Benchmarking exchange-only control of a 48-spin singlet manifold
Abstract
Exchange-only quantum computing benefits from high fidelity and straightforward control afforded by the exchange interaction. However, independently controllable qubits must be encoded into subsystems of at least three electron spins, restricting computation to only a fraction of the available spin Hilbert space. The remaining states are treated as leakage and used only transiently in gate sequences. By contrast, a quantitative, system-wide measure of exchange-only performance can exploit the full available Hilbert space, including states conventionally treated as leakage. Here, we apply this approach to arrays of up to 48 electron spins, accessing a total-spin-zero Hilbert space with dimension exceeding 240. Measurements of out-of-time-order correlators (OTOCs) reveal rich scrambling dynamics and demonstrate access to regimes relevant to quantum computational advantage. Using generalized forms of cross-entropy and mirror randomized benchmarking, we also assess the aggregate performance of the full exchange-only system per fundamental two-body interaction: the two-spin exchange. We obtain an effective system-level error of 3 × 10−4 per exchange, incorporating the complete experimental control sequence and all associated noise sources. This value is up to an order of magnitude lower than those reported from comparable benchmarks on other platforms at the time of writing.
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BibTeX
@misc{team2026benchmarking,
title = {{Benchmarking exchange-only control of a 48-spin singlet manifold}},
author = {HRL Quantum Team and Microsoft Collaborators and Stephen Carr and Matt Abbitt and Michael Abraham and Edwin Acuna and I. Alverado and Carter Andrews and Hussein Anton and Katherine M. Beech and Aaron J. Bluestone and Jacob Z. Blumoff and Matthew G. Borselli and Brydon Boyd and Jacob T. Boyer and Peter Brewer and Steven L. Brown and Joseph D. Broz and Tyler A. Cain and John B. Carpenter and Faustin W. Carter and Brittany Carter and Matthew D. Chambers and James M. Chappell and Kevin C. Chen and Edward H. Chen and Maxwell D. Choi and Matthew N. H. Chow and Justin E. Christensen and Aaron M. Chronister and Andrew M. Clapper and Michael D. Cornelius and Gregory M. Crosswhite and Stanislav Culaclii and Erik S. Daniel and Dominic Daprano and John K. David and Charles R. Elliott and Kevin Eng and Colin P. Feeney and David J. Fialkow and Dylan H. Finestone and Bryan H. Fong and Richie Fu and Zachary A. Geiger and Bradley W. Greene and Rafael Guerra-Fuentes and Hrayr K. Gurgenian and Alex Hamill and Brooke M. Hardesty and Jim W. Harrington and Alex Hirman and Donald A. Hitko and Silas Hoffman and Dominic Holloman and Daniel R. Hulbert and Jake Hundley and Clayton A. C. Jackson and Paul C. Jerger and B. Johnson},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.07393},
eprint = {2610.07393},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.07393},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Benchmarking exchange-only control of a 48-spin singlet manifold
AU - HRL Quantum Team
AU - Microsoft Collaborators
AU - Stephen Carr
AU - Matt Abbitt
AU - Michael Abraham
AU - Edwin Acuna
AU - I. Alverado
AU - Carter Andrews
AU - Hussein Anton
AU - Katherine M. Beech
AU - Aaron J. Bluestone
AU - Jacob Z. Blumoff
AU - Matthew G. Borselli
AU - Brydon Boyd
AU - Jacob T. Boyer
AU - Peter Brewer
AU - Steven L. Brown
AU - Joseph D. Broz
AU - Tyler A. Cain
AU - John B. Carpenter
AU - Faustin W. Carter
AU - Brittany Carter
AU - Matthew D. Chambers
AU - James M. Chappell
AU - Kevin C. Chen
AU - Edward H. Chen
AU - Maxwell D. Choi
AU - Matthew N. H. Chow
AU - Justin E. Christensen
AU - Aaron M. Chronister
AU - Andrew M. Clapper
AU - Michael D. Cornelius
AU - Gregory M. Crosswhite
AU - Stanislav Culaclii
AU - Erik S. Daniel
AU - Dominic Daprano
AU - John K. David
AU - Charles R. Elliott
AU - Kevin Eng
AU - Colin P. Feeney
AU - David J. Fialkow
AU - Dylan H. Finestone
AU - Bryan H. Fong
AU - Richie Fu
AU - Zachary A. Geiger
AU - Bradley W. Greene
AU - Rafael Guerra-Fuentes
AU - Hrayr K. Gurgenian
AU - Alex Hamill
AU - Brooke M. Hardesty
AU - Jim W. Harrington
AU - Alex Hirman
AU - Donald A. Hitko
AU - Silas Hoffman
AU - Dominic Holloman
AU - Daniel R. Hulbert
AU - Jake Hundley
AU - Clayton A. C. Jackson
AU - Paul C. Jerger
AU - B. Johnson
PY - 2026
DA - 2026/10/05
PB - arXiv
DO - 10.48550/arxiv.2610.07393
UR - https://arxiv.org/abs/2610.07393
AB - Exchange-only quantum computing benefits from high fidelity and straightforward control afforded by the exchange interaction. However, independently controllable qubits must be encoded into subsystems of at least three electron spins, restricting computation to only a fraction of the available spin Hilbert space. The remaining states are treated as leakage and used only transiently in gate sequences. By contrast, a quantitative, system-wide measure of exchange-only performance can exploit the full available Hilbert space, including states conventionally treated as leakage. Here, we apply this approach to arrays of up to 48 electron spins, accessing a total-spin-zero Hilbert space with dimension exceeding 2^40. Measurements of out-of-time-order correlators (OTOCs) reveal rich scrambling dynamics and demonstrate access to regimes relevant to quantum computational advantage. Using generalized forms of cross-entropy and mirror randomized benchmarking, we also assess the aggregate performance of the full exchange-only system per fundamental two-body interaction: the two-spin exchange. We obtain an effective system-level error of 3 × 10^−4 per exchange, incorporating the complete experimental control sequence and all associated noise sources. This value is up to an order of magnitude lower than those reported from comparable benchmarks on other platforms at the time of writing.
ER -