Abstract:
Quantum phase transitions (QPTs) refer to an abrupt change in the qualitative structure of the ground state wavefunction at absolute zero temperature when some external non-thermal parameters of the system vary. In the recent decade, the fidelity, which measures the similarity between two states, has become an attractive approach to study QPTs as the application of it does not require any a prior knowledge in the system’s symmetry. The fidelity and its susceptibility have been testified as a useful indicator to the quantum critical points in a number of condensed matter models. However, how to measure the fidelity in experiment and to extract information about a quantum phase from this approach are still challenging questions. In this talk, I will discuss our recent studies on these issues.