184 research outputs found
Quantization of Neveu-Schwarz-Ramond Superstring Model in 10+2-dimensional Spacetime
We construct a Neveu-Schwarz-Ramond superstring model which is invariant
under supersymmetric U(1)_V * U(1)_A gauge transformations as well as the
super-general coordinate, the super local Lorentz and the super-Weyl
transformations on the string world-sheet. We quantize the superstring model by
covariant BRST formulation a la Batalin and Vilkovisky and noncovariant
light-cone gauge formulation. Upon the quantizations the model turns out to be
formulated consistently in 10+2-dimensional background spacetime involving two
time dimensions.Comment: 1+61 pages, no figures, LaTe
Non-critical string field theory for 2d quantum gravity coupled to (p,q)--conformal fields
We propose a non-critical string field theory for quantum gravity
coupled to (,) conformal fields. The Hamiltonian is described by the
generators of the algebra, and the Schwinger-Dyson equation is equivalent
to a vacuum condition imposed on the generators of algebra.Comment: LaTeX, 30 pages, 6 figure
The bosonic string and superstring models in 26+2 and 10+2 dimensional space--time, and the generalized Chern-Simons action
We have covariantized the Lagrangians of the U(1)_V * U(1)_A models, which
have U(1)_V * U(1)_A gauge symmetry in two dimensions, and studied their
symmetric structures. The special property of the U(1)_V * U(1)_A models is the
fact that all these models have an extra time coordinate in the target
space-time. The U(1)_V * U(1)_A models coupled to two-dimensional gravity are
string models in 26+2 dimensional target space-time for bosonic string and in
10+2 dimensional target space-time for superstring. Both string models have two
time coordinates. In order to construct the covariant Lagrangians of the U(1)_V
* U(1)_A models the generalized Chern-Simons term plays an important role. The
supersymmetric generalized Chern-Simons action is also proposed. The
Green-Schwarz type of U(1)_V * U(1)_A superstring model has another fermionic
local symmetry as well as \kappa-symmetry. The supersymmetry of target
space-time is different from the standard one.Comment: 27 pages, no figure
Scale-dependent Hausdorff dimensions in 2d gravity
By appropriate scaling of coupling constants a one-parameter family of
ensembles of two-dimensional geometries is obtained, which interpolates between
the ensembles of (generalized) causal dynamical triangulations and ordinary
dynamical triangulations. We study the fractal properties of the associated
continuum geometries and identify both global and local Hausdorff dimensions.Comment: 12 pages, 3 figure
A modified Friedmann equation
We recently formulated a model of the universe based on an underlying
W3-symmetry. It allows the creation of the universe from nothing and the
creation of baby universes and wormholes for spacetimes of dimension 2, 3, 4, 6
and 10. Here we show that the classical large time and large space limit of
these universes is one of exponential fast expansion without the need of a
cosmological constant. Under a number of simplifying assumptions our model
predicts that w=-1.2 in the case of four-dimensional spacetime. The possibility
of obtaining a w-value less than -1 is linked to the ability of our model to
create baby universes and wormholes.Comment: Clarifying comment on page
Creating 3, 4, 6 and 10-dimensional spacetime from W3 symmetry
We describe a model where breaking of W3 symmetry will lead to the emergence
of time and subsequently of space. Surprisingly the simplest such models which
lead to higher dimensional spacetimes are based on the four "magical" Jordan
algebras of 3x3 Hermitian matrices with real, complex, quaternion and octonion
entries, respectively. The simplest symmetry breaking leads to universes with
spacetime dimensions 3, 4, 6, and 10
CDT and the Big Bang
We describe a CDT-like model where breaking of W3 symmetry will lead to the
emergence of time and subsequently of space. Surprisingly the simplest such
models which lead to higher dimensional spacetimes are based on the four
"magical" Jordan algebras of 3x3 Hermitian matrices with real, complex,
quaternion and octonion entries, respectively. The simplest symmetry breaking
leads to universes with spacetime dimensions 3, 4, 6, and 10
A model for emergence of space and time
We study string field theory (third quantization) of the two-dimensional
model of quantum geometry called generalized CDT ("causal dynamical
triangulations"). Like in standard non-critical string theory the so-called
string field Hamiltonian of generalized CDT can be associated with W-algebra
generators through the string mode expansion. This allows us to define an
"absolute" vacuum. "Physical" vacua appear as coherent states created by vertex
operators acting on the absolute vacuum. Each coherent state corresponds to
specific values of the coupling constants of generalized CDT. The cosmological
"time" only exists relatively to a given "physical" vacuum and comes into
existence before space, which is created because the "physical" vacuum is
unstable. Thus each CDT "universe" is created as a "Big Bang" from the absolute
vacuum, its time evolution is governed by the CDT string field Hamiltonian with
given coupling constants, and one can imagine interactions between CDT
universes with different coupling constants ("fourth quantization"
The causality road from dynamical triangulations to quantum gravity that describes our Universe
It is shown how one, guided by causality, starting from so-called dynamical
triangulations, is led to a candidate of quantum gravity that describes our
Universe. This theory is based on W- and Jordan algebras. It explains how our
Universe was created, how cosmic inflation began and ended, how the topology
and the geometry of our Universe was formed, and what was the origin of Big
Bang energy. The theory also leads to a modified Friedmann equation which
explains the present accelerating expansion of our Universe without appealing
to the cosmological constant.Comment: This is a contribution to the Handbook of Quantum Gravity which will
be published in 2023. It will appear as a chapter in the section of the
handbook denoted "Causal Dynamical Triangulations'
- …