1305.6125 (Sergei I. Mukhin)

Instantonic condensates in many-body systems: breakdown of Goldstone's
theorem    [PDF]

Sergei I. Mukhin

It is demonstrated that quantum ordering in the system with global continuous symmetry contrary to the case of classical ordering, that is characterized with emergence of a mean-field order parameter, does not cause necessarily appearance of massless Goldstone bosons (i.e. gapless Goldstone modes). It is demonstrated that the theorem can be violated, i.e. the Goldstone modes possess finite gap in the case of a quantum ordered state of interacting fermions. This result may lead to important consequences when considered in combination with another peculiar properties of the QOP state found recently {mukhin 2011}: {\it{QOP does not scatter anything in Minkowski world}}! Hence, the present theory, we believe, may naturally indicate that two effects: "hidden order" revealed in ARPES spectra of fermi-excitations and "neutron resonance" feature at finite frequency in the magnetic (bosonic) excitations spectrum in lightly hole-doped copper oxides, could be emerging fingerprints of the QOP state. A peculiar manifestation of the QOP self-consistent solution is also predicted for a photon field coupled with the array of Josephson junctions in the superconducting resonator cavity. It is demonstrated that it constitutes merely a metastable state of the system, that, for a particular quantum disordering model, exists inside the stability domain of the classical photonic condensate delimited by the critical value of the quantum disordering strength.

View original: http://arxiv.org/abs/1305.6125