4,874 research outputs found
Local -functions, stress-energy tensor, field fluctuations, and all that, in curved static spacetime
This is a quick review on some technology concerning the local zeta function
applied to Quantum Field Theory in curved static (thermal) spacetime to
regularize the stress-energy tensor and the field fluctuations.Comment: LaTeX 10 Pages. Submitted to the volume "Cosmology, Quantum Vacuum,
and Zeta Functions", in honour of Professor Emilio Elizalde on the occasion
of his 60th birthda
Canonical Quantization of Photons in a Rindler Wedge
Photons and thermal photons are studied in the Rindler Wedge employing
Feynman's gauge and canonical quantization. A Gupta-Bleuler-like formalism is
explicitly implemented. Non thermal Wightman functions and related (Euclidean
and Lorentzian) Green functions are explicitly calculated and their complex
time analytic structure is analyzed using the Fulling-Ruijsenaars master
function. The invariance of the advanced minus retarded fundamental solution is
checked and a Ward identity discussed. It is suggested the KMS condition can be
implemented to define thermal states also dealing with unphysical photons.
Following this way, thermal Wightman functions and related (Euclidean and
Lorentzian) Green functions are built up. Their analytic structure is examined
employing a thermal master function as in the non thermal case and other
corresponding properties are discussed. Some subtleties arising dealing with
unphysical photons in presence of the Rindler conical singularity are pointed
out. In particular, a family of thermal Wightman and Schwinger functions with
the same physical content is proved to exist due to a remaining static gauge
ambiguity. A photon version of Bisognano-Wichmann theorem is investigated in
the case of photons propagating in the Rindler Wedge employing Wightman
functions. Despite of the found ambiguity in defining Rindler Green functions,
the coincidence of -Rindler Wightman functions and Minkowski
Wightman functions is proved dealing with test functions related to physical
photons and Lorentz photons.Comment: 32 pages, latex, no figures, revised version, no changes in the
physical results, to be published in J. Math. Phy
QFT holography near the horizon of Schwarzschild-like spacetimes
It is argued that free QFT can be defined on the event horizon of a
Schwarzschild-like spacetime and that this theory is unitarily and
algebraically equivalent to QFT in the bulk (near the horizon). Under that
unitary equivalence the bulk hidden SL(2,R) symmetry found in a previous work
becomes manifest on the event horizon, it being induced by a group of horizon
diffeomorphisms. The class of generators of that group can be enlarged to
include a full Virasoro algebra of fields which are defined on the event
horizon. These generators have a quantum representation in QFT on the event
horizon and thus in the bulk.Comment: 8 pages, 1 figure, latex 2e, Relevant references adde
Gravity from Dirac Eigenvalues
We study a formulation of euclidean general relativity in which the dynamical
variables are given by a sequence of real numbers , representing
the eigenvalues of the Dirac operator on the curved spacetime. These quantities
are diffeomorphism-invariant functions of the metric and they form an infinite
set of ``physical observables'' for general relativity. Recent work of Connes
and Chamseddine suggests that they can be taken as natural variables for an
invariant description of the dynamics of gravity. We compute the Poisson
brackets of the 's, and find that these can be expressed in terms
of the propagator of the linearized Einstein equations and the energy-momentum
of the eigenspinors. We show that the eigenspinors' energy-momentum is the
Jacobian matrix of the change of coordinates from the metric to the
's. We study a variant of the Connes-Chamseddine spectral action
which eliminates a disturbing large cosmological term. We analyze the
corresponding equations of motion and find that these are solved if the energy
momenta of the eigenspinors scale linearly with the mass. Surprisingly, this
scaling law codes Einstein's equations. Finally we study the coupling to a
physical fermion field.Comment: An enlarged and improved version which will be pubblished in Mod.
Phys. Lett.
- …