Fully frustrated one-dimensional diamond Josephson chains have been shown [B. Dou\\\\c{c}ot and J. Vidal, Phys. Rev. Lett. {\\\\bf 88}, 227005 (2002)] to posses a remarkable property: The superfluid phase occurs through the condensation of pairs of Cooper pairs. By means of Monte Carlo simulations we analyze quantitatively the Insulator to $4e$-Superfluid transition. We determine the location of the critical point and discuss the behaviour of the phase-phase correlators. For comparison we also present the case of a diamond chain at zero and 1/3 frustration where the standard $2e$-condensation is observed.

%B Phys. Rev. B 73 (2006) 100502(R) %G en_US %U http://hdl.handle.net/1963/2400 %1 2297 %2 Physics %3 Condensed Matter Theory %$ Submitted by Andrea Wehrenfennig (andreaw@sissa.it) on 2007-11-13T08:27:31Z\\nNo. of bitstreams: 1\\n0511423v1.pdf: 197406 bytes, checksum: 754c3576bbb6a549f4dac12eeb8fc92d (MD5) %R 10.1103/PhysRevB.73.100502