free site templates

Research

Research Interests


● Gauge theoretical moduli spaces in various dimensions, such as Seiberg-Witten theory, moduli spaces of Higgs bundles and character varieties, gauge theory and moduli spaces on foliated spaces.

● Applications of gauge theory to 4-manifolds including group actions and families.

● Mathematical physics, particularly geometric aspects of quantum field theory and string theory including: generalised geometry, T-duality and twisted K-theory.

Publications and Preprints


Preprints

[42] On the mapping class groups of simply-connected smooth 4-manifolds (2023) arXiv:2310.18819

[41] The mod 2 Seiberg-Witten invariants of spin structures and spin families (2023) arXiv:2303.06883

[40] Brieskorn spheres, cyclic group actions and the Milnor conjecture (with P. Hekmati) (2022) arXiv:2208.05143

[39] Knot concordance invariants from Seiberg-Witten theory and slice genus bounds in 4-manifolds (2022) arXiv:2205.11670

[38] The alpha invariant of complete intersections (2020) arXiv:2002.06750


Journal Articles

[37] An adjunction inequality obstruction to isotopy of embedded surfaces in 4-manifolds (2020), to appear in Mathematical Research Letters arXiv:2001.04006

[36] Equivariant Seiberg-Witten-Floer cohomology, to appear in Algebraic and Geometric Topology (with P. Hekmati) (2021) arXiv:2108.06855

[35] On the slice genus of quasipositive knots in indefinite 4-manifolds, Selecta Mathematica 29 (2023), no. 4, Paper No. 61 
arXiv:2204.09886 [published version]

[34] Non-trivial smooth families of K3 surfaces, Mathematische Annalen 387 (2023), no. 3-4, 1719–1744
arXiv:2102.06354 [published version]

[33] Tautological classes of definite 4-manifolds, Geometry and Topology, 27 (2023), no. 2, 641–698 arXiv:2008.04519 
[published version]

[32] A note on the Nielsen realization problem for K3 surfaces, Proceedings of the American Mathematical Society 151 (2023), no. 9, 4079–4087 (with H. Konno) arXiv:1908.03970 [published version]

[31] On the Bauer-Furuta and Seiberg-Witten invariants of families of 4-manifolds, Journal of Topology 15 (2022), no. 2, 505-586 (with H. Konno) arXiv:1903.01649 [published version] 

[30] A folitated Hitchin-Kobayashi correspondence, Advances in Mathematics 408 (2022), part B, Paper No. 108661, 47 pp. (with P. Hekmati) arXiv:1802.09699 [published version]

[29] Constraints on families of smooth 4-manifolds from Bauer-Furuta invariants, Algebraic and Geometric Topology 21 (2021) 317-349 arXiv:1907.03949 [published version]

[28] A gluing formula for families Seiberg-Witten invariants, Geometry and Topology 24 (2020) 1381-1456  (with H. Konno) arXiv:1812.11691 [published version]

[27] Obstructions to smooth group actions on 4-manifolds from families Seiberg-Witten theory, Advances in Mathematics 354 (2019), 106730, 32 pp. arXiv:1805.07860 [published version]

[26] Special Kähler geometry of the Hitchin system and topological recursion, Advances in Theoretical and Mathematical Physics 23 No. 8, 1981-2024 (with Z. Huang) (2017) arXiv:1707.04975 [published version]

[25] Cayley and Langlands type correspondences for orthogonal Higgs bundles, Transactions of the American Mathematical Society 371 (2019), no. 10, 7451-7492 (with L. Schaposnik) arXiv:1708.08828 [published version]

[24] On the image of the parabolic Hitchin map, The Quarterly Journal of Mathematics 69 (2018), no. 2, 681-708 (with M. Kamgarpour) arXiv:1703.09886 [published version]

[23] Complete integrability of the parahoric Hitchin system, International Mathematics Research Notices no. 21, 6499–6528 (with M. Kamgarpour and R. Varma) (2019) arXiv:1608.05454 [published version]

[22] Monodromy of the SL(n) and GL(n) Hitchin fibrations, Mathematische Annalen Vol. 370 (3) (2018), pp 1681-1716 arXiv:1612.01583 [published version]

[21] Monodromy of rank 2 twisted Hitchin systems and real character varieties, Transactions of the American Mathematical Society 370 (2018), 5491-5534 (with L. Schaposnik) arXiv:1506.00372 [published version]

[20] Arithmetic of singular character varieties and their E-polynomials, Proceedings of the London Mathematical Society (3) 114 (2017), no. 2, 293-332 (with P. Hekmati) arXiv:1602.06996 [published version]

[19] Classification of the automorphism and isometry groups of Higgs bundle moduli spaces, Proceedings of the London Mathematical Society (3) 112 (2016) 827-854 arXiv:1411.2228 [published version]

[18] Moduli spaces of Contact instantons, Advances in Mathematics 294 (2016) 562-595 (with P. Hekmati) arXiv:1401.5140 [published version]

[17] Automorphisms of C* moduli spaces associated to a Riemann surface, Symmetry, Integrability and Geometry: Methods and Applications (SIGMA), 12 (2016), 007, 14 pages (with I. Biswas and L. Schaposnik) arXiv:1508.06587 [published version]

[16] Transitive Courant algebroids, string structures and T-duality, Advances in Theoretical and Mathematical Physics Vol 19 No. 3, 613-672 (2015) (with P. Hekmati) arXiv:1308.5159 [published version]

[15] Cyclic Higgs bundles and the affine Toda equations, Geometriae Dedicata Vol. 174 (2015), pp 25-42 arXiv:1011.6421 [published version]

[14] A Fourier Mukai approach to the K-theory of compact Lie groups, Advances in Mathematics 269 (2015), pp. 335-345 (with P. Hekmati) arXiv:1406.3993 [published version]

[13] Real structures on moduli spaces of Higgs bundles, Advances in Theoretical and Mathematical Physics Vol 20 No. 3, 525-551 (2016) (with L. Schaposnik) arXiv:1309.1195 [published version]

[12] Higgs bundles and (A,B,A)-branes, Communications in Mathematical Physics 331 (2014), no. 3, 1271-1300 (with L. Schaposnik) arXiv:1305.4638 [published version]

[11] A coboundary morphism for the Grothendieck spectral sequence, Applied Categorical Structures 22 pp. 269-288 (2014) arXiv:1112:6295 [published version]

[10] Topological T-duality for general circle bundles, Pure and Applied Mathematics Quaterly Vol. 10, no. 3, pp. 367-438 (2014) arXiv:1105:0290 [published version]

[9] Variation of Hodge structure for generalized complex manifolds, Differential Geometry and its Applications 36 (2014), pp. 98-133 arXiv:1205.0240 [published version]

[8] Topological T-duality for torus bundles with monodromy, Reviews in Mathematical Physics 27, No. 3 (2015), 1550008 arXiv:1201.1731 [published version]

[7] Conformal Courant algebroids and orientifold T-duality, International Journal of Geometric Methods in Modern Physics Vol 10, no. 2 (2013), 1250084 arXiv:1109.0875 [published version]

[6] Leibniz algebroids, twistings and exceptional generalized geometry, Journal of Geometry and Physics 62 (2012), pp. 903-934 arXiv:1101.0856 [published version]

[5] Moduli of Coassociative Submanifolds and Semi-Flat G2-manifolds, Journal of Geometry and Physics 60 (2010), pp. 1903-1918 arXiv:0902.2135 [published version]

Book Chapters

[4] Introduction to Generalized Geometry and T-duality, in Open Problems and Surveys of Contemporary Mathematics SMM 6, pp. 45-97 (2013)

This book chapter is an introduction to generalized geometry, T-duality and twisted K-theory. In writing this paper one of the main objectives was to explain how these topics fit together as part of a bigger picture: these topics are aspects of the geometry underlying string theory.

Conference Papers

[3] Brauer group of moduli of Higgs bundles and connections, to appear in Hitchin 70 proceedings, Oxford University Press (with I. Biswas and L. Schaposnik) (2017) arXiv:1609.00454

[2] Topological T-duality with monodromy, String-Math 2011, Proceedings of Symposia in Pure Mathematics, Eds. J. Block, J. Distler, R. Donagi, E. Sharpe, (2012), vol 85, pp. 293-302 [link to AMS bookstore] [String-Math 2011 webpage]

This is a summary of my research on topological T-duality for torus bundles with monodromy.

DPhil Thesis

[1] G2 Geometry and Integrable Systems, arXiv:1002.1767

My thesis studied some appearances of the exceptional Lie group G2 in geometry and integrable systems. In more detail, my thesis consists of three topics:

1. We study the Hitchin component in the space of representations of the fundamental group of a Riemann surface into a split real simple Lie group in the rank 2 case. We prove that such representations are described by a conformal structure and class of Higgs bundle we call cyclic and we show cyclic Higgs bundles correspond to a form of the affine Toda equations. In each case we relate cyclic Higgs bundles to geometric structures on the surface.

2. We elucidate the geometry of generic 2-plane distributions in 5 dimensions, relating it to a parabolic geometry associated to the split real form of G2 and a conformal geometry with holonomy in G2. We prove the distribution is the bundle of maximal isotropics corresponding to the annihilator of a spinor satisfying the twistor-spinor equation.

3. We study the moduli space of coassociative submanifolds of a G2-manifold with an aim towards understanding coassociative fibrations. We consider coassociative fibrations where the fibres are orbits of a torus action of isomorphisms and prove a local equivalence to minimal 3-manifolds in R^{3,3} with positive induced metric.