凝聚态前沿论坛 （ 2018年12月21日星期五 下午）

      以铜氧高温超导为代表的强关联电子多体系统是凝聚态物理的重要研究对象，在长波低能下呈现许多新奇的演生现象。实验物理学家不断地发展ARPES（角分辨光电子能谱）、中子散射、STM等实验手段，探测材料学家制备的最新材料。同时，理论物理与数值计算专家在自旋-电荷分离理论、莫特物理、低能有效场论、维像理论、密度矩阵重整化群计算、蒙特卡洛计算等方面不断地向前推进。 近年来，随着实验手段的飞跃进步与理论物理学家的理论突破，在强关联电子多体系统，特别是铜氧和铁基超导体方面，学术界有了许多新的认识，比如关于费米弧和赝能隙的形成机制。为了促进中山大学物理学院在该研究领域的发展，我们举办首届凝聚态物理前沿前沿论坛，我院邀请到了国际上高温超导领域的资深专家——实验物理学家周兴江教授与理论物理学家翁征宇教授给大家介绍ARPES的最新实验与理论计算。本论坛鼓励报告人与听众的充分交流，不拘泥于形式。报告结束后，我们将有机会和专家们面对面交谈讨论前沿的学术进展以及学术人生、学术事业。

欢迎老师和学生踊跃参加！

14:30-15:40 实验进展学术报告（主持人：沈冰副教授）

地点：哲生堂三楼报告厅

题目: Laser ARPES on High Temperature Superconductors and Quantum Materials

报告人: 周兴江教授（中国科学院物理研究所研究员、超导国家重点实验室主任、美国物理学会会士）

摘要：The mechanism of high temperature superconductivity in the copper-based and iron-based superconductors remains a prominent and challenging issue in condensed matter physics. Angle-resolved photoemission spectroscopy (ARPES), as a powerful technique to directly probe the electronic structure of materials, has played a key role in studying high temperature superconductors. It also provides key insights on other quantum materials.  In this talk, I will first introduce the present status of high temperature superconductivity research, followed by a brief introduction on the latest development of photoemission techniques. Finally, I will highlight some of our recent results in utilizing the state-of-the-art laser-based ARPES to study the high temperature cuprate superconductors [1-3], iron-based superconductors [4-9], and other quantum materials [10-12].

[1] Yingying Peng et al., Nature Communications 4, 2459(2013).

[2] Junfeng He et al., Physical Review Letters 111, 107005 (2013).

[3] Jinmo Bok et al., Science Advances 2, e1501329 (2016).

[4] Defa Liu et al., Nature Communications 3, 931 (2012).

[5] Shaolong He et al., Nature Materials 12, 605 (2013).

[6] Xu Liu et al., Nature Communications 5, 5047 (2014).

[7] Junfeng He et al., PNAS 111, 18501 (2014).

[8] Lin Zhao et al., Nature Communications 7, 10608 (2016).

[9] Defa Liu et al., Phys. Rev. X 8, 031033 (2018)

[10] Zhuojin Xie et al., Nature Communications 5, 3382 (2014).

[11] Ya Feng et al., PNAS 133, 14656 (2016).

[12] Yan Zhang et al., Nature Communications 8, 15512 (2017).

15:40-15:50 Coffee Break

15:50-17:00 理论进展学术报告（主持人：叶鹏教授）

题目:  High-Temperature Superconductivity from the Perspective of Strong Correlation

报告人: 翁征宇教授（清华大学高等研究院杨振宁讲座教授、国家级人才项目学者、副院长）

摘要：High-temperature superconductivity in the cuprate remains one of the greatest challenges in condensed matter physics. It is widely believed to be a phenomenon of doped Mott insulators. In this talk, I will first review a unified picture for the Mottness based on a simplified model, i.e., the t-J model, where a novel sign structure in place of the conventional Fermi signs plays a fundamental role due to strong correlation. Then I will focus on the quasiparticle excitation and ARPES experiment as example to illustrate how such an effect leads to the Fermi arc, kinks in dispersion, quasiparticle weights in nodal and antinodal regimes, peak-hump-dip in EDC, and their systematic doping dependence in comparison with experiment in the pseudogap and superconducting phases. Finally, I will briefly mention variational calculations of the ground state wavefunction in comparison with other exact numerical results in the t-J model.   

17:00-17:30 自由讨论（主持人：钟定永教授）

地点：哲生堂四楼会议室