Speaker: Subir Sachdev Harvard University
Time: 2024-07-18 10:30-2024-07-18 12:00
Venue: FIT 1-315

Abstract:

Quantum spin liquid states have been intensively studied over the past three decades for spin Hamiltonians on the square lattice with short-range interactions which preserve global spin rotation symmetry. Many new theoretical ideas have been developed on this journey, and I will summarize the current understanding.

I will then describe how the theory of quantum spin liquids can be extended to include a finite density of mobile charge carriers, and compare results to studies of the fermionic Hubbard model by ultracold atoms. I will also argue that a particular gapless spin liquid state helps us understand several puzzling features of the cuprate phase diagram.

Short Bio:

Subir Sachdev is Herchel Smith Professor of Physics at Harvard University. Sachdev has made extensive contributions to the theory of the diverse varieties of quantum matter, and of their behavior near quantum phase transitions. Many of these contributions have been linked to experiments, especially to the rich phase diagrams of the copper-oxide high temperature superconductors. Sachdev's research has also exposed remarkable connections between the nature of multi-particle quantum entanglement in certain laboratory materials, and the quantum entanglement in black holes, and these connections have led to new insights on the entropy and radiation of black holes.

Sachdev has been elected to national academies of science in the United States and India, and to the Royal Society in the U.K. He is a recipient of several awards, including the Dirac Medal from ICTP, and the Lars Onsager Prize from the American Physical Society.