Quantum theory of a nematic Fermi fluid - art. no. 195109

We develop a microscopic theory of the electronic nematic phase proximate t o an isotropic Fermi liquid in both two and three dimensions. Explicit expr essions are obtained for the small amplitude collective excitations in the ordered stated remarkably, the nematic Goldstone mode (the director wave) i s overdamped except along special directions dictated by symmetry. At the q uantum critical point we find a dynamical exponent of z = 3, implying stabi lity of the Gaussian fixed point. The leading perturbative effect of the ov erdamped Goldstone modes leads to a breakdown of Fermi-liquid theory in the , nematic phase and to strongly angle-dependent electronic self energies ar ound the Fermi surface. Other metallic liquid-crystal phases, e.g., a quant um hexatic, behave analogously.