About

My name is Jielun Chen (陈捷伦), and I also go by Chris. I’m a Ph.D. student at Caltech, advised by Prof. Garnet Chan and Prof. John Preskill.

My research aims to find practical quantum advantages in simulating molecules and materials. We recently developed a framework for polynomial quantum speedups under the same approximations used in classical electronic-structure methods.

I also aim to understand the classical–quantum boundary through tensor-network simulations, such as how sign structure affects the difficulty of contracting tensor networks, and what quantum-inspired tensor-network algorithms can do.

Before Caltech, I earned B.S. degrees in physics and computer science at UC Irvine in 2022, where I worked with Prof. Steve White on tensor-network methods and with Prof. Kieron Burke on density functional theory.

Updates

• Sep 2026 — Our work on robust quantum speedups for electronic structure and dynamics was accepted in Physical Review Letters.
• Dec 2025 — We posted a preprint on a polynomial-time algorithm for weakly interacting fermions.
• Dec 2025 — Calbee Quantum, our team led by Garnet Chan, was selected as one of seven XPRIZE Quantum Applications finalists.

Recent Papers

1. Convergence of the cumulant expansion and polynomial-time algorithm for weakly interacting fermions
   Hongrui Chen, Cambyse Rouzé, Jielun Chen, Jiaqing Jiang, Samuel O. Scalet, Yongtao Zhan, Garnet K. Chan, Lexing Ying, Yu Tong
   [arXiv:2512.12010]
2. Framework for robust quantum speedups in practical correlated electronic structure and dynamics
   Jielun Chen, Garnet K. Chan
   [Phys. Rev. Lett. 2026][arXiv:2508.15765] [XPRIZE Finalist]
3. Quantum linear algebra for disordered electrons
   Jielun Chen, Garnet K. Chan
   [arXiv:2411.00434]
4. Positive bias makes tensor-network contraction tractable
   Jiaqing Jiang, Jielun Chen, Norbert Schuch, Dominik Hangleiter
   [QIP 2025] [STOC 2025] [arXiv:2410.05414]
5. Sign problem in tensor network contraction
   Jielun Chen, Jiaqing Jiang, Dominik Hangleiter, Norbert Schuch
   [PRX Quantum 2025] [arXiv:2404.19023]
6. Direct interpolative construction of the discrete Fourier transform as a matrix product operator
   (alphabetical order) Jielun Chen, Michael Lindsey
   [ACHA][arXiv:2404.03182]
7. Quantum Fourier transform has small entanglement
   Jielun Chen, E.M. Stoudenmire, Steven R. White
   [PRX Quantum 2023] [arXiv:2210.08468]

Talks

(slides may not include the latest updates)

• A framework for robust quantum speedups in practical correlated electronic structure and dynamics
  • Kaifeng Bu group meeting, Ohio State University, Nov. 2025
  • AWS quantum algorithm meeting, Pasadena, Sep. 2025
• Complexity of slightly positive tensor networks
  • Center for Computational Quantum Physics at Simons Foundation, New York, Apr. 2025 (slides)
  • QIP 2025, Raleigh, Feb. 2025 (slides) (video)
  • APS March Meeting, Anaheim, Mar. 2025
  • Tensor Network Weekly Meeting hosted by Guifré Vidal, June 2024 (slides)
• Quantized Tensor Train
  • UC Berkeley / Lawrence Berkeley Laboratory Applied Mathematics Seminar, Berkeley, Oct. 2023 (slides)
• Quantum Fourier transform has small entanglement
  • Yuehaw Khoo group meeting, University of Chicago, Feb. 2024 (slides)
  • APS March Meeting, Las Vegas, Mar. 2023
  • Quantum Colloquium, Simons Institute for the Theory of Computing, Berkeley, Mar. 2023 (slides) (video)
  • Quantum lunch seminar, Los Alamos National Lab, Feb. 2023
  • Tensor Network Weekly Meeting hosted by Guifré Vidal, Nov. 2022
  • Symposium on New Developments in Tensor Networks and Quantum Computation, Flatiron Institute & Initiative for Theoretical Sciences, New York, Nov. 2022