The magnetic field of these objects can be described using the London equations, and they can be described mathematically with the Ginzburg-Landau theory. One theory describing them notes that electrons below the Fermi level 
The magnetic field of these objects can be described using the London equations, and they can be described mathematically with the Ginzburg-Landau theory. One theory describing them notes that electrons below the Fermi level can bind together to form Cooper pairs. YBCO is notable for acting as one of these materials above the boiling point of nitrogen. These materials experience an expulsion of their magnetic field in a phenomenon known as the Meissner effect and can be described by the BCS theory. For 10 points, name this type of material, which as its name suggests has an electrical resistivity of zero.
The magnetic field of these objects can be described using the London equations, and they can be described mathematically with the Ginzburg-Landau theory.
{superconductor}