scholarly journals The Modular Invariant Regularization Method and One-Loop Corrected Effective Action in the Closed Bosonic String in D=26

1989 ◽  
Vol 82 (4) ◽  
pp. 804-812 ◽  
Author(s):  
M. Abe
Keyword(s):  
Effective Action ◽  
Regularization Method ◽  
Bosonic String ◽  
Modular Invariant ◽  
Invariant Regularization ◽  
Closed Bosonic String

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 CLOSED BOSONIC STRING PARTITION FUNCTION IN TIME INDEPENDENT EXACT pp-WAVE BACKGROUND

2006 ◽  
Vol 21 (05) ◽  
pp. 995-1013
Author(s):  
AGAPITOS HATZINIKITAS ◽  
IOANNIS SMYRNAKIS
Keyword(s):  
Partition Function ◽  
Light Cone ◽  
Free Field ◽  
Bosonic String ◽  
Covariant Form ◽  
Modular Invariant ◽  
Light Cone Gauge ◽  
Axion Field ◽  
Pp Wave ◽  
Closed Bosonic String

The modular invariance of the one-loop partition function of the closed bosonic string in four dimensions in the presence of certain homogeneous exact pp -wave backgrounds is studied. In the absence of an axion field, the partition function is found to be modular invariant and equal to the free field partition function. The partition function remains unchanged also in the presence of a fixed axion field. However, in this case, the covariant form of the action suggests summation over all possible twists generated by the axion field. This is shown to modify the partition function. In the light-cone gauge, the axion field generates twists only in the worldsheet σ-direction, so the resulting partition function is not modular invariant, hence wrong. To obtain the correct partition function one needs to sum over twists in the t-direction as well, as suggested by the covariant form of the action away from the light-cone gauge.

OPEN STRINGS AS Z2-ORBIFOLDS OF CLOSED STRINGS

1991 ◽  
Vol 06 (27) ◽  
pp. 2483-2496
Author(s):  
GREG NAGAO
Keyword(s):  
Open String ◽  
Closed String ◽  
Bosonic String ◽  
Modular Invariant ◽  
Open Strings ◽  
Loop Expansion ◽  
Invariant Formulation ◽  
Closed Bosonic String ◽  
String Theories

We present a modular invariant formulation of the open string in terms of the closed string. Chan–Paton factors are understood as multiplicities which arise from a factorization of the closed string. This interpretation of the Chan–Paton factors suggests that the SO (2D/2) open string is consistent to all orders of the loop expansion. We show that the open string may be viewed as a Z2-orbifold of the closed string. Relations are found between various string theories which seem to reinforce an earlier suggestion by Freund that all string theories are derivable from the D = 26 orientable closed bosonic string.

On the closed bosonic string effective action

1990 ◽  
Vol 247 (2-3) ◽  
pp. 280-288
Author(s):  
J. García-Bellido ◽  
M. Quirós
Keyword(s):  
Effective Action ◽  
Bosonic String ◽  
Closed Bosonic String

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.

STRING EQUATIONS OF MOTION FROM VANISHING CURVATURE

1991 ◽  
Vol 06 (08) ◽  
pp. 1319-1333 ◽  
Author(s):  
MARK J. BOWICK ◽  
KONG-QING YANG
Keyword(s):  
Vector Bundles ◽  
Adiabatic Approximation ◽  
Equations Of Motion ◽  
Bosonic String ◽  
Complex Structures ◽  
Closed Bosonic String

The equations of motion for the massless modes of the closed bosonic string are obtained in the adiabatic approximation from the requirement of the vanishing of the curvature of appropriate vector bundles over the space of complex structures Diff S1/S1. This vanishing is required for physical states to be independent of string parametrization.

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.

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