2,032 research outputs found
E_11 and M Theory
We argue that eleven dimensional supergravity can be described by a
non-linear realisation based on the group E_{11}. This requires a formulation
of eleven dimensional supergravity in which the gravitational degrees of
freedom are described by two fields which are related by duality. We show the
existence of such a description of gravity.Comment: 21 pages, some typos corrected and two references adde
Perceived Addictiveness of Marijuana, Tobacco and Alcohol Use in Vermont Youth and Young Adults: Associations Between Addiction Perceptions, Sociodemographics, and Substance Use
Dual and poly-tobacco and substance use are increasingly prevalent in youth and young adults. Current substance use prevention media efforts target addiction perceptions in young people; however, little is known about the perceived addictiveness of multiple substances among young people. The goal of the current study is to examine youth and young adults perceive addictiveness across several substances and the associations between addiction perceptions and substance use. Data were collected in Spring and Summer 2019 (Waves 1 and 2) as part of PACE Vermont, an online cohort study of Vermonters aged 12–25. Latent class analyses grouped participants by responses to an item that assessed perceived addictiveness of nicotine, caffeine, alcohol, marijuana, cigarettes, electronic vapor products, and opioids. Bivariate and multivariable multinomial logistic regression estimated relative risk ratios (RRR) for correlations between latent classes and sociodemographics and substance use among Vermont youth and young adults. Four emergent latent classes were defined as: 1) high perceived addictiveness (n=346; 30%), 2) low perceived addictiveness of marijuana (n=684; 59%), 3) mixed addiction perceptions (n=93; 8%), and 4) low perceived addictiveness (n=45; 4%). Latent class membership was associated with sociodemographics and current and ever substance use. For each year increase in age, there was a 44% increased likelihood of being in Class 2 compared to Class 1. Similarly, each year increase in age corresponded with a 42% increased likelihood of belonging to Class 3 compared to Class 1. Findings from this study provide novel evidence that youth and young adult beliefs about addictiveness across substances are correlated with substance use behaviors and demographic factors, including age. The strong association between age and class membership defined by low and mixed addiction perceptions suggests differences in addiction perceptions in youth compared to young adults. These associations signal novel opportunities to target addiction perceptions in messaging to young adults as well as youth to prevent substance use
The E_{11} origin of all maximal supergravities
Starting from the eleven dimensional E_{11} non-linear realisation of
M-theory we compute all possible forms, that is objects with totally
antisymmetrised indices, that occur in four dimensions and above as well as all
the 1-forms and 2-forms in three dimensions. In any dimension D, the D-1-forms
lead to maximal supergravity theories with cosmological constants and they are
in precise agreement with the patterns of gauging found in any dimension using
supersymmetry. The D-forms correspond to the presence of space-filling branes
which are crucial for the consistency of orientifold models and have not been
derived from an alternative approach, with the exception of the 10-dimensional
case. It follows that the gaugings of supergravities and the spacetime-filling
branes possess an eleven dimensional origin within the E_{11} formulation of
M-theory. This and previous results very strongly suggest that all the fields
in the adjoint representation of E_{11} have a physical interpretation.Comment: 54 page
G+++ Invariant Formulation of Gravity and M-Theories: Exact BPS Solutions
We present a tentative formulation of theories of gravity with suitable
matter content, including in particular pure gravity in D dimensions, the
bosonic effective actions of M-theory and of the bosonic string, in terms of
actions invariant under very-extended Kac-Moody algebras G+++. We conjecture
that they host additional degrees of freedom not contained in the conventional
theories. The actions are constructed in a recursive way from a level expansion
for all very-extended algebras G+++. They constitute non-linear realisations on
cosets, a priori unrelated to space-time, obtained from a modified Chevalley
involution. Exact solutions are found for all G+++. They describe the algebraic
properties of BPS extremal branes, Kaluza-Klein waves and Kaluza-Klein
monopoles. They illustrate the generalisation to all G+++ invariant theories of
the well-known duality properties of string theories by expressing duality as
Weyl invariance in G+++. Space-time is expected to be generated dynamically. In
the level decomposition of E8+++ = E11, one may indeed select an A10
representation of generators Pa which appears to engender space-time
translations by inducing infinite towers of fields interpretable as field
derivatives in space and time.Comment: Latex 45 pages, 1 figure. Discussion on pages 19 and 20 altered.
Appendix B amplified. 4 footnotes added. 2 references added. Acknowledgments
updated. Additional minor correction
Time-like T-duality algebra
When compactifying M- or type II string-theories on tori of indefinite
space-time signature, their low energy theories involve sigma models on
E_{n(n)}/H_n, where H_n is a not necessarily compact subgroup of E_{n(n)} whose
complexification is identical to the complexification of the maximal compact
subgroup of E_{n(n)}. We discuss how to compute the group H_n. For finite
dimensional E_{n(n)}, a formula derived from the theory of real forms of E_n
algebra's gives the possible groups immediately. A few groups that have not
appeared in the literature are found. For n=9,10,11 we compute and describe the
relevant real forms of E_n and H_n. A given H_n can correspond to multiple
signatures for the compact torus. We compute the groups H_n for all
compactifications of M-, M*-, and M'-theories, and type II-, II*- and
II'-theories on tori of arbitrary signature, and collect them in tables that
outline the dualities between them. In an appendix we list cosets G/H, with G
split and H a subgroup of G, that are relevant to timelike toroidal
compactifications and oxidation of theories with enhanced symmetries.Comment: LaTeX, 37 pages, 1 eps-figure, uses JHEP.cls; v2. corrected typo's in
tables 16 and 17, minor changes to tex
Duality Symmetries and G^{+++} Theories
We show that the non-linear realisations of all the very extended algebras
G^{+++}, except the B and C series which we do not consider, contain fields
corresponding to all possible duality symmetries of the on-shell degrees of
freedom of these theories. This result also holds for G_2^{+++} and we argue
that the non-linear realisation of this algebra accounts precisely for the form
fields present in the corresponding supersymmetric theory. We also find a
simple necessary condition for the roots to belong to a G^{+++} algebra.Comment: 35 pages. v2: 2 appendices added, other minor corrections. v3: tables
corrected, other minor changes, one appendix added, refs. added. Version
published in Class. Quant. Gra
K(E10), Supergravity and Fermions
We study the fermionic extension of the E10/K(E10) coset model and its
relation to eleven-dimensional supergravity. Finite-dimensional spinor
representations of the compact subgroup K(E10) of E(10,R) are studied and the
supergravity equations are rewritten using the resulting algebraic variables.
The canonical bosonic and fermionic constraints are also analysed in this way,
and the compatibility of supersymmetry with local K(E10) is investigated. We
find that all structures involving A9 levels 0,1 and 2 nicely agree with
expectations, and provide many non-trivial consistency checks of the existence
of a supersymmetric extension of the E10/K(E10) coset model, as well as a new
derivation of the `bosonic dictionary' between supergravity and coset
variables. However, there are also definite discrepancies in some terms
involving level 3, which suggest the need for an extension of the model to
infinite-dimensional faithful representations of the fermionic degrees of
freedom.Comment: 50 page
E11, generalised space-time and equations of motion in four dimensions
We construct the non-linear realisation of the semi-direct product of E11 and
its first fundamental representation at low levels in four dimensions. We
include the fields for gravity, the scalars and the gauge fields as well as the
duals of these fields. The generalised space-time, upon which the fields
depend, consists of the usual coordinates of four dimensional space-time and
Lorentz scalar coordinates which belong to the 56-dimensional representation of
E7. We demand that the equations of motion are first order in derivatives of
the generalised space-time and then show that they are essentially uniquely
determined by the properties of the E11 Kac-Moody algebra and its first
fundamental representation. The two lowest equations correctly describe the
equations of motion of the scalars and the gauge fields once one takes the
fields to depend only on the usual four dimensional space-time
The topology of U-duality (sub-)groups
We discuss the topology of the symmetry groups appearing in compactified
(super-)gravity, and discuss two applications. First, we demonstrate that for 3
dimensional sigma models on a symmetric space G/H with G non-compact and H the
maximal compact subgroup of G, the possibility of oxidation to a higher
dimensional theory can immediately be deduced from the topology of H. Second,
by comparing the actual symmetry groups appearing in maximal supergravities
with the subgroups of SL(32,R) and Spin(32), we argue that these groups cannot
serve as a local symmetry group for M-theory in a formulation of de Wit-Nicolai
type.Comment: 18 pages, LaTeX, 1 figure, 2 table
The local symmetries of M-theory and their formulation in generalised geometry
In the doubled field theory approach to string theory, the T-duality group is
promoted to a manifest symmetry at the expense of replacing ordinary Riemannian
geometry with generalised geometry on a doubled space. The local symmetries are
then given by a generalised Lie derivative and its associated algebra. This
paper constructs an analogous structure for M-theory. A crucial by-product of
this is the derivation of the physical section condition for M-theory
formulated in an extended space.Comment: 20 pages, v2: Author Name corrected, v3: typos correcte
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