摘要:

In this talk we show that tachyon annihilation combined with an approximation in which string theory non-commutativity structure is captured by the algebra of differential operators on space-time gives a unified approach to non-Abelian structures onD-branes, all lowest energy excitations onD-branes and all RR couplings in type II string theory. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454352

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

The physics that is traditionally formulated in one-time-physics (1T-physics) can also be formulated in two-time-physics (2T-physics). The physical phenomena in 1T or 2T physics are not different, but the spacetime formalism used to describe them is. The 2T description involves two extra dimensions (one time and one space), is more symmetric, and makes manifest many hidden features of 1T-physics. One such hidden feature is that families of apparently different 1T-dynamical systems inddimensions holographically describe the same 2T system ind+2dimensions. In 2T-physics there are two timelike dimensions, but there is also a crucial gauge symmetry that thins out spacetime, thus making 2T-physics effectively equivalent to 1T-physics. The gauge symmetry is also responsible for ensuring causality and unitarity in a spacetime with two timelike dimensions. What is gained through 2T-physics is a unification of diverse 1T dynamics by making manifest hidden symmetries and relationships among them. Such symmetries and relationships is the evidence for the presence of the underlying higher dimensional spacetime structure. 2T-physics could be viewed as a device for gaining a better understanding of 1T-physics, but beyond this, 2T-physics offers new vistas in the search of the unified theory while raising deep questions about the meaning of spacetime. In these lectures, the recent developments in the gauge field theory formulation of 2T-physics will be described after a brief review of the results obtained so far in the worldline approach. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454353

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

After reviewing the Green-Schwarz superstring using the approach of Siegel, the super-string is covariantly quantized by constructing a BRST operator from the fermionic constraints and a bosonic pure spinor ghost variable. Physical massless vertex operators are constructed and, for the first time, N-point tree amplitudes are computed in a manifestly ten-dimensional super-Poincare´ covariant manner. Quantization can be generalized to curved supergravity backgrounds and the vertex operator for fluctuations aroundAdS5×S5is explicitly constructed. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454354

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

We explain how perturbative string theory can be viewed as an exactly renormalizable Weyl invariant quantum mechanics in the worldsheet representation clarifying why string scattering amplitudes are both finite and unambiguously normalized and explaining the origin of UV-IR relations in spacetime. As applications we examine the worldsheet representation of off-shell string amplitudes and of nonperturbative type IB states. We conclude with an analysis of the equilibrium thermodynamics of free strings establishing the absence of the Hagedorn phase transition. We show that both of the 10D heterotic strings have a stable finite temperature ground state with gauge groupSO(16)×SO(16).The free energy at the Kosterlitz-Thouless phase transition is minimized with finite entropy and positive specific heat. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454355

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

We review the construction of regularp-brane solutions of M-theory and string theory with less than maximal supersymmetry whose transverse spaces have metrics with special holonomy, and where additional fluxes allow brane resolutions via transgression terms. We summarize the properties of resolved M2-branes and fractional D2-branes, whose transverse spaces are Ricci flat eight-dimensional and seven-dimensional spaces of special holonomy. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454356

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

We argue that the gauge-invariant operators on non-commutative branes which couple to different modes of the closed bosonic string are in one-to-one correspondence with the operators which appear in a harmonic expansion of an open Wilson line, defined on an arbitrary contour, around a certain straight line contour. An analogue of the level matching condition on the gauge theory operators emerges quite naturally from the cyclic symmetry of the straight Wilson line. Moreover, the generating functional of the correlation functions of these operators has the space-time gauge symmetry that one expects to find in the closed bosonic string field theory at the linearized level. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454357

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

Noncommutative geometry governs the physics of quantum Hall (QH) effects. The Hamiltonian is not local: It is constructed on a von Neumann lattice. Noncommutative geometry leads to a spontaneous development of quantum coherence. As coherent excitations there arise isospin waves and topological solitons (skyrmions). It leads to a Josephson-like effect in a bilayer system. We expect SU(2N) quantum coherence andCP2N−1skyrmions inN-layer QH systems in general. QH effects present experimental tests of various ideas inherent to noncommutative geometry. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454358

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

In this talk I review some aspects of the idea that there is an infra-red conformal fixed-point at the TeV scale. In particular, it is shown how gauge coupling unification can be achieved by TeV unification in a semi-simple gauge group. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454359

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454360

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

In this paper we discuss deformations of the BRST operator of the fermionic string. These deformations preserve nilpotency of the BRST operator and correspond to turning on infinitesimal Gravitino and Ramond-Ramond spacetime fields. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454361

出版商:AIP    

年代:1902

数据来源: AIP