Vacuum Phenomenology  

Vacuum Energy > s.a. Conformal Field Theory; Lamb Shift; symmetry breaking and vacuum [false vacuum decay].
* And the cosmological constant: It has often been suggested that the origin of the cosmological constant may be the vacuum energy of quantum fields; In that case, it is susceptible to Casimir-like fluctuations induced by gravitational sources; Another suggestion is that the vacuum energy itself does not gravitate, and the cosmological constant arises from fluctuations; One such proposal is the vacuum energy sequestering idea; > s.a. cosmological constant.
@ General references: Puthoff PRA(89), comment Wesson PRA(91), reply Puthoff PRA(91), comment Santos PRA(91), reply Puthoff PRA(91) [electromagnetic, origin]; Roberts ht/00 [rev]; Fulling JPA(03)qp [and heat kernel coefficients]; Volovik IJMPD(06)gq [myths]; Bruhn PS(06) [energy cannot be extracted]; Holdom NJP(08) [in massless QCD]; Duplančić et al PRD(10) [vacuum energy density probability distribution]; Calloni et al PRD(14), a1409 [weighing the vacuum, Archimedes project]; Alexander & Mersini-Houghton a1705 [and the hierarchy of forces].
@ In cosmology: Turner in(96)ap/97; Beck & Mackey PhyA(07), Rafelski et al a0909-conf [as dark energy]; Maggiore PRD(11)-a1004 [and the cosmological expansion]; Mangano a1005 [primordial perturbation spectrum and dark-energy parameter]; Albareti PRD(14)-a1404 [as dark matter].
@ Special situations: Nesterenko & Pirozhenko CQG(11) [conical spaces].
@ Non-gravitating: Datta CQG(95); Padmanabhan IJMPD(06)gq.
@ And the cosmological constant: Sahni MPLA(99); Razmi & Abbassi qp/99 [different approach]; Rugh & Zinkernagel SHPMP(02)ht/00 [conceptual]; Genet et al qp/02-IAP [rev]; Ford gq/02-IAP; Volovik AdP(05)gq/04; Marsh a0711 [need to redefine vacuum]; Santos ASS(10)-a0812; Durt a1302/EPL [astronomical consequences]; Visser a1610 [zero-point stress-energy tensor and Lorentz invariance].
@ Vacuum energy sequestering: Kaloper et al PRL(16)-a1505 [manifestly local theory]; Kaloper & Padilla a1606 [and graviton loops]; Bufalo et al PRD(16)-a1606 [canonical formulation and path integral].

Vacuum Fluctuations > s.a. fluctuations; higher-order gravity; quantum-gravity phenomenology; stochastic quantum mechanics.
* Zero-point fluctuations: Those corresponding to the residual energy a field has in the vacuum state.
* Applications: They are used to explain stability of atoms, Zitterbewegung, the Lamb shift, the Casimir effect and force, shot noise, Vilenkin's universe from nothing, black-hole radiation; They have been proposed as an explanation for the cosmological constant.
@ General references: Reynaud et al CRAS(01)qp; Santos qp/02 [reality]; Brustein & Oaknin PRD(03)ht/02 [pseudoclassical description].
@ And photon detectors: Santos qp/02; Marshall & Santos a0707 [classical model].
@ And atoms: NS(87)jul, NS(90)jul28 [stability]; Stenger et al PRL(99) [in Bose-Einstein condensates].
@ And decoherence: Santos PLA(94); Ellis et al qp/97-conf; Kim et al PRL(06) [dissipation, proposed experiment]; > s.a. models of decoherence; particle effects [creation]; quantum field theory effects in curved spacetime [quantum radiation].
@ And gravity: Stefanski & Bedford AJP(94)jul; Jaekel & Reynaud RPP(97)qp; Modanese FPL(03)ht/00; Rueda et al gq/01; Caldwell ap/02 [and Casimir effect]; Jaekel et al NAR(02); Padmanabhan IJMPD(06); Onofrio IJMPA(10)-a1101 [and non-Newtonian microscopic gravity]; Carlip et al PRL(11)-a1103 [and small-scale structure]; Hollenstein et al PRD(12)-a1111 [in cosmology]; Burton a1203 [entropy maximization]; Arzano et al PRD-a1505 [in theories with deformed dispersion relations]; Calloni et al NIMA(15)-a1511 [Archimedes experiment]; > s.a. gravitating matter [electromagnetic radiation]; quantum equivalence principle; inertia.
@ In cosmology: Albareti et al IJMPD(14)-a1405-GRF [and large-scale structure formation]; Zerbini a1411-conf [as quantum spacetime probes].
@ Focusing: Ford & Svaiter PRA(00)qp, PRA(02)qp [with mirrors].
@ Related topics: NS(89)dec2 [self-regenerating theory]; Kazakov JPA(06) [from quantum matter in an external electric field]; Nation et al RMP(12)-a1103 [amplifying in a superconducting circuit]; Brown et al PRD(15)-a1409 [vacuum entanglement and half of an empty cavity]; news sci(15)oct, sd(15)oct [claimed observation]; De Lorenci & Ford a1609 [classical enhancement].
> Related topics: see casimir effect; correlations; decoherence; electrodynamics [stochastic electrodynamics]; quantum particles; variation of constants.

Other Concepts / Effects > s.a. cosmological constant; dispersion; phase transitions; quantum fields in curved spacetime; radiation [pressure].
$ Vacuum persistence amplitude: The quantity

Z[J]:= \(\langle\)0+ | 0\(\rangle\)J = \(\cal D\)φ exp{ i (S[φ] + J[φ])} .

* Sparking of the vacuum: A non-perturbative QED effect in atomic physics; An atom with binding energy for the lowest-lying electron orbit greater that 2mec2, in a supercritical electrostatic field, would find it convenient to create an e+e pair and emit the positron; Such superheavy nuclei (Z > 173) do not exist, but the effect should show up as a Z-dependent and not too narrow peak in the positron spectrum in heavy ion collisions.
@ General references: Weigert PLA(96) [squeezing and Casimir]; Pettorino & Vilkovisky AP(01) [vmax of sources]; Scandurra ht/01 [thermodynamics]; Kunhardt PhD(01)mp [massless particles and "infravacua"]; Feigel PRL(04) [motion from vacuum]; Smolyaninov PRL(11) + news pw(12)jan [the vacuum as a metamaterial at very high magnetic fields]; Fulling et al JPA(12)-a1205 [wedges, cones, cosmic Strings and J S Dowker's contributions]; Pozas-Kerstjens & Martín-Martínez.
@ Entanglement harvesting: Pozas-Kerstjens & Martín-Martínez PRD(15)-a1506 [and classical correlations to particle detectors]; Pozas-Kerstjens & Martín-Martínez PRD(16)-a1605 [with hydrogen-like atoms].
> Related topics: see brownian motion; entanglement in quantum field theory; Friction; photon phenomenology; polarization [birefringence].

Vacuum in Specific Field Theories > s.a. QCD.
* Quantum gravity: The natural candidate for ground state of the equation Gab= 8πG \(\langle\)Tab\(\rangle\), flat spacetime gab = ηab, is not stable [may be false!]; The ground state for quantum gravity may not be a Gaussian centered around Minkowski space; > s.a. spacetime foam.
@ QED: Marshall PRS(63); Milonni PS(88), 94; Hofmann et al OE(98)qp/97 [fluctuations]; Greiner & Schramm AJP(08)jun [RL]; Donaire PRA(11)-a1012 [complex medium]; Białynicki-Birula & Rudnicki PRD(11)-a1103 [in a uniform electric field]; Calloni et al a1511-conf [weighing the electromagnetic vacuum].
@ QED, stability: Azam ht/01 [and Landau pole]; Solomon Ap(06)ht/04; Azam EJTP-a0806.
@ Quantum gravity: Horowitz in(81); Penrose in(91); Padmanabhan & Choudhury MPLA(00)gq; Compère & Long JHEP(16)-a1601 [and the BMS supertranslation symmetry].
@ Other theories: DeGrand et al NPB(97) [SU(2)]; Paniak et al NPB(97) [2D gauge theory]; Greensite et al PRD(11)-a1102 [Yang-Mills vacuum wavefunctional]; Krug a1404-PhD [3D Yang-Mills theory].

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