Theory of Quantum Crystals

Quantum Theory of Defects in Crystals

At sufficiently low temperatures localized defects or impurities change into excitations that move practically freely through a crystal. As a result instead of the ordinary diffusion of defects, there arises a flow of a liquid consisting of "defectons" and "impuritons." It is shown that at absolute zero in crystals with a large amplitude of the zero-point oscillations (for example, in crystals ...

Effective theory of incompressible quantum Hall liquid crystals

– I propose an effective theory of zero-temperature phases of the quantum Hall stripes: a smectic phase where the stripes are static and a novel quantum nematic phase where the positional order is destroyed by quantum fluctuations. The nematic is viewed as a Bose condensate of dislocations whose interactions are mediated by a U(1) gauge field. Collective mode spectrum and the dynamical structur...

Quantum theory of chiral interactions in cholesteric liquid crystals.

The effective chiral interaction between molecules arising from long-range quantum interactions between fluctuating charge moments is analyzed in terms of a simple model of chiral molecules. This model is based on the approximations that (a) the dominant excited states of a molecule form a band whose width is small compared to the average energy of excitation above the ground state and (b) biax...

Dynamics of Quantum Crystals

The phonon spectrum in a quantum crystal, where short-range correlations are important, is obtained by adapting the general relations between the onephonon response and the thermodynamic properties of an anharmonic crystal proposed by G6tze. Specifically, the one-phonon self-energy is obtained by requiring that the elastic constants obtained by the method of long waves equal those obtained as t...

Quantum pairing of impurities in quantum crystals.