scholarly journals Unitarity Problem in Nonlocal Field Theories: Some Remarks on String Field Theory

1988 ◽  
Vol 80 (3) ◽  
pp. 566-581 ◽  
Author(s):  
S. Tanaka
Keyword(s):  
Field Theory ◽  
String Field Theory ◽  
Field Theories ◽  
Nonlocal Field

scholarly journals Nonlocal inflationThis paper was prsented at the Theory CANADA 4 conference, held at the Centre de Recherches Mathématiques at the Université de Montréal, Québec, Canada on 4–7 June 2008.

2009 ◽  
Vol 87 (3) ◽  
pp. 189-194 ◽  
Author(s):  
Neil Barnaby
Keyword(s):  
Field Theory ◽  
Cosmic Microwave Background ◽  
String Field Theory ◽  
Initial Value Problem ◽  
High Derivative ◽  
Field Theories ◽  
Microwave Background ◽  
Initial Value ◽  
Nonlocal Field

We consider the possibility of realizing inflation in nonlocal field theories containing infinitely many derivatives. Such constructions arise naturally in string field theory and also in a number of toy models, such as the p-adic string. After reviewing the complications (ghosts and instabilities) that arise when working with high-derivative theories, we discuss the the initial value problem and perturbative stability of theories with infinitely many derivatives. Next, we examine the inflationary dynamics and phenomenology of such theories. Nonlocal inflation can proceed even when the potential is naively too steep and generically predicts large non-Gaussianity in the cosmic microwave background.

scholarly journals Mapping between Witten and lightcone string field theories

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Theodore Erler ◽  
Hiroaki Matsunaga
Keyword(s):  
Field Theory ◽  
String Field Theory ◽  
Bosonic String ◽  
Field Theories

Abstract We propose a transformation between the off-shell field variables of Witten’s open bosonic string field theory and the traditional lightcone string field theory of Kaku and Kikkawa, based on Mandelstam’s interacting string picture. This is accomplished by deforming the Witten vertex into lightcone cubic and quartic vertices, followed by integrating out the ghost and lightcone oscillator excitations from the string field. Surprisingly, the last step does not alter the cubic and quartic interactions and does not generate effective vertices, and leads precisely to Kaku and Kikkawa’s lightcone string field theory.

scholarly journals PHYSICAL DEGREES OF FREEDOM IN 2D STRING FIELD THEORIES

1992 ◽  
Vol 07 (37) ◽  
pp. 3479-3486
Author(s):  
NORISUKE SAKAI ◽  
YOSHIAKI TANII
Keyword(s):  
Field Theory ◽  
Master Equation ◽  
String Field Theory ◽  
Degrees Of Freedom ◽  
Field Theories ◽  
Relative Cohomology ◽  
Component Decomposition ◽  
The Absolute

States in the absolute (semi-relative) cohomology but not in the relative cohomology are examined through the component decomposition of the string field theory action for the 2D string. It is found that they are auxiliary fields without kinetic terms, but are important for instance in the master equation for the Ward-Takahashi identities. The ghost structure is analyzed in the Siegel gauge, but it is noted that the absolute (semi-relative) cohomology states are lost.

scholarly journals Tree-level S-matrix of superstring field theory with homotopy algebra structure

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Hiroshi Kunitomo
Keyword(s):  
Field Theory ◽  
String Field Theory ◽  
Heterotic String ◽  
Field Theories ◽  
Tree Level ◽  
Algebra Structure ◽  
Type Ii ◽  
S Matrix ◽  
Homotopy Algebra

Abstract We show that the tree-level S-matrices of the superstring field theories based on the homotopy-algebra structure agree with those obtained in the first-quantized formulation. The proof is given in detail for the heterotic string field theory. The extensions to the type II and open superstring field theories are straightforward.

scholarly journals RECENT DEVELOPMENTS IN D=2 STRING FIELD THEORY

1994 ◽  
Vol 09 (18) ◽  
pp. 3103-3141 ◽  
Author(s):  
MICHIO KAKU
Keyword(s):  
Field Theory ◽  
String Field Theory ◽  
Correlation Functions ◽  
Two Dimensions ◽  
Field Theories ◽  
Fermion Field ◽  
Free Fermion ◽  
Temporal Gauge ◽  
Recent Developments ◽  
The Relationship

We review the recent developments in the construction of string field theory in two dimensions. We analyze the bewildering number of string field theories that have been proposed, all of which correctly reproduce the correlation functions of two-dimensional string theory. These include (1) free fermion field theory, (2) collective string field theory, (3) temporal gauge string field theory and (4) nonpolynomial string field theory. We will analyze discrete states, the ω(∞) symmetry, and correlation functions in terms of these different string field theories. We will also comment on the relationship between these field theories, which is still not well understood.

LOOP CALCULATIONS IN TWO-DIMENSIONAL NONLOCAL FIELD THEORIES

1992 ◽  
Vol 07 (23) ◽  
pp. 5891-5915 ◽  
Author(s):  
M.T. GRISARU ◽  
P. VAN NIEUWENHUIZEN
Keyword(s):  
Field Theory ◽  
Local Field ◽  
Momentum Space ◽  
Field Theories ◽  
Two Dimensional ◽  
Local Field Theory ◽  
Nonlocal Action ◽  
Nonlocal Field

We perform one-loop calculations in chiral induced W3 gravity in momentum space. Unlike a previous one-loop calculation in x space, which reduced the problem to one in local field theory, we work directly with the nonlocal action. We use Polyakov’s exponential regularization, and obtain agreement with the x-space calculation. We discuss the extension of our methods to higher-loop calculations in more-general chiral nonlocal field theories.

Beyond the Standard Model

2017 ◽  
Author(s):  
Laurent Baulieu ◽  
John Iliopoulos ◽  
Roland Sénéor
Keyword(s):  
Field Theory ◽  
General Relativity ◽  
Supergravity Models ◽  
Standard Model ◽  
Field Theories ◽  
Beyond The Standard Model ◽  
Super Symmetry ◽  
The Standard Model ◽  
Topological Field ◽  
Supersymmetric Theories

The motivation for supersymmetry. The algebra, the superspace, and the representations. Field theory models and the non-renormalisation theorems. Spontaneous and explicit breaking of super-symmetry. The generalisation of the Montonen–Olive duality conjecture in supersymmetric theories. The remarkable properties of extended supersymmetric theories. A brief discussion of twisted supersymmetry in connection with topological field theories. Attempts to build a supersymmetric extention of the standard model and its experimental consequences. The property of gauge supersymmetry to include general relativity and the supergravity models.

scholarly journals Gauged double field theory as an L∞ algebra

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Eric Lescano ◽  
Martín Mayo
Keyword(s):  
Field Theory ◽  
Algebraic Structure ◽  
Classical Field ◽  
Field Theories ◽  
Lie Derivative ◽  
Linear Perturbation ◽  
Double Field Theory ◽  
Generalized Frame ◽  
Symmetry Transformations ◽  
Classical Field Theories

Abstract L∞ algebras describe the underlying algebraic structure of many consistent classical field theories. In this work we analyze the algebraic structure of Gauged Double Field Theory in the generalized flux formalism. The symmetry transformations consist of a generalized deformed Lie derivative and double Lorentz transformations. We obtain all the non-trivial products in a closed form considering a generalized Kerr-Schild ansatz for the generalized frame and we include a linear perturbation for the generalized dilaton. The off-shell structure can be cast in an L3 algebra and when one considers dynamics the former is exactly promoted to an L4 algebra. The present computations show the fully algebraic structure of the fundamental charged heterotic string and the $$ {L}_3^{\mathrm{gauge}} $$ L 3 gauge structure of (Bosonic) Enhanced Double Field Theory.

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