Bubbling analysis of a conformal heat flow for harmonic maps

Woongbae Park

We study a conformal heat flow for harmonic maps. It is known that global weak solution of the flow exists and smooth except at mostly finitely many singular points. In this paper, we conduct a bubbling analysis for a finite time singularity.

The Yang-Mills-Higgs functional on complex line bundles: asymptotics for critical points
Giacomo Canevari, Federico Luigi Dipasquale, Giandomenico Orlandi
We consider a gauge-invariant Ginzburg-Landau functional (also known as Abelian Yang-Mills-Higgs model) on Hermitian line bundles over closed Riemannian manifolds of dimension n≥3. Assuming a logarithmic energy bound in the coupling parameter, we study the asymptotic behaviour of critical points in the non-self dual scaling, as the coupling parameter tends to zero. After a convenient choice of the gauge, we show compactness of finite-energy critical points in Sobolev norms. Moreover,

Continuous in time bubble decomposition for the harmonic map heat flow
Jacek Jendrej, Andrew Lawrie, Wilhelm Schlag
We consider the harmonic map heat flow for maps from the plane to the two-sphere. It is known that solutions to the initial value problem exhibit bubbling along a well-chosen sequence of times. We prove that every sequence of times admits a subsequence along which bubbling occurs. This is deduced as a corollary of our main theorem, which shows that the solution approaches the family of multi-bubble configurations in continuous time.

DIRECT MINIMIZING METHOD FOR YANG-MILLS ENERGY OVER SO(3) BUNDLE
In this paper, we use the direct minimizing method to find Yang- Mills connections for SO(3) bundles over closed four manifolds. By constructing test connections, we prove that a minimizing sequence converges strongly to a minimizer under certain assumptions. In case the strong convergence fails, we find an anti-selfdual (or selfdual) connection.

ON THE BLOW-UP OF YANG-MILLS FIELDS IN DIMENSION FOUR
In this paper, we study the blow-up of a sequence of Yang-Mills connection with bounded energy on a four manifold. We prove a set of equations relating the geometry of the bubble connection at the infinity with the geometry of the limit connection at the energy concentration point. These equations exclude certain scenarios from happening, for example, there is no sequence of Yang-Mills SU(2) connections on S4 converging to an ASD one- instanton while developing a SD one-instanton as a bubble. The proof involves the expansion of connection forms with respect to some Coulomb gauge on long cylinders.