Historical research guide · 1082 · 2008
The localized quantum vacuum field
Daniela Dragoman
In one minute
Daniela Dragoman of the University of Bucharest proposes that the vacuum is not everywhere. In standard quantum field theory every mode of the electromagnetic field carries half a quantum of energy whether or not a photon is in it, and summing over all modes fills the whole universe — which is why the predicted vacuum energy overshoots the measured cosmological constant by at least forty orders of magnitude. Dragoman keeps the effects and moves the source. In her model a charged particle sitting in its ground state does what an excited one does: it emits a real photon and drops into a negative-energy state, that state is unstable, it absorbs the photon straight back, and the cycle begins again. The photon lives only as long as the uncertainty principle allows, so the field it makes reaches only about a reduced wavelength outward — a vacuum that clings to matter. The Casimir force and the Lamb shift survive intact, and the cut-off frequency every Casimir derivation needs becomes the material's own highest oscillation frequency.
Connection
Chapter 2 is about what the vacuum actually is, and this is one of the sharpest attempts to keep everything the laboratory has measured about it while dropping the one number nobody can defend. It matters for the site's own accounting: if the zero-point field is generated by matter and localised around it, then the enormous energy densities quoted for free space are a statement about what sits near matter, and a device that reaches for that energy has to be built next to something.
From the source
The zero-point energy of the quantum electromagnetic field originates in energy- and momentum-conserving transitions of material systems from their ground state to an unstable state with negative energy, accompanied by emission and re-absorption of real — not virtual — photons.Abstract; section 'The Localized Quantum Vacuum', paragraphs 3 to 5
A negative-energy state of a harmonic oscillator of mass m is formally the state of an oscillator of mass minus m, and the two quantum states are identical; the negative mass here is dynamic in character, with no negative gravitational mass and no negative inertial mass involved, because in that state the particle is entangled with the photon and no force applies to the particle alone.Equations 3 and 4, and the two paragraphs following them
Because the emitted photon exists only for the uncertainty-limited interval, the electromagnetic field state extends around the material particle over a distance of roughly the reduced wavelength of the emitted radiation — so the universe is not bathed in zero-point energy, we sense it only because it is present around every material particle, and vacuum effects are primarily low-frequency, non-relativistic effects.Section 'The Localized Quantum Vacuum', the paragraph beginning 'The unstable quantum particle exists in the state with negative energy'
The expression for the Casimir force between parallel conducting plates is unchanged by this model: every derivation introduces an arbitrary frequency cut-off and quantises the field between the plates, and both survive — with the added insight that the cut-off is the highest oscillation frequency of the material system, which is finite for any particle, so the vacuum energy density cannot diverge even next to matter.Section following equation 13, the paragraph beginning 'How does the present interpretation of the origin of ZPE change the predictions of standard quantum theory?'
The cosmological paradox dissolves, because the zero-point energy does not exist far from matter and so does not overflow the universe — while cosmological effects related to quantum fields, such as vacuum lensing near magnetised neutron stars, still follow naturally since those stars are themselves material systems.Introduction, paragraph 4; the same paragraph following equation 13; Discussions and Conclusions
The model makes two testable predictions that separate it from standard quantum field theory: the Zitterbewegung recoils should be pairwise correlated, the recoil at emission and at re-absorption of the same photon being identical; and vacuum birefringence in strong fields — not yet observed — should be impossible to see far from material systems.Discussions and Conclusions, final paragraph; the paragraph on vacuum birefringence
The way in
https://doi.org/10.1088/0031-8949/77/03/035005How to cite it
Daniela Dragoman (2008) The localized quantum vacuum field doi:10.1088/0031-8949/77/03/035005