摘要:

We study exact metrics on non-compact manifolds with exceptional holonomySpin(7),G2.We derive the metrics by using the formulation with vector fields. We point out that the coordinates on coset spaces are useful to handle the metrics. The coset construction also ensures that the metrics are the solutions of the self-duality condition for the spin connection. Then we conjecture the classification of spacesR×G/HwithSpin(7) holonomy. Finally, we comment on the coset construction of metrics withSU(3)holonomy. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454372

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

We propose a new way of second quantizing string theory. The method is based on considering the Fock space of strings described by constituents which make up theXR&mgr;and theXL&mgr;i.e. the right and left mover modes separately. A state with any number of strings get represented by the Cartesian product of two free particle Fock spaces, one for right mover degrees of freedom, and one for left. The resulting string field theory is a free theory. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454373

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

We study the matter part of the algebra of open string fields using the 3-string vertex over the sliver state, which we call “comma vertex.” We show that the matter part of open string fields can be written as matrices. This talk is based on [1]. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454374

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

A new simple mechanism for SUSY breaking is proposed due to the coexistence of BPS domain walls. It is assumed that our world is on a BPS domain wall and that the other BPS wall breaks the SUSY preserved by our wall. This mechanism requires no messenger fields nor complicated SUSY breaking sector on any of the walls. We obtain anN=1model in four dimensions which has an exact solution of a stable non-BPS configuration of two walls . We propose that the overlap of the wave functions of the N-G fermion and those of physical fields provides a practical method to evaluate SUSY breaking mass splitting on our wall thanks to a low-energy theorem. This is based on our recent works hep-th/0009023 and hep-th/0107204. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454375

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

In my talk I shall consider the mechanism ofself-expansionof a system of N D0-branes into high-dimensional non-commutative world-volume investigated by Harmark and Savvidy in [1]. Here D2-brane is formed due to the internal angular momentum of D0-brane system. The idea is that attractive force of tension should be cancelled by the centrifugal motion preventing a D-brane system from collapse to a lower-dimensional one. I shall also present a new extended solution where a total of 9 space dimensions is used to embed a D0-brane system. In the last section, by performing linear analysis, the stability of the system is demonstrated. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454376

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

In this lecture, I review the use of the AdS/CFT correspondence to compute the expectation value of the Wilson loop inN=4supersymmetric Yang-Mills theory. I also review some perturbative computations of the same quantity which can be summed to all orders and used to check the AdS/CFT results. I further discuss some similar computations for corrleators of the Wilson loop with chiral primary operators. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454377

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

We describe orientifold operation defining O3 plane in the conifold background by deriving it from that of O4 plane in the Type IIA brane construction by T-duality. We find that bothO3+andO3−are at the tip of the cone so that there is no net untwisted RR charge. RG analysis shows that we need two “fractional” branes for the conformal invariance in orientifolded conifold. We describe the deformation of the moduli space of the field theory in the presence of the orientifold. The finitely resolved conifold does not allow the orientifold, while deformed conifold leaves us an unresolved issue on supersymmetry. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454378

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

It is proposed that theCH−dWHN−BFSSmatrix model may be interpreted as non-local hidden variables theories in which the quantum observables are the eigenvalues of the matrices while their entries are the hidden variables. This is shown by studying the matrix model at finite temperature, withTtaken to scale as1/N.For large but finiteNthe eigenvalues of the matrices undergo Brownian motion around theN→∞limit, with diffusion constant of order1/N.The resulting probability density and current for the eigenvalues are then found to evolve in agreement with the Schroedinger equation, to leading order in1/N,with ℏ proportional to the thermal diffusion constant for the matrix elements. The quantum fluctuations and uncertainties in the positions of the eigenvalues are then consequences of ordinary statistical fluctuations in the values of the matrix elements. The derivation makes use of Nelson’s stochastic formulation of quantum theory, which is expressed in terms of a variational principle. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454379

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

We analyze supermembrane instantons (fully wrapped supermembranes) by computing the partition function of the three-dimensional supersymmetricU(N)matrix model under periodic boundary conditions. By mapping the model to a cohomological field theory and considering a mass-deformation of the model, we show that the partition function exactly leads to the U-duality invariant measure factor entering supermembrane instanton sums. On the other hand, a computation based on the quasi-classical assumption gives the non U-duality invariant result of the zero-mode analysis by Pioline &etal; [2]. This is suggestive of the importance of supermembrane self-interactions and shows a crucial difference from the matrix string case. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454380

出版商:AIP    

年代:1902

数据来源: AIP

摘要:

We consider closed superstrings in Melvin-type magnetic backgrounds. In the case of NS-NS backgrounds, these are exactly solvable as weakly coupled string models with spectrum containing tachyonic modes. Magnetic field allows one to interpolate between free superstring theories with periodic and antiperiodic boundary conditions for the fermions around some compact direction, and, in particular, between type 0 and type II string theories. Using “9–11” flip, this interpolation can be extended to M-theory and may be used to study the issue of tachyon condensation in type 0 string theory. We review related duality proposals, and, in particular, suggest a description of type 0 theory in terms of M-theory in a curved magnetic flux background in which the type 0 tachyon appears to correspond to a state ind=11supergravity fluctuation spectrum. ©2002 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1454381

出版商:AIP    

年代:1902

数据来源: AIP