Cassandra Marcussen

I am a Ph.D. student in theoretical computer science at Harvard University, advised by Madhu Sudan. In 2022, I graduated from Columbia University, where I double-majored in Mathematics and Computer Science and was advised by Xi Chen. My research is supported by an NDSEG Fellowship.

I am interested in theoretical computer science and probability theory. I like to think about problems related to sublinear algorithms, random graphs, error correction, and stochastic processes.

My email is cmarcussen-at-g-dot-harvard-dot-edu.

Research

Characterizing the Distinguishability of Product Distributions through Multicalibration [pdf].
Cassandra Marcussen, Aaron (Louie) Putterman, Salil Vadhan.
Computational Complexity Conference (CCC) 2025.

Finding the root in random nearest neighbor trees [pdf].
Anna Brandenberger, Cassandra Marcussen, Elchanan Mossel, Madhu Sudan.

Errors are Robustly Tamed in Cumulative Knowledge Processes [pdf].
Anna Brandenberger, Cassandra Marcussen, Elchanan Mossel, Madhu Sudan.
Conference on Learning Theory (COLT) 2024.
Proceedings of the National Academy of Sciences (PNAS) 2025.

Uniformity Testing over Hypergrids with Subcube Conditioning [pdf].
Xi Chen, Cassandra Marcussen.
Symposium on Discrete Algorithms (SODA) 2024.

Uniform scrambles on graphs [pdf].
Lisa Cenek, Lizzie Ferguson, Eyobel Gebre, Cassandra Marcussen, Jason Meintjes, Ralph Morrison, Liz Ostermeyer, Shefali Ramakrishna.
Australasian Journal of Combinatorics, 2023.

Scramble number and tree-cut decompositions [pdf].
Lisa Cenek, Lizzie Ferguson, Eyobel Gebre, Cassandra Marcussen, Jason Meintjes, Ralph Morrison, Liz Ostermeyer, Shefali Ramakrishna, Ben Weber.

Bounds on higher graph gonality [pdf].
Lisa Cenek, Lizzie Ferguson, Eyobel Gebre, Cassandra Marcussen, Jason Meintjes, Ralph Morrison, Liz Ostermeyer, Shefali Ramakrishna.
Presented at the Young Mathematicians Conference, 2021.

Data Preparation of the nuMoM2b Dataset [pdf].
A. Goretsky, A. Dmitrienko, I. Tang, N. Lari, O. Kunhardt, R. Rashid Khan, C. Marcussen, A. Catto, D. Mallia, A. Leshchenko, A. Lin, A. Raja, A. Salleb-Aouissi, Itsik Pe'er, R. Wapner, C. Gyamfi-Bannerman. (Non-alphabetical author ordering)
Technical report.

Authors are ordered alphabetically unless otherwise indicated.

Teaching

At Harvard:

Teaching Fellow for Essential Coding Theory (CS 229r) taught by Madhu Sudan (Fall 2023)

At Columbia, I was a Teaching Assistant for the following courses:

Advanced Algorithms (COMS 4232) taught by Alexandr Andoni (Spring 2022)
Introduction to Cryptography (COMS 4261) taught by Tal Malkin (Spring 2022)
Analysis of Algorithms I (CSOR 4251) taught by Xi Chen (Summer 2021) and Alexandr Andoni (Fall 2021)
Artificial Intelligence (COMS 4701) taught by Ansaf Salleb-Aouissi (Spring 2021)
Discrete Mathematics: Combinatorics and Graph Theory (COMS 3203) taught by Ansaf Salleb-Aouissi (Fall 2020)

Other:

TA for the PCMI Undergraduate Summer School on Quantum Computation (Summer 2023)
I lectured and served as a TA for the Undergraduate Math Society's Introduction to Proofs workshop (Fall 2020, Fall 2021)

Fellowships and Selected Awards

NDSEG Fellowship (2024)
NSF GRFP Fellowship (2024, declined in favor of NDSEG)
Magna cum laude, Columbia College (2022)
John Jay Scholar – Columbia University Scholars Program (2018 - 2022)
Verizon App Challenge: Best in Nation (2017)

Seminars and Organizations

I currently organize TGINF, a theory seminar for graduate students and postdocs at Harvard.
Columbia Undergraduate Learning Seminar in Theoretical Computer Science: Founder and Leader (Summer 2021 to Spring 2022). Organized reading groups on the analysis of Boolean functions and property testing (Summer 2021), A Theorist's Toolkit (Fall 2021), and High-Dimensional Probability and Applications to CS (Spring 2022).
Columbia-Barnard Association for Women in Mathematics: Co-President (2021-2022). Organized reading groups on random walks (Summer 2020) and topology (Summer 2021).

Axioms

I firmly believe Federico Ardila's axioms:

Axiom 1. Mathematical potential is equally present in different groups, irrespective of geographic, demographic, and economic boundaries.
Axiom 2. Everyone can have joyful, meaningful, and empowering mathematical experiences.
Axiom 3. Mathematics is a powerful, malleable tool that can be shaped and used differently by various communities to serve their needs.
Axiom 4. Every student deserves to be treated with dignity and respect.

Music

Outside of theoretical computer science and mathematics, one of my passions is music. I am a classical cellist, and I also play the piano and sing. I am currently learning the Bach Cello Suite No. 6 and Rachmaninoff's Sonata in G minor for Cello and Piano, Op. 19.