Capacity of a multiply-connected domain and nonexistence of   Ginzburg-Landau minimizers with prescribed degrees on the boundary
  Suppose that $\omega\subset\Omega\subset R^2$. In the annular domain $A=\Omega\setminus\bar\omega$ we consider the class $J$ of complex valued maps having degree 1 on $\partial \Omega$ and on $\partial\omega$.   It was conjectured by Berlyand and Mironescu ('04), that he existence of minimizers of the Ginzburg-Landau energy $E_\kappa$ in $J$ is completely determined by the value of the $H^1$-capacity $cap(A)$ of the domain and the value of the Ginzburg-Landau parameter $\kappa$.   The existence of minimizers of $E_\kappa$ for all $\kappa$ when $cap(A)\geq\pi$ (domain $A$ is ``thin'') and for small $\kappa$ when $cap(A)<\pi$ (domain $A$ is ``thick'') was established by Berlyand and Mironescu ('04).   Here we provide the answer for the remaining case of large $\kappa$ when $cap(A)<\pi$. We prove that, when $cap(A)<\pi$, there exists a finite threshold value $\kappa_1$ of the Ginzburg-Landau parameter $\kappa$ such that the minimum of the Ginzburg-Landau energy $E_\kappa$ is not attained in $J$ when $\kappa>\kappa_1$ while it is attained when $\kappa<\kappa_1$. 
Leonid Berlyand (Pennsylvania State University), Dmitry Golovaty   (University of Akron), and Volodymyr Rybalko (Institute f...