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Marcos Jardim

Publications and source records attributed to Marcos Jardim.

80 records · Page 5Linked to original sources
arXiv2002

A Fourier-Mukai approach to spectral data for instantons

We study U(r) instantons on elliptic surfaces with a section and show that they are in one-one correspondence with spectral data consisting of a curve in the dual elliptic surface and a line bundle on that curve. We use relative Fourier-Mukai transforms to analyse their properties and, in the case of the K3 and abelian surfaces, we show that the moduli space of instantons has a natural Lagrangian fibration with respect to the canonical complex symplectic structure.

math.AG↗
arXiv2002

Classification and existence of doubly-periodic instantons

We present a classification of SU(2) instantons on $T^2\times\mathbb{R}^2$ according to their asymptotic behaviour. We then study the existence of such instantons for different values of the asymptotic parameters, describing explicitly the moduli space for unit charge.

math.DG↗
arXiv2001

Spectral curves and Nahm transform for doubly-periodic instantons

We explore the role played by the spectral curves associated with Higgs pairs in the context of the Nahm transform of doubly-periodic instantons defined in "Construction of doubly-periodic instantons" (math.DG/9909069) and "Nahm transform for doubly-periodic instantons" (math.DG/9910120). More precisely, we show how to construct a triple consisting of an algebraic curve plus a line bundle with connection over it from a doubly-periodic instanton, and that these coincide with the Hitchin's spectral data associated with the Nahm transformed Higgs bundle.

math.AG↗
arXiv2000

Construction of doubly-periodic instantons

We construct finite energy instanton connection on $R^4$ which are periodic in two directions via an analogue of the Nahm transform for certain singular solutions of Hitchin's equations defined over a 2-torus.

math.DG↗
arXiv2000

Finite action solutions of SO(2,1) Hitchin's equations

We present a 1-parameter family of finite action solutions to the $S0(2,1)$ Hitchin's equations and explore some of its basic properties. For a fixed value of the parameter, the solution is smooth. We conclude by showing a multi-particle generalization of our basic solutions.

math-ph↗
arXiv2000

Asymptotic behaviour and the moduli space of doubly-periodic instantons

We study doubly-periodic instantons, i.e. instantons on the product of a 1-dimensional complex torus T with a complex line C, with quadratic curvature decay. We determine the asymptotic behaviour of these instantons, constructing new asymptotic invariants. We show that the underlying holomorphic bundle extends to TxP1. The converse statement is also true, namely a holomorphic bundle on TxP1 which is flat on the torus at infinity, and satisfies a stability condition, comes from a doubly-periodic instanton. Finally, we study the hyperkahler geometry of the moduli space of doubly-periodic instantons, and prove that the Nahm transform previously defined by the second author is a hyperkahler isometry with the moduli space of certain meromorphic Higgs bundles on the dual torus.

math.DG↗
arXiv1999

Nahm transform of doubly-periodic instantons

This work concerns the study of certain finite-energy solutions of the anti-self-dual Yang-Mills equations on Euclidean 4-dimensional space which are periodic in two directions, so-called doubly-periodic instantons. We establish a circle of ideas involving equivalent analytical and algebraic-geometric descriptions of these objects. In the first introductory chapter we provide an overview of the problem and state the main results to be proven in the thesis. In chapter 2, we study the asymptotic behaviour of the connections we are concerned with, and show that the coupled Dirac operator is Fredholm. After laying these foundations, we are ready to address the main topic of the thesis, the construction of a Nahm transform of doubly-periodic instantons. By combining differential-geometric and holomorphic methods, we show in chapters 3 through 5 that doubly-periodic instantons correspond bijectively to certain singular Higgs pairs, i.e. meromorphic solutions of Hitchin's equations defined over an elliptic curve. The circle of ideas is finally closed in chapter 8. We start by presenting a construction due to Friedman, Morgan and Witten that associates to each doubly-periodic instanton a spectral pair consisting of a Riemann surface plus a line bundle over it. On the other hand, it was shown by Hitchin that Higgs pairs are equivalent to a similar set of data. We show that the Friedman, Morgan and Witten spectral pair associated with a doubly-periodic instanton coincides with the Hitchin spectral pair associated with its Nahm transform. (This thesis contains the papers math.DG/9909069, math.DG/9910120 and math.AG/9909146.)

math.DG↗