Replica Symmetry Breaking in Spin Glasses by Chandan Dasgupta

Explore the groundbreaking concept of Replica Symmetry Breaking in Spin Glasses in this 59-minute lecture by Chandan Dasgupta from the International Centre for Theoretical Sciences. Delve into the physics of interacting spin systems, frustration, and the Edwards-Anderson model. Examine the Sherrington-Kirkpatrick model and its limitations before uncovering the revolutionary Parisi solution. Understand the physical interpretation of Replica Symmetry Breaking, including ultrametricity and hierarchical structures in spin glass states. Learn about the Thouless-Anderson-Palmer equations and their significance. Discover how the Parisi solution explains experimental observations in real spin glasses and its implications for slow relaxation, hysteresis, and memory effects. Gain insights into the broader impact of this work, including applications in associative memory and content-addressable memory systems. The lecture concludes with a celebration of Giorgio Parisi's Nobel Prize-winning contributions to the field and a Q&A session.

Start
Replica Symmetry Breaking in Spin Glasses
Awarded the Nobel Prize in Physics, 2021
Interacting spin systems
For J 0, antiferromagnetic ordering may occur
What are Spin Glasses?
Experimental results: 1 Cusp in the magnetic susceptibility
Frustration
Edwards-Anderson Model
Spin Glass Phase
Edwards-Anderson Model
Magnetic susceptibility
The Sherrington-Kirkpatrick Model
S-K Model contd.
Replica Symmetry Breaking contd.
The Paris Solution
The Paris Solution contd.
Physical Interpretation of the Paris Solution
Thouless-Anderson-Palmer Equations
TAP Equations contd.
Physical interpretation of RSB G. Parisi, Phys Rev Lett 50, 1946 1983
Physical interpretation of RSB contd.
Ultrametricity: The valleys are arranged in a hierarchical tree-like 'ultrametric' structure
Predictions of the Paris solution have been confirmed from simulations.
Does the Paris solution explain experimentally observed behaviour in real spin glasses?
Dynamics: Slow relaxation, hysteresis, memory effects, aging, ...
Significance of the Paris Solution
Associative Memory: Retrieval of stored information from partial knowledge [content addressable memory]
Congratulations to Giorgio Parisi!
Q&A