scholarly journals Space/Time Noncommutativity in String Theories without Background Electric Field

2002 ◽  
Vol 2002 (12) ◽  
pp. 031-031 ◽  
Author(s):  
Giuseppe De Risi ◽  
Gianluca Grignani ◽  
Marta Orselli
Keyword(s):  
Electric Field ◽  
Space Time ◽  
String Theories

scholarly journals GENERALIZED W3-STRINGS FROM FREE FIELDS

1995 ◽  
Vol 10 (06) ◽  
pp. 515-524 ◽  
Author(s):  
J. M. FIGUEROA-O'FARRILL ◽  
C. M. HULL ◽  
L. PALACIOS ◽  
E. RAMOS
Keyword(s):  
Bosonic Strings ◽  
Free Field ◽  
Space Time ◽  
General Construction ◽  
Special Cases ◽  
Free Fields ◽  
Rule Out ◽  
General Conditions ◽  
String Theories

The conventional quantization of w3-strings gives theories which are equivalent to special cases of bosonic strings. We explore whether a more general quantization can lead to new generalized W3-string theories by seeking to construct quantum BRST charges directly without requiring the existence of a quantum W3-algebra. We study W3-like strings with a direct space-time interpretation — that is, with matter given by explicit free field realizations. Special emphasis is placed on the attempt to construct a quantum W-string associated with the magic realizations of the classical w3-algebra. We give the general conditions for the existence of W3-like strings, and comment on how the known results fit into our general construction. Our results are negative: we find no new consistent string theories, and in particular rule out the possibility of critical strings based on the magic realizations.

scholarly journals SCHWINGER'S RESULT ON PARTICLE PRODUCTION FROM COMPLEX PATHS WKB APPROXIMATION

2000 ◽  
Vol 15 (23) ◽  
pp. 3717-3731 ◽  
Author(s):  
S. BISWAS ◽  
A. SHAW ◽  
B. MODAK
Keyword(s):  
Electric Field ◽  
Particle Production ◽  
Complex Space ◽  
Space Time ◽  
Wkb Approximation ◽  
Uniform Electric Field ◽  
Gauge Invariant ◽  
Transmission Coefficients ◽  
Loop Approximation ◽  
Complex Trajectory

This paper presents the derivation of Schwinger's gauge-invariant result of Im ℒ eff up to one loop approximation, for particle production in an uniform electric field through the method of complex trajectory WKB approximation (CWKB). The CWKB proposed by one of the authors1 looks upon particle production as being due to the motion of a particle in complex space–time plane, thereby requiring tunneling paths both in space and time. Recently2,3 there have been some efforts to calculate the reflection and the transmission coefficients for particle production in an uniform electric field that differ from our expressions for the same. In this paper we clarify the confusion in this regard and establish the correctness of CWKB.

CHIRAL (SUPER) STRING ACTIONS

1990 ◽  
Vol 05 (07) ◽  
pp. 1341-1361 ◽  
Author(s):  
S.M. KUZENKO ◽  
O.A. SOLOVIEV
Keyword(s):  
String Theory ◽  
Space Time ◽  
Heterotic String ◽  
Bosonic String ◽  
Dimensional Case ◽  
Anomaly Cancellation ◽  
Heterotic String Theory ◽  
Covariant Action ◽  
Heterotic String Theories ◽  
String Theories

We present a covariant action describing chiral bosonic string theories in space-time dimensions d<26 and a covariant (1, 0) supersymmetric action describing heterotic string theories in space-time of dimension d<10. The anomaly cancellation conditions are found. In the four-dimensional case the supersymmetric action corresponds to the SO(44) heterotic string theory.

Characterizing space-time coupling of the electric field of ultrashort pulses using the SPIDER technique

2005 ◽  
Author(s):  
Ellen M. Kosik Williams ◽  
Christophe Dorrer ◽  
Aleksander S. Radunsky ◽  
Ian A. Walmsley
Keyword(s):  
Electric Field ◽  
Ultrashort Pulses ◽  
Space Time

scholarly journals THE ORBIFOLD-STRING THEORIES OF PERMUTATION-TYPE II: CYCLE DYNAMICS AND TARGET SPACE–TIME DIMENSIONS

2010 ◽  
Vol 25 (30) ◽  
pp. 5487-5515
Author(s):  
M. B. HALPERN
Keyword(s):  
Physical State ◽  
Central Charge ◽  
Space Time ◽  
Target Space ◽  
Twisted Sector ◽  
Time Dimension ◽  
State Problem ◽  
Dimension Formula ◽  
Charge Formula ◽  
String Theories

We continue our discussion of the general bosonic prototype of the new orbifold-string theories of permutation-type. Supplementing the extended physical-state conditions of the previous paper, we construct here the extended Virasoro generators with cycle central charge [Formula: see text], where fj(σ) is the length of cycle j in twisted sector σ. We also find an equivalent, reduced formulation of each physical-state problem at reduced cycle central charge cj(σ) = 26. These tools are used to begin the study of the target space–time dimension [Formula: see text] of cycle j in sector σ, which is naturally defined as the number of zero modes (momenta) of each cycle. The general model-dependent formulae derived here will be used extensively in succeeding papers, but are evaluated in this paper only for the simplest case of the "pure" permutation orbifolds.

RELATIVISTIC LANDAU–AHARONOV–CASHER QUANTIZATION IN TOPOLOGICAL DEFECT SPACE–TIME

2010 ◽  
Vol 19 (01) ◽  
pp. 85-96 ◽  
Author(s):  
K. BAKKE ◽  
C. FURTADO
Keyword(s):  
Dipole Moment ◽  
Electric Field ◽  
Magnetic Dipole Moment ◽  
Neutral Particle ◽  
Topological Defect ◽  
Nonrelativistic Limit ◽  
Space Time ◽  
Landau Levels ◽  
Relativistic Dynamics ◽  
Curved Space

In this paper we study the Landau levels arising within the relativistic dynamics of a neutral particle which possesses a permanent magnetic dipole moment interacting with an external electric field in the curved space–time background with the presence of a torsion field. We use the Aharonov–Casher effect to couple this neutral particle with the electric field in this curved background. The eigenfunction and eigenvalues of the Hamiltonian are obtained. We show that the presence of the topological defect breaks the infinite degeneracy of the relativistic Landau levels arising in this system. We study the nonrelativistic limit of the eigenvalues and compare these results with cases studied earlier.

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