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Metabolic quantum limit to the information capacity of magnetoencephalography

E. Gkoudinakis1,2, S. Li3, and I. K. Kominis1,2,*

  • *Contact author: ikominis@uoc.gr
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Phys. Rev. Research 8, 023267 – Published 9 June, 2026

DOI: https://doi.org/10.1103/kqxb-y7p9

Abstract

Magnetoencephalography (MEG) measures the magnetic fields generated by neural currents using quantum sensors such as superconducting quantum interference devices and atomic magnetometers. Here, we combine the energy resolution limit of magnetic sensing with the metabolic power available to neural currents to derive a technology-independent bound on the information capacity of MEG. The bound factorizes into geometry, metabolism, and Planck's constant, and gives an estimated maximum information rate of 2.2 Mbit/s for representative human-brain parameters. Further, we show that the externally measurable magnetic field has a finite angular bandwidth, with high multipole components being geometrically attenuated and falling below the quantum-limited noise floor. This yields an information-limited spatial scale of order 1cm and renders the accessible measurement space effectively finite dimensional. The energy resolution limit therefore defines an information-theoretic Nyquist scale for magnetoencephalography, beyond which denser spatial sampling provides redundant measurements rather than additional recoverable information. Since the energy resolution limit also makes the noise variance grow linearly with measurement bandwidth, temporal and spatial bandwidths compete, producing a fundamental spatiotemporal trade-off. These results show how quantum-limited measurements constrain the observable complexity and information content of noninvasive brain imaging, providing a quantitative link between fundamental physics and neuroscience.

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Phys. Rev. Research 8, 023267– Published 9 June, 2026
  • Received 7 November 2025
  • Revised 25 February 2026
  • Accepted 10 May 2026
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