Department of Physics, National University of Singapore
Condensed Matter Seminar Series
To receive email notifications of this seminar series, please send an email to zouliujun@gmail.com to request.
Condensed Matter Seminar Series
To receive email notifications of this seminar series, please send an email to zouliujun@gmail.com to request.
Upcoming Seminars
(Both online and in-person seminars will be broadcast via Zoom.)
(Click the upper right corner of this page to see the previous seminars and their recordings.)
Time: 9am, October 17 2025, GMT+8
Location: Online
Zoom: https://nus-sg.zoom.us/j/89675000481?pwd=tDWM5CXGfAdPYd3ZexIpWwXx2Nx6bP.1
Password: 546550
Speaker: Leonardo Lessa
Title: Decohered but entangled: how symmetries and anomalies constrain mixed states
Abstract: Symmetries and their anomalies are among the most powerful non-perturbative tools to characterize quantum many-body systems. Traditionally, however, they have been limited to isolated systems, described by pure states. In this talk, we discuss how symmetries are a powerful constraint even when interactions with the environment are present. First, we show that topological order can survive as a long-range-entangled phase of matter even for mixed states. Crucially, this phase is characterized by emergent 1-form anomalous symmetries. Second, we address 0-form anomalies, which can appear at the boundary of SPT phases. There, we prove that strongly symmetric anomalous states exhibit long-range multipartite entanglement. Curiously, we find anomalous states possessing tripartite entanglement but no bipartite entanglement, an intrinsic feature of mixed states. Finally, if time permits, we discuss (non-anomalous) on-site symmetries. There, we find that thermal states with strong symmetries or superselection rules are generically entangled, which confirms previous results on specific symmetries and Hamiltonians.
Time: 9am, October 24 2025, GMT+8
Location: Online
Zoom: https://nus-sg.zoom.us/j/89675000481?pwd=tDWM5CXGfAdPYd3ZexIpWwXx2Nx6bP.1
Password: 546550
Speaker: Leyna Shackleton
Title: TBA
Abstract: TBA
Time: 9am, October 31 2025, GMT+8
Location: Online
Zoom: https://nus-sg.zoom.us/j/89675000481?pwd=tDWM5CXGfAdPYd3ZexIpWwXx2Nx6bP.1
Password: 546550
Speaker: Tomohiro Soejima
Title: TBA
Abstract: TBA
Time: 9am, November 7 2025, GMT+8
Location: Online
Zoom: https://nus-sg.zoom.us/j/89675000481?pwd=tDWM5CXGfAdPYd3ZexIpWwXx2Nx6bP.1
Password: 546550
Speaker: Kyle Kawagoe
Title: TBA
Abstract: TBA
Time: 9am, November 14 2025, GMT+8
Location: Online
Zoom: https://nus-sg.zoom.us/j/89675000481?pwd=tDWM5CXGfAdPYd3ZexIpWwXx2Nx6bP.1
Password: 546550
Speaker: Vladimir Calvera
Title: TBA
Abstract: TBA
The seminar series in the fall semester of 2025 is over, and the next seminar will take place in the spring semester of 2026.