Jeff (Sichao) Xu

jeffxusichao AT cmu DOT edu

I am a second year PhD student in the Theory Group at CMU, advised by Pravesh Kothari. Recently, I have spent most of my time thinking about convex relaxation hierarchies and their limitations, as well as the intersection of TCS and statistical physics.

Prior to CMU, I obtained my B.A. in Mathematics at UC Berkeley, where I had the fortune of working with Prasad Raghavendra. I am also grateful for the mentorship of Siu On Chan at CUHK.


Sum-of-Squares Lower Bounds for Sparse Independent Set.

with Chris Jones, Aaron Potechin, Goutham Rajendran, and Madhur Tulsiani.
To appear in FOCS 2021.

Certifying solution geometry in random CSPs: counts, clusters and balance. arxiv

with Jun-Ting Hsieh, and Sidhanth Mohanty.

Lifting Sum-of-Squares Lower Bounds: Degree-2 to Degree-4. arxiv

with Sidhanth Mohanty, and Prasad Raghavendra.
STOC 2020.

Teaching Experience:

CS170: Efficient Algorithms and Intractable Problems. (Fall 2018, Spring 2020).

Teaching Assistant

CS 174: Randomized Algorithms. (Spring, Fall 2019).

Head Teaching Assistant

I hope one day freedom and liberty will root in my country.