scholarly journals STRING-LOOP CORRECTIONS TO EFFECTIVE ACTION AND BLACK HOLE INSTABILITIES

1995 ◽  
Vol 10 (07) ◽  
pp. 575-585
Author(s):  
V. V. BELOKUROV ◽  
M. Z. IOFA
Keyword(s):  
Black Hole ◽  
String Theory ◽  
Effective Action ◽  
Black Hole Solution ◽  
Bosonic String ◽  
Superstring Theory ◽  
Integration Measure ◽  
String Loop ◽  
Bosonic String Theory ◽  
Closed Bosonic String

Following the ideas of Ref. 3, to account for instability of 2-D black hole solution, we discuss possible imaginary string-loop corrections to the coefficient at the Einstein term in string effective action (EA). In closed bosonic string theory, such corrections appear because of the tachyon contribution to the integration measure over the moduli. In superstring theory, several possible sources of complex one-string-loop contributions to the EA are considered. It is argued that none of them can account for complex corrections to the Einstein term in the effective action.

scholarly journals GRAVITY ON NONCOMMUTATIVE D-BRANES

2003 ◽  
Vol 18 (07) ◽  
pp. 1051-1066 ◽  
Author(s):  
F. ARDALAN ◽  
H. ARFAEI ◽  
M. R. GAROUSI ◽  
A. GHODSI
Keyword(s):  
String Theory ◽  
Effective Action ◽  
Low Energy ◽  
Bosonic String ◽  
First Order ◽  
Energy Scattering ◽  
Bosonic String Theory ◽  
Brane Action

The effective action for the low energy scattering of two gravitons with a D-brane in the presence of a constant antisymmetric B field in bosonic string theory is calculated and the modification to the standard D-brane action to first order in α′ is obtained.

scholarly journals Effective action of bosonic string theory at order $$\alpha '^2$$

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
Mohammad R. Garousi
Keyword(s):  
String Theory ◽  
Effective Action ◽  
Gauge Invariance ◽  
Bosonic String ◽  
Duality Transformations ◽  
S Matrix ◽  
Minimum Number ◽  
Bosonic String Theory

Abstract Recently, it has been shown that the gauge invariance requires the minimum number of independent couplings for B-field, metric and dilaton at order $$\alpha '^2$$α′2 to be 60. In this paper we fix the corresponding 60 parameters in string theory by requiring the couplings to be invariant under the global T-duality transformations. The Riemann cubed terms are exactly the same as the couplings that have been found by the S-matrix calculations.

scholarly journals A TOY MODEL OF CLOSED STRING TACHYON EFFECTIVE ACTION

2005 ◽  
Vol 20 (07) ◽  
pp. 1481-1493
Author(s):  
J. KLUSOŇ
Keyword(s):  
Exact Solution ◽  
String Theory ◽  
Effective Action ◽  
Flat Space ◽  
Closed String ◽  
Space Time ◽  
Bosonic String ◽  
Two Dimensional ◽  
Linear Dilaton ◽  
Bosonic String Theory

In this paper we propose the toy model of the closed string tachyon effective action that has marginal tachyon profile as its exact solution in case of constant or linear dilaton background. Then we will apply this model for description of two-dimensional bosonic string theory. We will find that the background configuration with the spatial dependent linear dilaton, flat space–time metric and marginal tachyon profile is the exact solution of our model even if we take into account backreaction of tachyon on dilaton and on metric.

HIGHER DIMENSIONAL COSMOLOGY WITH STRING VACUUM ENERGY

1987 ◽  
Vol 02 (05) ◽  
pp. 299-306 ◽  
Author(s):  
H. NISHIMURA ◽  
M. TABUSE
Keyword(s):  
String Theory ◽  
Vacuum Energy ◽  
Bosonic String ◽  
Extra Space ◽  
Higher Dimensional Cosmology ◽  
Higher Dimensional ◽  
Bosonic String Theory ◽  
The One ◽  
Closed Bosonic String

We consider higher dimensional cosmology based on the closed bosonic string theory with the one-loop vacuum energy. It is concluded that the winding-effect of strings around tori has a chance to prevent the extra space from expanding, even though the curvature of torus is zero.

VERTEX OPERATORS FOR THE CLOSED BOSONIC STRING THEORY AT ARBITRARY GENUS IN THE OPERATOR FORMALISM

1990 ◽  
Vol 05 (12) ◽  
pp. 2391-2409 ◽  
Author(s):  
ADRIAN R. LUGO
Keyword(s):  
String Theory ◽  
Bosonic String ◽  
Integral Approach ◽  
Vertex Operators ◽  
Operator Formalism ◽  
Covariant Derivatives ◽  
Bosonic String Theory ◽  
Dilaton Coupling ◽  
Derivatives Of ◽  
Closed Bosonic String

A systematic procedure for constructing vertex operators for the physical states of the closed bosonic string theory at genus g in the operator formalism is presented. The method is based on imposing suitable commutation relations with the generators of the conformal transformations required by unitarity of scattering amplitudes. An Arakelov-type metric on the Riemann surface naturally arises in the case of the tachyon, which allows to define vertex operators at higher levels via covariant derivatives. They involve covariant derivatives of the curvature with respect to this metric as it happens in the path integral approach. As a particular result, the Fradkin-Tseytlin dilaton coupling is obtained.

Multiloop divergences in the closed bosonic string theory

1986 ◽  
Vol 168 (3) ◽  
pp. 207-211 ◽  
Author(s):  
E. Gava ◽  
R. Iengo ◽  
T. Jayaraman ◽  
R. Ramachandran
Keyword(s):  
String Theory ◽  
Bosonic String ◽  
Bosonic String Theory ◽  
Closed Bosonic String

COVARIANT BASIC OPERATORS IN BOSONIC STRING THEORY

1989 ◽  
Vol 04 (04) ◽  
pp. 857-871 ◽  
Author(s):  
G. CRISTOFANO ◽  
F. NICODEMI ◽  
R. PETTORINO
Keyword(s):  
String Theory ◽  
Vacuum Energy ◽  
Bosonic String ◽  
Covariant Formulation ◽  
Loop Level ◽  
Integration Measure ◽  
Bosonic String Theory

We discuss the covariant formulation of basic one-loop operators for the bosonic string using BRST invariant 3-Reggeon Vertex and propagator. In particular we discuss their automorphic structure and we give the construction of the vacuum energy and the tadpole operator at two-loop level writing explicitly the integration measure.

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