Exact results for fidelity susceptibility of the quantum Ising model: the interplay between parity, system size, and magnetic field

Autor(en)

Bogdan Damski, Marek M. Rams

Abstrakt

We derive an exact closed-form expression for fidelity susceptibility of even- and odd-sized quantum Ising chains in a transverse field. To this aim, we diagonalize the Ising Hamiltonian and study the gap between its positive and negative parity subspaces. We derive an exact closed-form expression for the gap and use it to identify the parity of the ground state. We point out the misunderstanding in some of the former studies of fidelity susceptibility and discuss its consequences. Last but not least, we rigorously analyze the properties of the gap. For example, we derive analytical expressions showing its exponential dependence on the ratio between the system size and the correlation length.

Organisation(en)

Quantenoptik, Quantennanophysik und Quanteninformation

Externe Organisation(en)

Jagiellonian University in Krakow

Journal

Journal of Physics A: Mathematical and Theoretical

Band

47

Anzahl der Seiten

14

ISSN

1751-8113

DOI

https://doi.org/10.1088/1751-8113/47/2/025303

Publikationsdatum

01-2014

Peer-reviewed

Ja

ÖFOS 2012

103025 Quantenmechanik, 103029 Statistische Physik

Schlagwörter

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/cde0c688-8257-47f1-8578-e114623749d7