22 research outputs found
On The Symplectic Two-Form of Gravity in Terms of Dirac Eigenvalues
The Dirac eigenvalues form a subset of observables of the Euclidean gravity.
The symplectic two-form in the covariant phase space could be expressed, in
principle, in terms of the Dirac eigenvalues. We discuss the existence of the
formal solution of the equations defining the components of the symplectic form
in this framework.Comment: misprints corrected, final interpretation of results give
Duality between coordinates and Dirac field
The duality between the Cartesian coordinates on the Minkowski space-time and
the Dirac field is investigated. Two distinct possibilities to define this
duality are shown to exist. In both cases, the equations satisfied by
prepotentials are of second order.Comment: 4 pages, REVTeX, two typos in references were corrected, to be
published in Phys. Lett.
Duality of Coordinates and Matter Fields in Curved Spacetime
We show that there exists a duality between the local coordinates and the
solutions of the Klein-Gordon equation in curved spacetime in the same sense as
in the Minkowski spacetime. However, the duality in curved spacetime does not
have the same generality as in flat spacetime and it holds only if the system
satisfies certain constraints. We derive these constraints and the basic
equations of duality and discuss the implications in the quantum theory.Comment: 14 pages, ReVTeX file. Comments added, to appear in Phys.Lett.
Bosonic D-Branes at Finite Temperature
We derive the finite temperature description of bosonic D-branes in the
thermo field approach. The results might be relevant to the study of thermical
properties of D-brane systems.Comment: 12 pages, REVTeX. one reference added, to be published in Phys. Lett.
On the Dirac Eigenvalues as Observables of the on-shell N=2 D=4 Euclidean Supergravity
We generalize previous works on the Dirac eigenvalues as dynamical variables
of the Euclidean gravity and N=1 D=4 supergravity to on-shell N=2 D=4 Euclidean
supergravity. The covariant phase space of the theory is defined as as the
space of the solutions of the equations of motion modulo the on-shell gauge
transformations. In this space we define the Poisson brackets and compute their
value for the Dirac eigenvalues.Comment: 10 pages, LATeX fil
Time varying gravitational constant G via the entropic force
If the uncertainty principle applies to the Verlinde entropic idea, it leads
to a new term in the Newton's second law of mechanics in the Planck's scale.
This curious velocity dependence term inspires a frictional feature of the
gravity. In this short letter we address that this new term modifies the
effective mass and the Newtonian constant as the time dependence quantities.
Thus we must have a running on the value of the effective mass on the particle
mass near the holographic screen and the . This result has a nigh
relation with the Dirac hypothesis about the large numbers hypothesis (L.N.H.)
[1]. We propose that the corrected entropic terms via Verlinde idea can be
brought as a holographic evidence for the authenticity of the Dirac idea.Comment: Accepted for publication in "Communications in Theoretical Physics
(CTP)",Major revisio
First Order Semiclassical Thermal String in the AdS Spacetime
We formulate the finite temperature theory for the free thermal excitations
of the bosonic string in the anti-de Sitter (AdS) spacetime in the Thermo Field
Dynamics (TFD) approach. The spacetime metric is treated exactly while the
string and the thermal reservoir are semiclassically quantized at the first
order perturbation theory with respect to the dimensionless parameter \epsilon
= \a ' H^{-2}. In the conformal black-hole AdS background the
quantization is exact. The method can be extended to the arbitrary AdS
spacetime only in the first order perturbation. This approximation is taken in
the center of mass reference frame and it is justified by the fact that at the
first order the string dynamics is determined only by the interaction between
the {\em free} string oscillation modes and the {\em exact} background. The
first order thermal string is obtained by thermalization of the system
carried on by the TFD Bogoliubov operator. We determine the free thermal string
states and compute the local entropy and free energy in the center of mass
reference frame.Comment: Minor typos corrected. Two references added. LATeX file, 19 page
Nonequilibrium dynamics of strings in time-dependent plane wave backgrounds
We formulate and study the nonequilibrium dynamics of strings near the
singularity of the time-dependent plane wave background in the framework of the
Nonequilibrium Thermo Field Dynamics (NETFD). In particular, we construct the
Hilbert space of the thermal string oscillators at nonequilibrium and
generalize the NETFD to describe the coordinates of the center of mass of the
thermal string. The equations of motion of the thermal fields and the
Hamiltonian are derived. Due to the time-dependence of the oscillator
frequencies, a counterterm is present in the Hamiltonian. This counterterm
determines the correlation functions in a perturbative fashion. We compute the
two point correlation function of the thermal string at zero order in the power
expansion.Comment: 21 page
On the Origin of Entropic Gravity and Inertia
It was recently suggested that quantum field theory is not fundamental but
emerges from the loss of phase space information about matter crossing causal
horizons. Possible connections between this formalism and Verlinde's entropic
gravity and Jacobson's thermodynamic gravity are proposed.
The holographic screen in Verlinde's formalism can be identified as local
Rindler horizons and its entropy as that of the bulk fields beyond the
horizons.
This naturally resolves some issues on entropic gravity.
The quantum fluctuation of the fields is the origin of the thermodynamic
nature of entropic gravity.
It is also suggested that inertia is related to dragging
Rindler horizons.Comment: 9 pages, revtex4-1, 3 figures, accepted for publication in
Foundations of Physic
Higher Dimensional Recombination of Intersecting D-branes
We study recombinations of D-brane systems intersecting at more than one
angle using super Yang-Mills theory. We find the condensation of an
off-diagonal tachyon mode relates to the recombination, as was clarified for
branes at one angle in hep-th/0303204. For branes at two angles, after the
tachyon mode between two D2-branes condensed, D2-brane charge is distributed in
the bulk near the intersection point. We also find that, when two intersection
angles are equal, the off-diagonal lowest mode is massless, and a new stable
non-abelian configuration, which is supersymmetric up to a quadratic order in
the fluctuations, is obtained by the deformation by this mode.Comment: 18 pages, 2 figures, JHEP style. v3:references added, minor
corrections, English improve