I'm a postdoc at the Institute for Quantum Computing (IQC) at the University of Waterloo. Before that, I did my PhD at MIT (under Scott Aaronson), and a BMath and MMath (under Jeffrey Shallit) at the University of Waterloo.
My focus is on quantum complexity theory with recurring themes of
- Clifford circuits,
- low-depth circuits (classical and quantum), and
- classical simulation of quantum circuits.
My background is in discrete math: I've worked on combinatorial game theory, combinatorics on words (the subject of my Master's), and cellular automata.
- Classical algorithms for Forrelation
with Sergey Bravyi, David Gosset, and Daniel Grier.
- Interactive quantum advantage with noisy, shallow Clifford circuits
with Nathan Ju and Daniel Grier. Appeared in QIP 2021.
- Fast simulation of planar Clifford circuits
with David Gosset, Daniel Grier, and Alex Kerzner. Appeared in QIP 2021.
- Interactive shallow Clifford circuits: quantum advantage against NC1 and beyond
with Daniel Grier. Appeared in QIP 2020, presented in STOC 2020.
- Exponential separation between shallow quantum circuits and unbounded fan-in shallow classical circuits
with Adam Bene Watts, Robin Kothari, and Avishay Tal. Presented in QIP 2019, appeared in STOC 2019.
- A quantum query complexity trichotomy for regular languages.
with Scott Aaronson and Daniel Grier. Appeared in QIP 2019 and FOCS 2019.
- Trading T-gates for dirty qubits in state preparation and unitary synthesis
with Guang Hao Low and Vadym Kliuchnikov. Appeared in QIP 2020.
- New hardness results for the permanent using linear optics
with Daniel Grier. Appeared in CCC 2018.
- The classification of stabilizer operations over qubits
with Daniel Grier. Presented in QIP 2018.
- The classification of reversible bit operations
with Scott Aaronson and Daniel Grier. Appeared in ITCS 2017.
- A physically universal quantum cellular automaton.
Appeared in AUTOMATA 2015.
- A physically universal cellular automaton.
Best student paper in ITCS 2015.
I served as a teaching assistant for the following courses.
- Design and Analysis of Algorithms (MIT, Fall 2018)
- Geometric Computation (MIT, Spring 2018)
- Advanced Algorithms (MIT, Fall 2017)
- Introduction to the Theory of Computation (Waterloo)
- Algorithms (Waterloo)
email: lrschaeffer at gmail dot com