scholarly journals TWO-LOOP WORLDSHEET EFFECTIVE ACTION

2003 ◽  
Vol 18 (39) ◽  
pp. 2817-2828 ◽  
Author(s):  
A. R. FAZIO ◽  
G. K. SAVVIDY
Keyword(s):  
String Theory ◽  
Effective Action ◽  
String Tension ◽  
Second Order ◽  
Quantum Corrections ◽  
Loop Correction ◽  
Classical Level ◽  
Loop Expansion

We are studying quantum corrections in the earlier proposed string theory based on worldsheet action which measures the linear sizes of the surfaces. At classical level the string tension is equal to zero and as it was demonstrated in the previous studies one loop correction to the classical worldsheet action generates Nambu–Goto area term, that is nonzero string tension. We extend this analysis computing the worldsheet effective action in the second order of the loop expansion. We are studying quantum corrections in the earlier proposed string theory based on worldsheet action which measures the perimeter of the surface. At the classical level the string tension is equal to zero and we demonstrate that one and two-loop corrections to the classical worldsheet action generates Nambu–Goto area term, that is nonzero string tension.

Infrared finiteness of the two-loop correction to the Chern–Simons term in the Yang–Mills–Chern–Simons theory

1995 ◽  
Vol 73 (5-6) ◽  
pp. 344-348 ◽  
Author(s):  
Yeong-Chuan Kao ◽  
Hsiang-Nan Li
Keyword(s):  
Effective Action ◽  
Background Field ◽  
Landau Gauge ◽  
Quantum Corrections ◽  
Simons Theory ◽  
Loop Correction ◽  
Loop Contribution ◽  
Yang Mills ◽  
Chern Simons ◽  
Chern Simons Theory

We show that the two-loop contribution to the coefficient of the Chern–Simons term in the effective action of the Yang–Mills–Chern–Simons theory is infrared finite in the background field Landau gauge. We also discuss the difficulties in verifying the conjecture, due to topological considerations, that there are no more quantum corrections to the Chern–Simons term other than the well-known one-loop shift of the coefficient.

scholarly journals Derive Lovelock gravity from string theory in cosmological background

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Peng Wang ◽  
Houwen Wu ◽  
Haitang Yang ◽  
Shuxuan Ying
Keyword(s):  
String Theory ◽  
Effective Action ◽  
Strong Support ◽  
Effective Theory ◽  
Quadratic Term ◽  
Lovelock Gravity ◽  
Cosmological Background ◽  
Finite Term ◽  
Specific Dimension ◽  
Bonnet Term

Abstract It was proved more than three decades ago, that the first order α′ correction of string effective theory could be written as the Gauss-Bonnet term, which is the quadratic term of Lovelock gravity. In cosmological background, with an appropriate field redefinition, we reorganize the infinite α′ corrections of string effective action into a finite term expression for any specific dimension. This finite term expression matches Lovelock gravity exactly and thus fix the couplings of Lovelock gravity by the coefficients of string effective action. This result thus provides a strong support to string theory.

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.

RENORMALIZATION GROUP EQUATION AND EFFECTIVE ACTION IN STRING THEORY

1989 ◽  
Vol 04 (10) ◽  
pp. 941-951 ◽  
Author(s):  
J. GAITE
Keyword(s):  
Renormalization Group ◽  
String Theory ◽  
Effective Action ◽  
Renormalization Group Equation ◽  
Group Equation ◽  
Generating Functional ◽  
S Matrix

The connection between the renormalization group for the σ-model effective action for the Polyakov string and the S-matrix generating functional for dual amplitudes is studied. A more general approach to the renormalization group equation for string theory is proposed.

scholarly journals FROM p-BRANES TO COSMOLOGY

1999 ◽  
Vol 14 (26) ◽  
pp. 4121-4142 ◽  
Author(s):  
H. LÜ ◽  
S. MUKHERJI ◽  
C. N. POPE
Keyword(s):  
String Theory ◽  
Effective Action ◽  
Dimensional Reduction ◽  
Cosmological Models ◽  
Cosmological Solutions ◽  
M Theory ◽  
The Relationship

We study the relationship between static p-brane solitons and cosmological solutions of string theory or M theory. We discuss two different ways in which extremal p-branes can be generalized to nonextremal ones, and show how wide classes of recently discussed cosmological models can be mapped into nonextremal p-brane solutions of one of these two kinds. We also extend previous discussions of cosmological solutions to include some that make use of cosmological-type terms in the effective action that can arise from the generalized dimensional reduction of string theory or M theory.

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 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.

ONE-LOOP CORRECTION TO ENERGY OF SPINNING STRINGS IN AdS5×T1, 1

2012 ◽  
Vol 27 (03) ◽  
pp. 1250015
Author(s):  
HYOJOONG KIM ◽  
NAKWOO KIM ◽  
JUNG HUN LEE
Keyword(s):  
Field Theory ◽  
Mode Frequency ◽  
Harmonic Oscillators ◽  
Quantum Corrections ◽  
Gauge Field Theory ◽  
Leading Order ◽  
Loop Correction ◽  
Conformal Dimension ◽  
Normal Mode Frequency ◽  
The One

We consider circular spinning string solutions in AdS5×T1, 1 and calculate the quantum corrections to the energy at one-loop on worldsheet. The fluctuations are given as a set of harmonic oscillators and we calculate their normal mode frequency in closed form. The sum of frequency is equal to the one-loop string energy, which through AdS/CFT correspondence corresponds to the leading order correction of the conformal dimension for long operators in Klebanov–Witten conifold gauge field theory.

scholarly journals A NOTE ON DUALITIES IN EINSTEIN'S GRAVITY IN THE PRESENCE OF A NON-MINIMALLY COUPLED SCALAR FIELD

2003 ◽  
Vol 18 (15) ◽  
pp. 1043-1051 ◽  
Author(s):  
L. R. ABRAMO ◽  
L. BRENIG ◽  
E. GUNZIG ◽  
ALBERTO SAA
Keyword(s):  
Scalar Field ◽  
String Theory ◽  
Effective Action ◽  
Low Energy ◽  
Conformal Transformations ◽  
Spacetime Curvature

We show that the action of Einstein's gravity with a scalar field coupled in a generic way to spacetime curvature is invariant under a particular set of conformal transformations. These transformations relate dual theories for which the effective couplings of the theory are scaled uniformly. In the simplest case, this class of dualities reduces to the S-duality of low-energy effective action of string theory.

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