Nina
Pfeffer, Joshua
Remy, Guillaume
Liouville Quantum Gravity with Matter Central Charge in (1, 25): A Probabilistic Approach
title Liouville Quantum Gravity with Matter Central Charge in (1, 25): A Probabilistic Approach
title_full Liouville Quantum Gravity with Matter Central Charge in (1, 25): A Probabilistic Approach
title_fullStr Liouville Quantum Gravity with Matter Central Charge in (1, 25): A Probabilistic Approach
title_full_unstemmed Liouville Quantum Gravity with Matter Central Charge in (1, 25): A Probabilistic Approach
title_short Liouville Quantum Gravity with Matter Central Charge in (1, 25): A Probabilistic Approach
title_sort liouville quantum gravity with matter central charge in 1 25 a probabilistic approach
url https://hdl.handle.net/1721.1/131446
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