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Strings, Branes and Non-trivial Space-times
Karlstad University, Faculty of Technology and Science, Department of Physics and Electrical Engineering.
2008 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

This thesis deals with different aspects of string and /p/-brane theories. One of the motivations for string theory is to unify the forces in nature and produce a quantum theory of gravity. /p/-branes and related objects arise in string theory and are related to a non-perturbative definition of the theory. The results of this thesis might help in understanding string theory better. The first part of the thesis introduces and discusses relevant topics for the second part of the thesis which consists of five papers.

In the three first papers we develop and treat a perturbative approach to relativistic /p/-branes around stretched geometries. The unperturbed theory is described by a string- or particle-like theory. The theory is solved, within perturbation theory, by constructing successive canonical transformations which map the theory to the unperturbed one order by order. The result is used to define a quantum theory which requires for consistency d = 25 + p dimensions for the bosonic /p/-branes and d = 11 for the supermembrane. This is one of the first quantum results for extended objects beyond string theory and is a confirmation of the expectation of an eleven-dimensional quantum membrane.

The two last papers deal with a gauged WZNW-approach to strings moving on non-trivial space-times. The groups used in the formulation of these models are connected to Hermitian symmetric spaces of non-compact type. We have found that the GKO-construction does not yield a unitary spectrum. We will show that there exists, however, a different approach, the BRST approach, which gives unitarity under certain conditions. This is the first example of a difference between the GKO- and BRST construction. This is one of the first proofs of unitarity of a string theory in a non-trivial non-compact space-time. Furthermore, new critical string theories in dimensions less then 26 or 10 is found for the bosonic and supersymmetric string, respectively.

Place, publisher, year, edition, pages
Karlstad: Karlstad University , 2008. , p. 116
Series
Karlstad University Studies, ISSN 1403-8099 ; 2008:20
Keywords [en]
String theory, Membranes, BRST, /p/-branes, /p/-branes, Non-compact backgrounds, WZNW-model, No-ghost theorem, Unitarity, Hermitian symmetric spaces, CFT
National Category
Physical Sciences
Research subject
Physics
Identifiers
URN: urn:nbn:se:kau:diva-1619ISBN: 978-91-7063-179-5 (print)OAI: oai:DiVA.org:kau-1619DiVA, id: diva2:5565
Public defence
2008-06-09, 1B306, 1B, Universitetsgatan 2, Karlstad, 13:15
Opponent
Supervisors
Available from: 2008-05-19 Created: 2008-05-19 Last updated: 2011-11-10
List of papers
1. Stretched quantum membranes
Open this publication in new window or tab >>Stretched quantum membranes
2005 (English)In: Nuclear Physics B, ISSN 0550-3213, E-ISSN 1873-1562, Vol. 727, no 1-2, p. 77-98Article in journal (Refereed) Published
Identifiers
urn:nbn:se:kau:diva-2033 (URN)10.1016/j.nuclphysb.2005.08.041 (DOI)
Available from: 2008-05-19 Created: 2008-05-19 Last updated: 2017-12-07Bibliographically approved
2. The BRST treatment of stretched membranes
Open this publication in new window or tab >>The BRST treatment of stretched membranes
2006 (English)In: Nuclear Physics B, ISSN 0550-3213, E-ISSN 1873-1562, Vol. 736, no 1-2, p. 156-167Article in journal (Refereed) Published
Identifiers
urn:nbn:se:kau:diva-2034 (URN)10.1016/j.nuclphysb.2005.12.004 (DOI)
Available from: 2008-05-19 Created: 2008-05-19 Last updated: 2017-12-07Bibliographically approved
3. On small tension p-branes
Open this publication in new window or tab >>On small tension p-branes
2008 (English)In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 662, no 3, p. 270-274Article in journal (Refereed) Published
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-2035 (URN)10.1016/j.physletb.2008.03.013 (DOI)
Available from: 2008-05-19 Created: 2008-05-19 Last updated: 2017-12-07Bibliographically approved
4. On the unitarity of gauged non-compact WZNW strings
Open this publication in new window or tab >>On the unitarity of gauged non-compact WZNW strings
2008 (English)In: Nuclear Physics B, ISSN 0550-3213, E-ISSN 1873-1562, Vol. 797, no 3, p. 464-498Article in journal (Refereed) Published
National Category
Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:kau:diva-2036 (URN)10.1016/j.nuclphysb.2007.11.027 (DOI)
Available from: 2008-05-19 Created: 2008-05-19 Last updated: 2017-12-07Bibliographically approved
5. On the unitarity of gauged non-compact world-sheet supersymmetric WZNW models
Open this publication in new window or tab >>On the unitarity of gauged non-compact world-sheet supersymmetric WZNW models
2009 (English)In: Nuclear Physics B, ISSN 0550-3213, E-ISSN 1873-1562, Vol. 812, no 3, p. 525-539Article in journal (Refereed) Published
Abstract [en]

In this paper we generalize our investigation of the unitarity of non-compact WZNW models connected to Hermitian symmetric spaces to the N=1 world-sheet supersymmetric extension of these models. We will prove that these models have a unitary spectrum in a BRST approach for antidominant highest weight representations if the level and weights of the gauged subalgebra are integers. We will find new critical string theories in 7 and 9 space–time dimensions.

National Category
Physical Sciences
Identifiers
urn:nbn:se:kau:diva-2037 (URN)10.1016/j.nuclphysb.2008.12.011 (DOI)
Available from: 2008-05-19 Created: 2008-05-19 Last updated: 2017-12-07Bibliographically approved

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