Tue, March 10, 2026
3:45 pm - 4:45 pm
1080 Physics Research Building
Colloquium: Subir Sachdev, Harvard University
Many-fermion quantum entanglement in the high temperature superconductors and in black holes
Event Details:
- Date: March 10, 2026
- Time: 3:45 - 4:45 PM
- Location: 1080 Physics Research Building
- Faculty Host: Mohit Randeria
Abstract
Recent decades have seen remarkable progress in the theory of many-boson quantum entanglement, which has applications to quantum spin liquids in materials and devices, and connections to the theory of quantum error correction. But most modern quantum materials require the theory of many-fermion quantum entanglement, which has been less widely studied. I will describe two varieties of many-fermion entanglement, and their physical applications:
(A) the Fractionalized Fermi liquid (FL*), which predicted key features of recent measurements of the resistance in an applied magnetic field of the “pseudogap" phase of the cuprate high temperature superconductors.
(B) the Sachdev-Ye-Kitaev model, which has led to a computation of the low energy quantum density of states of charged black holes in asymptotically flat 3+1 dimensional space. Extensions of the SYK model also lead to a theory of the strange metal phase of the cuprates.
Bio
Subir Sachdev is Herchel Smith Professor of Physics at Harvard University. He has been elected to national academies of science in India and the US, and the Royal Society in the U.K. He is a recipient of several awards, including the Dirac Medal from the International Centre for Theoretical Physics, and the Lars Onsager Prize from the American Physical Society.
Sachdev has made extensive contributions to the theory of the diverse varieties of states of quantum matter, and of their behavior near quantum phase transitions.