Superconductivity and Conductivity of Hard Core Lattice Bosons

Note: 2 PM
Speaker: Assa Auerbach, Technion

When: February 16, 2010 (Tue), 02:00PM to 03:00PM (add to my calendar)

This event is part of the Condensed Matter Theory Seminar Series.

Abstract: Hard core bosons (HCB) near half filling, serve as a paradigm for strongly fluctuating superconductors with low superfluid density and lattice scale coherence length. The talk will concentrate on ‘unconventional’ features of HCB near half filling. The conductivity (both DC and AC) fall in the category of a `bad metal’ [1]. The temperature dependent order parameter exhibits a non-BCS trapezoidal shape [2]. The Hall conductivity changes sign abruptly about half filling, in contrast to any continuum superfluid. Precisely at half filling, vortices carry local spin-half (v-spin) degeneracies [3]. The phenomenology of HCB resembles some of the unusual characteristics of the normal state of cuprates. In particular, HCB yield a similar proportionality constant to the empirical ‘Homes law’ scaling.

[1] Netanel H. Lindner , Assa Auerbach, arXiv:0910.4158, Phys. Rev. B in press.
[2] Alexander Mihlin and Assa Auerbach, Phys. Rev. B 80, 134521 (2009).
[3] Netanel H. Lindner , Assa Auerbach and Daniel P. Arovas, Phys. Rev. Lett. 101, 070403 (2009).