Qihang Liu

Jul 10, 2024 | link.aps.org | jiayu Li |Ao Zhang |Yuntian Liu |Qihang Liu

In solid state systems, group representation theory is powerful in characterizing the behavior of quasiparticles, notably the energy degeneracy. While conventional group theory is effective in answering yes-or-no questions related to symmetry breaking, its application to determining the magnitude of energy splitting resulting from symmetry lowering is limited.

Jun 14, 2024 | opg.optica.org | Jung-Tsung Shen |Qihang Liu

Photon–photon correlations assume a pivotal significance in optical coherence. Recently, a new, to the best of our knowledge, type of quantum photonic states, the coherent state of photonic dimers, has been introduced, wherein the fundamental building blocks are two-photon bound states, instead of individual photons as in conventional lasers.

Nov 7, 2023 | link.aps.org | Qihang Liu |Yao Zhou |Jung-Tsung Shen

The concept of coherent states of single photons is generalized to the scenario wherein the fundamental building blocks are entangled two-photon states rather than single-photon states. To provide a concrete discussion, the case of photonic dimers (two-photon bound states) is explored. The coherent states of photonic dimers are defined. The correlation functions are calculated and expressed in terms of series expansion which is suitable for computational investigations.

May 19, 2023 | link.aps.org | Hongyi Sun |Qihang Liu

Abstract The anomalous Hall Effect (AHE) is one of the most fundamental phenomena related to band topology and holds great potential for technological applications. A promising approach to search for large AHE is to begin with a magnetic Weyl semimetal (WSM) and manipulate the Weyl nodes in the momentum-energy (k−E) space. However, controlling the Weyl points is generally difficult because Weyl nodes can robustly exist at a generic momentum.