Bipolarons in homogeneous DNA duplexes

Numerical calculations using the Holstein–Hubbard model show that stable bipolarons can form in homogeneous DNA duplexes. Since matrix elements of the Hamiltonians are different, the phase diagram determining the bipolarons stability for a G/C duplex differs from that for an A/T duplex. It is shown that a bipolaron superconductivity with the transition temperature Tc = 6 – 20 K can take place in DNA, and the transition temperature depends on the parameter values of the model. The bipolaron model can serve as a basis for explaining experiments on DNA superconductivity.