C. Jess Riedel

C. Jess Riedel(Blog/Twitter)

Senior Research Scientist
Foundations and Theory Group leader
NTT Research - Physics & Informatics Lab

Field: Physics - Quantum information and foundations
Topics: Decoherence, wavefunction branches, quantum-enhanced soft-particle detection

Email: jessriedel[at]gmail.com
CV | Papers: arXiv/Google Scholar

I work on quantum decoherence, concentrating especially on two ideas:

Rigorous wavefunction branches

What are the branches in the wavefunction of many-body systems? A clear description of the quantum-classical transition requires a precise understanding of the imprint left by physical amplification processes on the wavefunction of macroscopic systems, with laboratory measurement as a special case. One way to formulate this is the set selection problem. In addition to clarifying foundational questions, this will have applications in numerical many-body simulations.
VIDEO: [5-minute intro] [45-minute talk]

CJR, "Classical branch structure from spatial redundancy in a many-body wavefunction", Phys. Rev. Lett. 118, 120402 (2017).

[arXiv:1608.05377][Slides (UT Austin)]

F. Hernández, D. Ranard, and CJR, "Decoherence ensures classicality beyond the Ehrenfest time as ħ → 0".


F. Hernández, D. Ranard, and CJR, "The ħ → 0 limit of open quantum systems with general Lindbladians: vanishing noise ensures classicality beyond the Ehrenfest time".


Elliot Nelson and CJR, "Classical Entanglement Structure in the Wavefunction of Inflationary Fluctuations", Int. J. Mod. Phys. D 26, 1743006 (2017). Selected for Honorable Mention in the Gravity Research Foundation essay competition.

[arXiv:1704.00728][Slides (York)]

Elliot Nelson and CJR, "Classical Branches and Entanglement Structure in the Wavefunction of Cosmological Fluctuations".

[arXiv:1711.05719][Slides (Nelson, Caltech)]

CJR, Wojciech H. Zurek, and Michael Zwolak, "The Objective Past of a Quantum Universe: Redundant Records of Consistent Histories", Phys. Rev. A, 93, 032126 (2016).

[arXiv:1312.0331][Slides (IBM)][Video (IBM)]

Decoherence detection

How can large quantum superpositions be used to detect decoherence from new particles and forces that are otherwise undetectable? Early work on this has concentrated on the sensitivity of matter interferometers to detect low-mass (keV-MeV) dark matter, but the mechanism is very general and potentially can be exploited in other experiments and for other searches.

CJR and Itay Yavin, "Decoherence as a way to measure extremely soft collisions with Dark Matter", Phys. Rev. D 96, 023007 (2017).

[arXiv:1609.04145][Video (Perimeter)][Slides (LBNL)]

CJR, "Decoherence from classically undetectable sources: Standard quantum limit for diffusion". Phys. Rev. A 92, 010101(R) (2015).

[arXiv:1504.03250][Slides (Les Houches)]

Daniel Carney et al., "Mechanical Quantum Sensing in the Search for Dark Matter". Quantum Sci. Technol., 6, 024002 (2021).


R. Kaltenbaek et al., "MAQRO -- BPS 2023 Research Campaign Whitepaper".


CJR, "Direct Detection of Classically Undetectable Dark Matter through Quantum Decoherence", Phys. Rev. D 88, 116005 (2013).

[arXiv:1212.3061][Slides (Perimeter)][Video (Perimeter)][FAQs (Blog)]

Some other papers

F. Hernández and CJR, "Rapidly Decaying Wigner Functions are Schwartz Functions," J. Math. Phys. 63, 022104 (2022).


J. Sevilla and CJR, "Forecasting timelines of quantum computing".


C. H. Bennett, R. Hanson, and CJR, "Comment on 'The aestivation hypothesis for resolving Fermi's paradox'," Found. Phys. 49, 820 (2019).


CJR and Wojciech H. Zurek, "Quantum Darwinism in an Everyday Environment: Huge Redundancy in Scattered Photons," Phys. Rev. Lett. 105, 020404 (2010).


Michael Zwolak, CJR, and Wojciech H. Zurek, "Amplification, Redundancy, and the Quantum Chernoff Information", Phys. Rev. Lett. 112, 140406 (2014).

[arXiv:1312.5373][Video (Zwolak, IBM)]

CJR, "Quantum Brownian motion as an iterated entanglement-breaking measurement by the environment", Phys. Rev. A 93, 012107 (2016)

[arXiv:1507.04083][Slides (Los Alamos)]

CJR, Wojciech H. Zurek, and Michael Zwolak, "The Rise and Fall of Redundancy in Decoherence and Quantum Darwinism," New J. Phys. 14, 083010 (2012).

[arXiv:1205.3197][Slides (thesis defense)]

CJR, "Evidence for Gravitons from Decoherence by Bremsstrahlung".


(Collaborators: Charles H. Bennett, Robin Hanson, Felipe Hernández, Elliot Nelson, Daniel Ranard, Joshua Rosaler, Jaime Sevilla, Itay Yavin, Michael Zwolak, Wojciech H. Zurek.)

Online Persona

HackerNews, StackExchange (Physics.SE, MathOverflow), EA Forum / Hub, foreXiv (blog), Google Scholar, arXiv, Twitter.

Former institutions

Perimeter Institute (2014-2019)
IBM Watson Research Center, Yorktown Heights, (2012-2014)
Los Alamos National Lab: CNLS & T-4 (2009-2012)
UC Santa Barbara Physics (2007-2012)
Princeton Physics (2003-2007)
Thomas Jefferson HSST (1999-2003)

Mailing address

Jess Riedel
NTT Research, Inc.
940 Stewart Dr.
Sunnyvale, CA 94085

Personal pages

AGI and Value Lock-in, with Lukas Finnveden and Carl Shulman.
(Old value lock-in notes: PDF / Google Doc.)
TAI Safety Bibliographic Database
Software I use and recommend
Public bets