Dimensionality and Criticality in Strongly-Correlated Materials

Can Shao, Hantao Lu, Xiao Zhang +3 more

By employing the exact diagonalization method, we investigate the high-harmonic generation (HHG) of the correlated systems under the strong laser irradiation. For the extended Hubbard model on a periodic chain, HHG close to the quantum critical point (QCP) is more significant compared to two neighboring gapped phases (i.e., charge-density-wave and spin-density wave states), especially in low frequencies. We confirm that the systems in the vicinity of the QCP are supersensitive to the external field and more optical-transition channels via excited states are responsible for HHG. This feature holds the potential of obtaining high-efficiency harmonics by making use of materials approaching QCP. Based on the two-dimensional Haldane model, we further propose that the even- or odd-order components of generated harmonics can be promisingly regarded as spectral signals to distinguish the topologically ordered phases from locally ordered ones. Our findings in this Letter pave the way to achieve ultrafast light source from HHG in strongly correlated materials and to study quantum phase transition by nonlinear optics in strong laser fields.

Seongmin Kim, In-Saeng Suh, Travis S. Humble +3 more

Developing high-performance materials is critical for diverse energy applications to increase efficiency, improve sustainability and reduce costs. Classical computational methods have enabled important breakthroughs in energy materials development, but they face scaling and time-complexity limitations, particularly for high-dimensional or strongly correlated material systems. Quantum computing (QC) promises to offer a paradigm shift by exploiting quantum bits with their superposition and entanglement to address challenging problems intractable for classical approaches. This perspective discusses the opportunities in leveraging QC to advance energy materials research and the challenges QC faces in solving complex and high-dimensional problems. We present cases on how QC, when combined with classical computing methods, can be used for the design and simulation of practical energy materials. We also outline the outlook for error-corrected, fault-tolerant QC capable of achieving predictive accuracy and quantum advantage for complex material systems.

Angela Kopp, Sudip Chakravarty

Rishabh Jha

佳史 守田

Noel COPINET

Recent experimental observations have revealed the emergence of a topological state withina quantum critical regime, in a system where the description in terms of electronic quasiparticlesis no longer valid. Such a result is often presented as paradoxical from the viewpointof standard theoretical frameworks of condensed matter physics. In this work, we demonstraterigorously that this phenomenon is fully compatible with a five-dimensional geometricframework, in which topological properties are global invariants independent of any effectivefour-dimensional particle-based reduction. Our analysis relies exclusively on general structuralarguments and does not require any ad hoc assumption or material-specific adjustment.