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Publikasjoner (6 av 6) Visa alla publikasjoner
Courteaut, K. & Johansson, K. (2025). Partition function for the 2d Coulomb gas on a Jordan curve. Annales Fennici Mathematici, 50(1), 109-144
Åpne denne publikasjonen i ny fane eller vindu >>Partition function for the 2d Coulomb gas on a Jordan curve
2025 (engelsk)Inngår i: Annales Fennici Mathematici, ISSN 2737-0690, E-ISSN 2737-114X, Vol. 50, nr 1, s. 109-144Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We prove an asymptotic formula for the partition function of a 2d Coulomb gas at inverse temperature beta > 0, confined to lie on a Jordan curve. The partition function can include a linear statistic. The asymptotic formula involves a Fredholm determinant related to the Loewner energy of the curve, and also an expression involving the sampling function, the exterior conformal map for the curve and the Grunsky operator. The asymptotic formula also gives a central limit theorem for linear statistics of the particles in the gas.

sted, utgiver, år, opplag, sider
Finnish Mathematical Society, 2025
Emneord
Log-gas, Coulomb gas, Jordan curve, partition function, free energy, Central Limit Theorem, global fluctuations, linear statistic
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-361871 (URN)10.54330/afm.159822 (DOI)001445841500003 ()2-s2.0-105001531220 (Scopus ID)
Merknad

QC 20250401

Tilgjengelig fra: 2025-04-01 Laget: 2025-04-01 Sist oppdatert: 2026-03-30bibliografisk kontrollert
Courteaut, K., Johansson, K. & Lambert, G. (2024). From Berry–Esseen to super-exponential. Electronic Journal of Probability, 29, Article ID 11.
Åpne denne publikasjonen i ny fane eller vindu >>From Berry–Esseen to super-exponential
2024 (engelsk)Inngår i: Electronic Journal of Probability, E-ISSN 1083-6489, Vol. 29, artikkel-id 11Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

For any integer m < n, where m can depend on n, we study the rate of convergence (Formula Presented) to its limiting Gaussian as n → ∞ for orthogonal, unitary and symplectic Haar distributed random matrices U of size n. In the unitary case, we prove that the total variation distance is less than (Formula Presented) times a constant. This result interpolates between the super-exponential bound obtained for fixed m and the 1/n bound coming from the Berry–Esseen theorem applicable when m ≥ n by a result of Rains. We obtain analogous results for the orthogonal and symplectic groups. In these cases, our total variation upper bound takes the form (Formula Presented) times a constant and the result holds provided n > 2m. For m = 1, we obtain complementary lower bounds and precise asymptotics for the L2-distances as n → ∞, which show how sharp our results are.

sted, utgiver, år, opplag, sider
Institute of Mathematical Statistics, 2024
Emneord
classical compact groups, Haar measure, Hankel determinants, rate of convergence, Toeplitz determinants
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-344004 (URN)10.1214/23-EJP1068 (DOI)001165378300001 ()2-s2.0-85185324572 (Scopus ID)
Merknad

QC 20240229

Tilgjengelig fra: 2024-02-28 Laget: 2024-02-28 Sist oppdatert: 2025-12-05bibliografisk kontrollert
Courteaut, K. & Johansson, K. (2024). Multivariate normal approximation for traces of orthogonal and symplectic matrices. Annales de l'I.H.P. Probabilites et statistiques, 60(1), 312-342
Åpne denne publikasjonen i ny fane eller vindu >>Multivariate normal approximation for traces of orthogonal and symplectic matrices
2024 (engelsk)Inngår i: Annales de l'I.H.P. Probabilites et statistiques, ISSN 0246-0203, E-ISSN 1778-7017, Vol. 60, nr 1, s. 312-342Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We show that the distance in total variation between (Tr U, √12 Tr U2, . . ., √m Tr Um) and a real Gaussian vector, where 1 U is a Haar distributed orthogonal or symplectic matrix of size 2n or 2n + 1, is bounded by 「 (2 mn + 1)− 12 times a correction. The correction term is explicit and holds for all n ≥ m4, for m sufficiently large. For n ≥ m3 we obtain the bound (mn)−c √ mn with an explicit constant c. Our method of proof is based on an identity of Toeplitz + Hankel determinants due to Basor and Ehrhardt, see (Oper. Matrices 3 (2009) 167–86), which is also used to compute the joint moments of the traces.

sted, utgiver, år, opplag, sider
Institute of Mathematical Statistics, 2024
Emneord
Hankel determinants, Multivariate Gaussian approximation, Toeplitz determinants
HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-344577 (URN)10.1214/22-AIHP1332 (DOI)001177499400007 ()2-s2.0-85186940639 (Scopus ID)
Merknad

QC 20240321

Tilgjengelig fra: 2024-03-20 Laget: 2024-03-20 Sist oppdatert: 2024-04-26bibliografisk kontrollert
Courteaut, K., Johansson, K. & Lambert, G.From Berry-Esseen to super-exponential.
Åpne denne publikasjonen i ny fane eller vindu >>From Berry-Esseen to super-exponential
(engelsk)Manuskript (preprint) (Annet vitenskapelig)
Abstract [en]

For any integer $m<n$, where $m$ can depend on $n$, we study the rate of convergence of $\frac{1}{\sqrt{m}}\tr \mathbf{U}^m$ to its limiting Gaussian as $n\to\infty$ for orthogonal, unitary and symplectic Haar distributed random matrices $\mathbf{U}$ of size $n$. In the unitary case, we prove that the total variation distance is less than $\Gamma(\floor{n/m}+2)^{-1}m^{-\floor{n/m}}\floor{n/m}^{1/4}\sqrt{\log n}$ times a constant. This result interpolates between the super-exponential bound obtained for fixed $m$ and the $1/n$ bound coming from the Berry-Esseen theorem applicable when $m\ge n$ by a result of Rains. We obtain analogous results for the orthogonal and symplectic groups. In these cases, our total variation upper bound takes the form $\Gamma(2\floor{n/m}+1)^{-1/2}m^{-\floor{n/m}+1}(\log n)^{1/4}$ times a constant and the result holds provided $n \geq 2m$. For $m=1$, we obtain complementary lower bounds and precise asymptotics for the $L^2$-distances as $n\to\infty$, which show how sharp our results are. 

HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-326109 (URN)
Merknad

QCR 20230426

Tilgjengelig fra: 2023-04-24 Laget: 2023-04-24 Sist oppdatert: 2023-05-04bibliografisk kontrollert
Courteaut, K. & Johansson, K. Multivariate normal approximation for traces of orthogonal and symplectic matrices.
Åpne denne publikasjonen i ny fane eller vindu >>Multivariate normal approximation for traces of orthogonal and symplectic matrices
(engelsk)Manuskript (preprint) (Annet vitenskapelig)
Abstract [en]

We show that the distance in total variation between $(\tr U, \frac{1}{\sqrt{2}}\tr U^2, \cdots, \frac{1}{\sqrt{m}}\tr U^m)$ and a real Gaussian vector, where $U$ is a Haar distributed orthogonal or symplectic matrix of size $2n$ or $2n+1$, is bounded by $\Gamma(2\frac{n}{m}+1)^{-\frac{1}{2}}$ times a correction. The correction term is explicit and holds for all $n\geq m^4$, for $m$ sufficiently large. For $n\geq m^3$ we obtain the bound $(\frac{n}{m})^{-c\sqrt{\frac{n}{m}}}$ with an explicit constant $c$. Our method of proof is based on an identity of Toeplitz+Hankel determinants due to Basor and Ehrhardt, see \cite{BE}, which is also used to compute the joint moments of the traces.

HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-326107 (URN)
Merknad

QC 20230425

Tilgjengelig fra: 2023-04-24 Laget: 2023-04-24 Sist oppdatert: 2023-05-04bibliografisk kontrollert
Courteaut, K. & Johansson, K.Partition function for the 2d Coulomb gas on a Jordan curve.
Åpne denne publikasjonen i ny fane eller vindu >>Partition function for the 2d Coulomb gas on a Jordan curve
(engelsk)Manuskript (preprint) (Annet vitenskapelig)
Abstract [en]

We prove an asymptotic formula for the partition function of a 2d Coulomb gas at inverse temperature $\beta>0$ confined to lie on a Jordan curve. This also gives a central limit theorem for a linear statistic of the particles in the gas.  We obtain different expressions for the asymptotic mean and variance which involve either the exterior conformal mapping of the curve or the Grunsky operator.

HSV kategori
Identifikatorer
urn:nbn:se:kth:diva-326110 (URN)
Merknad

QCR 20230426

Tilgjengelig fra: 2023-04-24 Laget: 2023-04-24 Sist oppdatert: 2023-05-04bibliografisk kontrollert
Organisasjoner
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0003-1193-8355