Quantum coherence spectrum and quantum phase transitions
Yanchao Li, Jing Zhang, Hai‐Qing Lin
Abstract
We review the internal connection between quantum coherence (QC) and quantum phase transitions (QPTs). We propose two quantities ${L}_{\text{QC}}$ and ${S}_{\text{QC}}$ to detect QPTs of different orders by analyzing the spectrum of QC. Our results show that the two quantities not only can detect different types of QPT but can also exhibit a remarkable robustness against thermal fluctuations. In comparison with other detectors, such as quantum entanglement and QD, ${L}_{\text{QC}}$ and ${S}_{\text{QC}}$ can show more effective and reliable behaviors in characterizing a QPT at zero and finite temperatures. In light of this property and the fundamental role of QC in quantum information processing, QC spectrum-related ${L}_{\text{QC}}$ and ${S}_{\text{QC}}$ have considerable importance in detecting QPTs at a real finite-temperature experimental environment.