Hi everyone,
For the next colloquium in this series, we are excited to have Matt Hastings (Microsoft Research), who will talk about sum-of-squares for fermionic systems and the SYK model. See details and calendar entry below.
The talk will take place on 28 February 2023, 4 pm London time.
Zoom link: https://maths-cam-ac-uk.zoom.us/j/95558689595?pwd=US9uSDlvdnFIVGJOZ3NKSzJpTTFEZz09
Best,
Tom and Sergii
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Matt Hastings (Microsoft Research)
Title: The sum-of-squares for fermionic systems, and the SYK model
Abstract: The central problem in physics and quantum chemistry is to determine properties of the ground state of an interacting system of fermions. As a quantum mechanical problem, there may be no efficient classical witness to the ground state energy, or even to an approximation of that energy. A commonly considered witness is a so-called "Gaussian state", or free fermion wavefunction. As a prominent example , the Sachdev-Ye-Kitaev (SYK) model has no Gaussian state which achieves a good approximation to the energy; this model is sometimes considered as one of the "most entangled" or "most strongly interacting" models possible. I will discuss applications of the sum-of-squares method to this model. Sum-of-squares is a semidefinite programming relaxation. I will show that this method can give classically efficient constant-factor lower bounds on the energy, and it inspires a quantum algorithm which gives constant-factor upper bounds. Joint work with R. O'Donnell.