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 T-DUALITY OF NSR SUPERSTRING: THE WORLDSHEET PERSPECTIVE

2012 ◽  
Vol 27 (23) ◽  
pp. 1250140 ◽  
Author(s):  
JNANADEVA MAHARANA
Keyword(s):  
Equations Of Motion ◽  
Bosonic String ◽  
Target Space ◽  
Vertex Operators ◽  
Covariant Form ◽  
Dimensional Torus ◽  
Duality Symmetry ◽  
Superspace Formalism ◽  
Closed Bosonic String ◽  
Equations Of Motions

We formulate target space duality symmetry of NSR superstring from the perspectives of worldsheet. The worldsheet action is presented in the superspace formalism in the presence of massless backgrounds. We start from a [Formula: see text]-dimensional target space worldsheet action and compactify the theory on a d-dimensional torus, Td. It is assumed that the backgrounds are independent of compact (super)coordinates. We adopt the formalism of our earlier work to introduce dual supercoordinates along compact directions and introduce the corresponding dual backgrounds. It is demonstrated that combined equations of motion of the two sets of coordinates can be expressed in a manifestly O(d, d) covariant form analogous to the equations of motions for closed bosonic string derived by us. Furthermore, we show that the vertex operators associated with excited massive levels of NSR string can be expressed in an O(d, d) invariant form generalizing earlier result for closed bosonic string.

GENERALIZED CANONICAL QUANTIZATION OF BOSONIC STRING IN BACKGROUND FIELDS

1991 ◽  
Vol 06 (07) ◽  
pp. 1211-1231 ◽  
Author(s):  
I.L. BUCHBINDER ◽  
E.S. FRADKIN ◽  
S.L. LYAKHOVICH ◽  
V.D. PERSHIN
Keyword(s):  
Quantum Correction ◽  
Equations Of Motion ◽  
Canonical Quantization ◽  
Virasoro Algebra ◽  
Bosonic String ◽  
Classical Formulation ◽  
Weyl Ordering ◽  
Wick Ordering ◽  
Background Fields ◽  
Closed Bosonic String

The theory of a closed bosonic string interacting with background fields, namely, with metric, antisymmetric tensor of second rank and dilaton, is considered. The classical formulation of the constrained theory is developed and the canonical quantization is carried out. The combined symbols of the Virasoro operators corresponding to the Weyl ordering of zero string modes and to the Wick ordering of oscillating ones are constructed. The quantum Virasoro algebra is formulated by means of star-commutators corresponding to these symbols and the nonlocal first quantum correction in the algebra is calculated. The local part of the correction linear in curvature is derived and effective equations of motion for background fields are obtained in the lowest order.

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.

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