Volume 87, Number 1, July 2009
Article Number 10003
Number of page(s) 5
Section General
Published online 17 July 2009
EPL, 87 (2009) 10003
DOI: 10.1209/0295-5075/87/10003

Scaling dimension of fidelity susceptibility in quantum phase transitions

Shi-Jian Gu and Hai-Qing Lin

Department of Physics and ITP, The Chinese University of Hong Kong - Hong Kong, China

received 17 April 2009; accepted in final form 15 June 2009; published July 2009
published online 17 July 2009

We analyze ground-state behaviors of fidelity susceptibility (FS) and show that the FS has its own distinct dimension instead of real system's dimension in general quantum phases. The scaling relation of the FS in quantum phase transitions (QPTs) is then established on more general grounds. Depending on whether the FS's dimensions of two neighboring quantum phases are the same or not, we are able to classify QPTs into two distinct types. For the latter type, the change in the FS's dimension is a characteristic that separates two phases. As a non-trivial application to the Kitaev honeycomb model, we find that the FS is proportional to L2 ln L in the gapless phase, while L2 in the gapped phase. Therefore, the extra dimension of ln L can be used as a characteristic of the gapless phase.

03.67.-a - Quantum information.
64.60.-i - General studies of phase transitions.
75.10.Jm - Quantized spin models.

© EPLA 2009