About

I am a third-year computer science Ph.D. student at the University of Chicago studying quantum computer systems with Fred Chong. Previously, I graduated from Carnegie Mellon University in 2022 with a B.S. in physics and a minor in computer science.

I believe that co-designing quantum hardware and quantum error correction is essential to make scalable quantum computing a reality. I am currently working on tailoring QEC to hardware and improving real-time decoding. Previously, I have published work on software mitigation of time-varying noise (such as cosmic ray impacts and shifting two-level system defects) in the surface code, quantum control pulse optimization, and a pair of papers on compiling with ququarts.

In the summer of 2024, I interned with the quantum computing team at Intel, where I created integrated tools for QEC-informed exploration of the spin qubit design space, providing guidance for Intel’s quantum roadmap. Stay tuned for an upcoming publication!

Research

Short two-qubit pulse sequences for exchange-only spin qubits in 2D layouts
(under review)
Jason D. Chadwick, Gian Giacomo Guerreschi, Florian Luthi, Mateusz T. Mądzik, Fahd A. Mohiyaddin, Prithviraj Prabhu, Albert T. Schmitz, Andrew Litteken, Shavindra Premaratne, and Nathaniel Bishop

[project] [.pdf] [arXiv]

We present a library of two-qubit pulse sequences for EO qubits in different 2D configurations. We explore the impact of EO qubit topology on quantum error correction performance.

SWIPER: Minimizing Fault-Tolerant Quantum Program Latency via Speculative Window Decoding
(under review)
Joshua Viszlai*, Jason D. Chadwick*, Sarang Joshi, Gokul Ravi, Yanjing Li, and Frederic T. Chong

[project] [.pdf] [arXiv]

We translate branch prediction from classical architecture to the problem of windowed decoding of quantum-error-corrected algorithms. We show that this can consistently reduce application benchmark runtimes by 40%.

* indicates equal contribution

QSYS Best Paper - 1st place
Averting multi-qubit burst errors in surface code magic state factories
QCE 2024
Jason D. Chadwick, Christopher Kang, Joshua Viszlai, Sophia Fuhui Lin, and Frederic T. Chong

[project] [.pdf] [arXiv] [talk] [slides] [code]

We design an efficient method to avoid cosmic ray errors in magic state factories, significantly reducing the qubitcycle cost of mitigating these errors.

Dynamic mitigation of time-varying noise in surface code magic state factories
(in preparation)
Jason D. Chadwick*, Christopher Kang*, Sophia Fuhui Lin, and Frederic T. Chong

[project] [slides]

We show that surface code magic state factories are vulnerable to varying hardware performance and can magnify hardware degradation. To alleviate this problem, we introduce Verity, a resilient kernel for magic state distillation.

* indicates equal contribution

QTEM Best Paper - 3rd place
Efficient control pulses for continuous quantum gate families through coordinated re-optimization
QCE 2023
Jason D. Chadwick and Frederic T. Chong

[project] [.pdf] [publication] [arXiv] [talk] [poster] [code]

We present a method that allows quantum hardware to execute arbitrary operations at the pulse level by interpolating between a small number of known reference pulses. We demonstrate the procedure on the continuous space of all two-qubit operations.

Dancing the Quantum Waltz: Compiling Three-Qubit Gates on Four Level Architectures
ISCA 2023
Andrew Litteken, Lennart Maximilian Seifert, Jason D. Chadwick, Natalia Nottingham, Tanay Roy, Ziqian Li, David Schuster, Jonathan M. Baker, and Frederic T. Chong

[project] [.pdf] [publication] [arXiv]

We extend our previous work on qubit-to-ququart compression to specifically optimize three-qubit gates such as the Toffoli gate. We also find significant advantages in using Z-type multi-bit operations instead of X-type operations.

Qompress: Efficient Compilation for Ququarts Exploiting Partial and Mixed Radix Operations for Communication Reduction
ASPLOS 2023
Andrew Litteken, Lennart Maximilian Seifert, Jason D. Chadwick, Natalia Nottingham, Jonathan M. Baker, and Frederic T. Chong

[project] [.pdf] [publication] [arXiv]

We consider selectively compressing pairs of qubits into single four-state ququarts. We generate efficient "partial" operations between ququarts and qubits, which motivates a compiler that can transform any quantum circuit into this framework.

Time-Efficient Qudit Gates through Incremental Pulse Re-seeding
QCE 2022
Lennart Maximilian Seifert*, Jason D. Chadwick*, Andrew Litteken, Frederic T. Chong, and Jonathan M. Baker

[project] [.pdf] [publication] [arXiv] [poster]

We present a method to iteratively obtain short-duration quantum control pulses when it is not possible to directly modify the objective function. We use this to find gate durations for high-radix logic gates that scale better than expected.

* indicates equal contribution

Prediction of electron density and pressure profile shapes on NSTX-U using neural networks
Nuclear Fusion 61 046024
Mark D. Boyer and Jason D. Chadwick

[project] [.pdf] [publication] [poster] [slides]

We develop a neural network to accurately predict cross-sectional shapes of plasma density and pressure on the NSTX-U fusion reactor. The network runs orders of magnitude faster than existing physics-based code.

Projects

qc_utils

[code]

Collection of useful utility functions that I have accumulated while working on various quantum computing projects. Includes flexible state/process tomography experiments, Hamiltonian builders, many quantum logic gates, and more miscellaneous reuseable code.

Chronodrifter

[project] [live web game] [code]

A 2D platformer game where the player can slow and reverse the flow of time to solve increasingly complex puzzles. Inspired by the game Portal and the movie Tenet. A live web version is hosted on this site. Made with Unity and C#.

Quops

[project] [code]

A board game consisting of hexagonal tiles, with each tile corresponding to a qubit. Players take turns applying quantum operations to the board to try to steer the collective board state to their target state. Graphical edition coming soon!

Cosmic string loops

[project]

In the summer of 2019, I worked with Ken Olum at the Tufts Institute of Cosmology to study the properties of smooth cosmic string loops. I began the summer running computational simulations of cosmic strings and later transitioned to working on a mathematical proof that smooth cosmic string loops will always decay.

Miscellaneous

Unresolved Research Ideas

[page]

A collection of research ideas I have tried and have not had success with - because science should encourage dissemination of negative results more!

Last Minute

[concert video (YouTube)]

In my junior year of undergrad, some friends and I created a makeshift band to fill an open spot in CMU's annual Spring Carnival. Because we formed the band two weeks before the show date, we chose the fitting name "Last Minute". I'm all the way on stage left playing rhythm guitar! Check out 42:20 for some improvised solos at the end.