Quantum atmospherics for materials diagnosis
Qing-Dong Jiang · Frank Wilczek
Abstract and summary · read the original at the source · APS default licence; no Creative Commons statement
In one page
Qing-Dong Jiang and Frank Wilczek point out that a material does not stop at its surface. If the matter inside breaks a symmetry — if it treats left and right, or forward and backward in time, differently — the quantum fluctuations of the electromagnetic field just outside inherit that lopsidedness. They call the result a quantum atmosphere, and they propose using it as an instrument: park an atom or a nitrogen-vacancy centre a few nanometres above a sample and read the material’s hidden order off the shift in the atom’s spectral lines, without touching the sample. One case is worked out in full. The surface of a topological insulator carries the extra term of axion electrodynamics, a piece of theory Wilczek wrote in 1987 for fundamental physics and now realised in a solid, and the atmosphere above it pulls on an electron’s spin like a magnetic field of about ten gauss at ten nanometres — far above what diamond magnetometers detect. They give the same treatment to time-reversal-breaking superconductors, then classify every operator such an atmosphere can be built from.
Why it matters hereChapter 2 holds that the vacuum is a structured medium rather than an absence, and this is that structure being turned into an instrument — the material’s own broken symmetry printed into the empty space above it and read back through an atom’s spectrum. Chapter 5 gets the analogue case, a field theory written for fundamental physics turning up inside a solid, and chapter 11 gets a way to identify a superconductor that does not depend on the Meissner effect and so survives in small samples and in the presence of magnetism.
What it claims
01Symmetry-breaking states of matter transmit their broken symmetry, through quantum fluctuations, to atoms and molecular complexes sitting near them, perturbing those spectra — so the vacuum immediately outside a sample becomes a readable diagnostic of the order inside it, and the authors judge spectroscopy an easier route to these effects than the long-range Casimir-type forces they also produce.Abstract; Introduction, first and second paragraphs; Summary
Published and peer-reviewed02A topological insulator’s boundary carries the axion-electrodynamics term, the product of the electric and magnetic fields with a coefficient that is an odd integer times the fine-structure constant; because that product is a total derivative it changes nothing in the bulk, but at a boundary it leaves a Chern-Simons surface action and a two-photon vertex that violates parity and time reversal locally while preserving their product.Equations 1 and 2; Figure 1
Published and peer-reviewed03Evaluating the corresponding Feynman diagram gives a spin-dependent potential falling as the inverse square of the distance from the surface, which written as an equivalent Zeeman field is of order ten gauss at ten nanometres — many orders of magnitude above the sensitivity of nitrogen-vacancy-centre magnetometry — although it is not true magnetic flux, so a SQUID detector registers nothing.Equations 3, 4 and 5; the paragraph following Equation 4
Published and peer-reviewed04Applying an external electric field introduces no time-reversal violation of its own, but on such a surface it induces either a Hall-like current sheet or a surface magnetic charge, and either one produces a real magnetic field aligned or antialigned with the applied field of order ten gauss for a field of ten thousand volts per centimetre.Equation 6 and the paragraph introducing it
Published and peer-reviewed05Chiral superconductors break time-reversal symmetry through the finite orbital angular momentum of their Cooper pairs, and their atmosphere produces a state-dependent magnetic energy shift that splits states of opposite angular momentum — mimicking a Zeeman interaction with an emergent magnetic field, and offering a discovery signature that does not rely on the Meissner effect, which is poorly suited to small regions and is itself disrupted by magnetism.Section ‘Atmosphere of superconductors’; Equation 7
Published and peer-reviewed06Classifying every local electromagnetic operator that is quadratic in the fields and lowest order in gradients by its parity and time-reversal character yields eight candidates beyond the two Maxwell terms, and that inventory tells an experimenter what to look for: exclude a normal-times-spin interaction in a planar geometry first, then look for the two-direction operator in a more complex geometry, and watch for an atmospheric magnetic field whose direction depends on whether the applied electric field is rising or falling.Section ‘Operator analysis of polarizabilities’; Equations 9 to 14
What to watch
The way in
https://doi.org/10.1103/physrevb.99.201104Published as Physical Review B volume 99, article 201104(R), 2019 — a Rapid Communication received 19 September 2018 and published 10 May 2019, copyright 2019 the American Physical Society. The article carries the APS default licence and no Creative Commons statement, and the preprint arXiv:1809.01692 version 3 carries the arXiv non-exclusive distribution licence, which is not a Creative Commons licence either, so this sheet stays abstract-only. The abstract below is the published one, verbatim, with the article’s own typographic quotation marks kept. The summary and every claim were written from the complete published article, retrieved on 2026-09-08 from the APS full-text endpoint and read end to end; each locator points to a numbered equation, a figure or a named section of it. The Supplemental Material, which holds the detailed Chern-Simons and superconducting calculations, was not retrieved, and no claim here depends on it. Companion sheets: the same authors’ chiral Casimir forces at /library/stm-ff1970e424 and the cavity-enhanced superconductivity experiment at /library/stm-b7a1a66f71.
How to cite it
Qing-Dong Jiang, Frank Wilczek (2019) Quantum atmospherics for materials diagnosis. doi:10.1103/physrevb.99.201104
Where it sits in the curriculum
What the vacuum isThe vacuum as a quantum fluidGravity control and superconductors