Symmetry restoration and quantumness reestablishment

A realistic quantum many-body system, characterized by a generic microscopic Hamiltonian, is accessible only through approximation methods. The mean field theories, as the simplest practices of approximation methods, commonly serve as a powerful tool, but unfortunately often violate the symmetry of the Hamiltonian. The conventional BCS theory, as an excellent mean field approach, violates the particle number conservation and completely erases quantumness characterized by concurrence and quantum discord between different modes. We restore the symmetry by using the projected BCS theory and the exact numerical solution and find that the lost quantumness is synchronously reestablished. We show that while entanglement remains unchanged with the particle numbers, quantum discord behaves as an extensive quantity with respect to the system size. Surprisingly, discord is hardly dependent on the interaction strengths. The new feature of discord offers promising applications in modern quantum technologies.Comment: 17 pages and 3 figure

Historical Development in Education and Cultural Literacy of Chinese Tujia Working Songs in Chongqing

Chinese Tujia folk songs, deeply rooted in the cultural heritage of the Tujia ethnic group, serve as a living repository of history, values, and traditions. The primary objective of this study is to investigate the historical development of education and cultural literacy in Chinese Tujia working songs in Chongqing. The comprehensive literature review provides insights into the history of the Tujia ethnic group, their musical heritage, and contemporary challenges to preserving their cultural traditions. The research site includes Youyang Tujia and Miao Autonomous County, Shizhu Tujia Autonomous County, Pengshui Tujia, and Miao Autonomous County, and Qianjiang District. Key informants, including accomplished artists, academic researchers, and local experts, share their invaluable insights related to the preservation and performance of Tujia folk songs. By using the principles of music aesthetics, music ethnology, and ancient Chinese music history. The result of this study underscores the critical importance of preserving intangible cultural heritage, especially in the context of today’s rapid modernization and globalization. They highlight those traditional folk songs, like Chinese Tujia working songs, hold immense cultural and historical value. The study also provides actionable recommendations for ensuring the continued vitality of these culturally rich songs. These suggestions can guide efforts to integrate Tujia folk songs into educational curricula, support local musicians and artists, and promote cultural events

Robust creation of entanglement between remote memory qubits

In this Letter we propose a robust quantum repeater architecture building on the original DLCZ protocol [L.M. Duan \textit{et al.}, Nature \textbf{414}, 413 (2001)]. The architecture is based on two-photon Hong-Ou-Mandel-type interference which relaxes the long distance stability requirements by about 7 orders of magnitude, from sub wavelength for the single photon interference required by DLCZ to the coherence length of the photons. Our proposal provides an exciting possibility for robust and realistic long distance quantum communication.Comment: Comments are welcome, to appear in Phys. Rev. Lett., accepted versio

Fault-tolerant quantum repeater with atomic ensembles and linear optics

We present a detailed analysis of a new robust quantum repeater architecture building on the original DLCZ protocol [L.M. Duan \textit{et al.}, Nature (London) \textbf{414}, 413 (2001)]. The new architecture is based on two-photon Hong-Ou-Mandel-type interference which relaxes the long-distance interferometric stability requirements by about 7 orders of magnitude, from sub-wavelength for the single photon interference required by DLCZ to the coherence length of the photons, thereby removing the weakest point in the DLCZ schema. Our proposal provides an exciting possibility for robust and realistic long-distance quantum communication.Comment: Comments are welcome, to appear in Phys. Rev. A, accepted versio

The influence of minimum wage regulation on labor income share and overwork: evidence from China

Minimum Wage Regulation (MWR) can raise wage rate, but its relation with labor income share is in controversy. We explore the influence of raising wage rate on labor income share and overwork in China. Panel data regressions are taken mainly based on China’s Industrial Enterprise Database and the International Labor Organization Database. Our findings show that raising wage rate can increase labor income share without leading to overwork. Factors that may significantly increase overwork are a higher proportion of male workers, a larger income gap and a lower percapita income. We point out that the neoclassical explanation for labor income share is not persuasive. We support policies of raising wage rate and believe MWR is an effective measure to increase labor income share