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 24 2025, GMT+8
Location: Online
Zoom: https://nus-sg.zoom.us/j/89675000481?pwd=tDWM5CXGfAdPYd3ZexIpWwXx2Nx6bP.1
Password: 546550
Speaker: Leyna Shackleton
Title: Twisted quantum doubles are sign problem-free
Abstract: The sign problem is one of the central obstacles to efficiently simulating quantum many-body systems. It is commonly believed that some phases of matter, such as the double semion model, have an intrinsic sign problem and can never be realized in a local sign problem-free Hamiltonian due to the non-positivity of the wavefunction. We show that this is not the case. Despite failing to be stoquastic - the standard criteria for the existence of a sign problem - the double semion model as well as all twisted quantum double phases of matter for finite groups can be realized in local sign problem-free Hamiltonians. The lack of a sign problem is not fine-tuned and does not require the Hamiltonian to be exactly solvable, with sign problem-free perturbations allowing access to a variety of topological phase transitions.
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.