Todd Brun
University of Southern California, CA·Physics
Quantum computers could tackle problems that overwhelm ordinary computers, such as simulating molecules or finding the best solution among many options. Quantum information is fragile, though: qubits, the quantum version of bits, lose their information to noise from their surroundings, a problem called decoherence.
- Fields
Physics
Computer Science
Engineering
- Topics
quantum error correction
fault-tolerant quantum computing
error-detecting codes
- Grants
- 2 known grants, through Jun 2027
What they work on
- Develop weakly fault-tolerant quantum computing using error-detecting codes that store n–2 logical qubits in n physical qubits, detecting single faults and discarding runs that show errors, for use on near-term processors.
- Prepare and verify ancilla (helper) states for teleportation-based protected computing in a single combined step, using flag qubits that signal spreading errors together with error detection.
- Design fast, accurate decoders for quantum error-correcting codes using machine learning, so errors can be identified in real time during a quantum computation.
- Test whether quantum field theories and relativistic equations such as the Dirac equation emerge as low-energy limits of quantum walks and quantum cellular automata, discrete models of particles hopping on grids.
- Determine how continuous symmetries such as rotation and Lorentz invariance arise from discrete quantum models, and evaluate multiparticle quantum walks as an alternative model of quantum computation.
More about the research
Two projects approach this from different directions. One makes error correction practical on the small, noisy machines that exist today. The other uses simple discrete quantum models to understand, and possibly simulate, the theories that describe fundamental particles.
Why it matters
Reliable error correction is a central obstacle to building useful large quantum computers. Schemes that work on today's small processors, along with real-time decoders, could let researchers run longer and more accurate quantum computations sooner. The quantum walk work offers a different route to deriving and simulating the field theories of particle physics, which are hard to solve exactly and hard to simulate on ordinary computers.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Milad Marvian
University of New Mexico, NM·Physics·Early-career
Develop mathematical models describing how errors propagate through quantum circuits, and use them to construct resource-efficient fault-tolerant computing subroutines.
Chun Jun Cao
Virginia Polytechnic Institute and State University, VA·Physics·Early-career
Develop fault-tolerant decoding and error-correction protocols for holographic codes, which are quantum error-correcting codes inspired by quantum gravity and built from tensor networks.
Sonia Lopez Alarcon
Rochester Institute of Technology, NY·Computer Science
Train machine learning models to identify and synthesize qubit routing algorithms tailored to a specific quantum device and objective, including selection of optimal parameters and optimization functions.
The school
University of Southern California: 47 labs on PI Pages, $1.3B a year on research, 882 research doctorates a year.
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