592 research outputs found
Gravity in 2T-Physics
The field theoretic action for gravitational interactions in d+2 dimensions
is constructed in the formalism of 2T-physics. General Relativity in d
dimensions emerges as a shadow of this theory with one less time and one less
space dimensions. The gravitational constant turns out to be a shadow of a
dilaton field in d+2 dimensions that appears as a constant to observers stuck
in d dimensions. If elementary scalar fields play a role in the fundamental
theory (such as Higgs fields in the Standard Model coupled to gravity), then
their shadows in d dimensions must necessarily be conformal scalars. This has
the physical consequence that the gravitational constant changes at each phase
transition (inflation, grand unification, electro-weak, etc.), implying
interesting new scenarios in cosmological applications. The fundamental action
for pure gravity, which includes the spacetime metric, the dilaton and an
additional auxiliary scalar field all in d+2 dimensions with two times, has a
mix of gauge symmetries to produce appropriate constraints that remove all
ghosts or redundant degrees of freedom. The action produces on-shell classical
field equations of motion in d+2 dimensions, with enough constraints for the
theory to be in agreement with classical General Relativity in d dimensions.
Therefore this action describes the correct classical gravitational physics
directly in d+2 dimensions. Taken together with previous similar work on the
Standard Model of particles and forces, the present paper shows that 2T-physics
is a general consistent framework for a physical theory.Comment: 24 pages, revision includes minor corrections and additional
clarifying materia
Improved Off-Shell Scattering Amplitudes in String Field Theory and New Computational Methods
We report on new results in Witten's cubic string field theory for the
off-shell factor in the 4-tachyon amplitude that was not fully obtained
explicitly before. This is achieved by completing the derivation of the
Veneziano formula in the Moyal star formulation of Witten's string field theory
(MSFT). We also demonstrate detailed agreement of MSFT with a number of
on-shell and off-shell computations in other approaches to Witten's string
field theory. We extend the techniques of computation in MSFT, and show that
the j=0 representation of SL(2,R) generated by the Virasoro operators
is a key structure in practical computations for generating
numbers. We provide more insight into the Moyal structure that simplifies
string field theory, and develop techniques that could be applied more
generally, including nonperturbative processes.Comment: 40 pages, 2 figures, LaTe
Dualities among 1T-Field Theories with Spin, Emerging from a Unifying 2T-Field Theory
The relation between two time physics (2T-physics) and the ordinary one time
formulation of physics (1T-physics) is similar to the relation between a
3-dimensional object moving in a room and its multiple shadows moving on walls
when projected from different perspectives. The multiple shadows as seen by
observers stuck on the wall are analogous to the effects of the 2T-universe as
experienced in ordinary 1T spacetime. In this paper we develop some of the
quantitative aspects of this 2T to 1T relationship in the context of field
theory. We discuss 2T field theory in d+2 dimensions and its shadows in the
form of 1T field theories when the theory contains Klein-Gordon, Dirac and
Yang-Mills fields, such as the Standard Model of particles and forces. We show
that the shadow 1T field theories must have hidden relations among themselves.
These relations take the form of dualities and hidden spacetime symmetries. A
subset of the shadows are 1T field theories in different gravitational
backgrounds (different space-times) such as the flat Minkowski spacetime, the
Robertson-Walker expanding universe, AdS(d-k) x S(k) and others, including
singular ones. We explicitly construct the duality transformations among this
conformally flat subset, and build the generators of their hidden SO(d,2)
symmetry. The existence of such hidden relations among 1T field theories, which
can be tested by both theory and experiment in 1T-physics, is part of the
evidence for the underlying d+2 dimensional spacetime and the unifying
2T-physics structure.Comment: 33 pages, LaTe
Interacting Two-Time Physics Field Theory With a BRST Gauge Invariant Action
We construct a field theoretic version of 2T-physics including interactions
in an action formalism. The approach is a BRST formulation based on the
underlying Sp(2,R)gauge symmetry, and shares some similarities with the
approach used to construct string field theory. In our first case of spinless
particles, the interaction is uniquely determined by the BRST gauge symmetry,
and it is different than the Chern-Simons type theory used in open string field
theory. After constructing a BRST gauge invariant action for 2T-physics field
theory with interactions in d+2 dimensions, we study its relation to standard
1T-physics field theory in (d-1)+1 dimensions by choosing gauges. In one gauge
we show that we obtain the Klein-Gordon field theory in (d-1)+1 dimensions with
unique SO(d,2) conformal invariant self interactions at the classical field
level. This SO(d,2) is the natural linear Lorentz symmetry of the 2T field
theory in d+2 dimensions. As indicated in Fig.1, in other gauges we expect to
derive a variety of SO(d,2)invariant 1T-physics field theories as gauge fixed
forms of the same 2T field theory, thus obtaining a unification of 1T-dynamics
in a field theoretic setting, including interactions. The BRST gauge
transformation should play the role of duality transformations among the
1T-physics holographic images of the same parent 2T field theory. The
availability of a field theory action opens the way for studying 2T-physics
with interactions at the quantum level through the path integral approach.Comment: 22 pages, 1 figure, v3 includes corrections of typos and some
comment
Hidden Symmetries, AdS_D x S^n, and the lifting of one-time-physics to two-time-physics
The massive non-relativistic free particle in d-1 space dimensions has an
action with a surprizing non-linearly realized SO(d,2) symmetry. This is the
simplest example of a host of diverse one-time-physics systems with hidden
SO(d,2) symmetric actions. By the addition of gauge degrees of freedom, they
can all be lifted to the same SO(d,2) covariant unified theory that includes an
extra spacelike and an extra timelike dimension. The resulting action in d+2
dimensions has manifest SO(d,2) Lorentz symmetry and a gauge symmetry Sp(2,R)
and it defines two-time-physics. Conversely, the two-time action can be gauge
fixed to diverse one-time physical systems. In this paper three new gauge fixed
forms that correspond to the non-relativistic particle, the massive
relativistic particle, and the particle in AdS_(d-n) x S^n spacetime will be
discussed. The last case is discussed at the first quantized and field theory
levels as well. For the last case the popularly known symmetry is SO(d-n-1,2) x
SO(n+1), but yet we show that it is symmetric under the larger SO(d,2). In the
field theory version the action is symmetric under the full SO(d,2) provided it
is improved with a quantized mass term that arises as an anomaly from operator
ordering ambiguities. The anomalous cosmological term vanishes for AdS_2 x S^0
and AdS_n x S^n (i.e. d=2n). The strikingly larger symmetry could be
significant in the context of the proposed AdS/CFT duality.Comment: Latex, 23 pages. The term "cosmological constant" that appeared in
the original version has been changed to "mass term". My apologies for the
confusio
Supersymmetric Field Theory in 2T-physics
We construct N=1 supersymmetry in 4+2 dimensions compatible with the
theoretical framework of 2T physics field theory and its gauge symmetries. The
fields are arranged into 4+2 dimensional chiral and vector supermultiplets, and
their interactions are uniquely fixed by SUSY and 2T-physics gauge symmetries.
Many 3+1 spacetimes emerge from 4+2 by gauge fixing. Gauge degrees of freedom
are eliminated as one comes down from 4+2 to 3+1 dimensions without any
remnants of Kaluza-Klein modes. In a special gauge, the remaining physical
degrees of freedom, and their interactions, coincide with ordinary N=1
supersymmetric field theory in 3+1 dimensions. In this gauge, SUSY in 4+2 is
interpreted as superconformal symmetry SU(2,2|1) in 3+1 dimensions.
Furthermore, the underlying 4+2 structure imposes some interesting restrictions
on the emergent 3+1 SUSY field theory, which could be considered as part of the
predictions of 2T-physics. One of these is the absence of the troublesome
renormalizable CP violating F*F terms. This is good for curing the strong CP
violation problem of QCD. An additional feature is that the superpotential is
required to have no dimensionful parameters. To induce phase transitions, such
as SUSY or electro-weak symmetry breaking, a coupling to the dilaton is needed.
This suggests a common origin of phase transitions that is driven by the vacuum
value of the dilaton, and need to be understood in a cosmological scenario as
part of a unified theory that includes the coupling of supergravity to matter.
Another interesting aspect is the possibility to utilize the inherent 2T gauge
symmetry to explore dual versions of the N=1 theory in 3+1 dimensions. This is
expected to reveal non-perturbative aspects of ordinary 1T field theory.Comment: 54 pages, late
STRINGY EVIDENCE FOR D=11 STRUCTURE IN STRONGLY COUPLED TYPE II-A SUPERSTRING
Witten proposed that the low energy physics of strongly coupled D=10 type-IIA
superstring may be described by D=11 supergravity. To explore the stringy
aspects of the underlying theory we examine the stringy massive states. We
propose a systematic formula for identifying non-perturbative states in D=10
type-IIA superstring theory, such that, together with the elementary excited
string states, they form D=11 supersymmetric multiplets multiplets in SO(10)
representations. This provides hints for the construction of a weakly coupled
D=11 theory that is dual to the strongly coupled D=10 type IIA superstring.Comment: LaTeX, revtex, 2-column, 10 pages
Superstrings with new supersymmetry in (9,2) and (10,2) dimensions
We construct superstring theories that obey the new supersymmetry algebra
{Q_a , Q_b}=\gamma_{ab}^{mn} P_{1m} P_{2n}, in a Green-Schwarz formalism, with
kappa supersymmetry also of the new type. The superstring is in a system with a
superparticle so that their total momenta are respectively. The
system is covariant and critical in (10,2) dimensions if the particle is
massless and in (9,2) dimensions if the particle is massive. Both the
superstring and superparticle have coordinates with two timelike dimensions but
each behaves effectively as if they have a single timelike dimension. This is
due to gauge symmetries and associated constraints. We show how to generalize
the gauge principle to more intricate systems containing two parts, 1 and 2.
Each part contains interacting constituents, such as p-branes, and each part
behaves effectively as if they have one timelike coordinate, although the full
system has two timelike coordinates. The examples of two superparticles, and of
a superparticle and a superstring, discussed in more detail are a special cases
of such a generalized interacting system.Comment: LaTeX, revtex, 9 page
Twistor Superstring in 2T-Physics
By utilizing the gauge symmetries of Two-Time Physics (2T-physics), a
superstring with linearly realized global SU(2,2|4) supersymmetry in 4+2
dimensions (plus internal degrees of freedom) is constructed. It is shown that
the dynamics of the Witten-Berkovits twistor superstring in 3+1 dimensions
emerges as one of the many one time (1T) holographic pictures of the 4+2
dimensional string obtained via gauge fixing of the 2T gauge symmetries. In
2T-physics the twistor language can be transformed to usual spacetime language
and vice-versa, off shell, as different gauge fixings of the same 2T string
theory. Further holographic string pictures in 3+1 dimensions that are dual
theories can also be derived. The 2T superstring is further generalized in the
SU(4)=SO(6) sector of SU(2,2|4) by the addition of six bosonic dimensions, for
a total of 10+2 dimensions. Excitations of the extra bosons produce a SU(2,2|4)
current algebra spectrum that matches the classification of the high spin
currents of N=4, d=4 super Yang Mills theory which are conserved in the weak
coupling limit. This spectrum is interpreted as the extension of the SU(2,2|4
classification of the Kaluza-Klein towers of typeII-B supergravity compactified
on AdS{5}xS(5), into the full string theory, and is speculated to have a
covariant 10+2 origin in F-theory or S-theory. Further generalizations of the
superstring theory to 3+2, 5+2 and 6+2 dimensions, based on the supergroups
OSp(8|4), F(4), OSp(8*|4) respectively, and other cases, are also discussed.
The OSp(8|4) case in 6+2 dimensions can be gauge fixed to 5+1 dimensions to
provide a formulation of the special superconformal theory in six dimensions
either in terms of ordinary spacetime or in terms of twistors.Comment: 26 pages, LaTeX. In version 3, section 5, it is argued that the 6+2
2T-superstring with OSp(8*|4) supersymmetry provides a description of the
special d=6 superconformal theory based on the tensor supermultiplet (not d=6
SYM as mentioned in version 2
- …