Vacuum superconductivity, conventional superconductivity and Schwinger   pair production
  In a background of a very strong magnetic field a quantum vacuum may turn into a new phase characterized by anisotropic electromagnetic superconductivity. The phase transition should take place at a critical magnetic field of the hadronic strength (B_c \approx 10^{16} Tesla or eB_c \approx 0.6 GeV^2). The transition occurs due to an interplay between electromagnetic and strong interactions: virtual quark-antiquark pairs popup from the vacuum and create -- due to the presence of the intense magnetic field -- electrically charged and electrically neutral spin-one condensates with quantum numbers of \rho mesons. The ground state of the new phase is a complicated honeycomblike superposition of superconductor and superfluid vortex lattices surrounded by overlapping charged and neutral condensates. In this talk we discuss similarities and differences between the superconducting state of vacuum and conventional superconductivity, and between the magnetic-field-induced vacuum superconductivity and electric-field-induced Schwinger pair production. 
M. N. Chernodub
hep-ph cond-mat.supr-con