| 1. |
- Bengtsson, Anders K.H., et al.
(författare)
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Particles, superparticles and twistors
- 1987
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Ingår i: Phys. Rev. D36 (1987) 1766.
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Tidskriftsartikel (refereegranskat)abstract
- The covariant Green-Schwarz action for a superstring has never been quantized covariantly. The physics behind this is discussed. We then consider the corresponding point-particle action in four dimensions, and write down a master action from which it can be obtained as a gauge choice: the ‘‘space-time gauge.’’ There is also a ‘‘twistor gauge,’’ in which covariant quantization is straightforward (as noted previously by Shirafuji).
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| 2. |
- Bengtsson, Ingemar, et al.
(författare)
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Particles, twistors and the division algebras
- 1987
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Ingår i: Nucl.Phys.B302 (1988) 81.
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Tidskriftsartikel (refereegranskat)abstract
- We study twistorial mechanics of particles and super-particles in six dimensions. To this end we formulate (in a general division algebra framework) a twistor theory in D = 6 based on quaternionic numbers, and prove the equivalence between this version of particle dynamics and the ordinary one. The super-twistors define a covariant and gauge invariant concept of a super world-line and allow us to write an action for the supersymmetric particle that is not plagued by the content of second class constraints that prevents a covariant quantization in the space-time picture. The notion and geometry of projectile twistor space, and its connection to Minkowski space, are examined and shown to directly generalize the results in D = 3, 4. Quantization is performed and analytic quaternionic eigenfunctions and integrations are discussed. We also draw some conclusions on the possible generalization to ten dimensions.
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| 3. |
- Bengtsson, Ingemar, et al.
(författare)
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What's the matter with the Green-Schwarz action?
- 1987
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Ingår i: Phys.Lett.B203 (1988) 96.
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Tidskriftsartikel (refereegranskat)abstract
- The Green-Schwarz action describes only states with positive energy. We explain how this obstructs covariant quantisation.
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| 4. |
- Brink, Lars, 1943, et al.
(författare)
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String field theory with chiral coordinates
- 1987
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Ingår i: Nucl.Phys.B293 (1987) 114.
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Tidskriftsartikel (refereegranskat)abstract
- Interesting string theories, such as the heterotic string, involve chiral coordinates, that is coordinates which are either right-moving or left-moving on the world sheet. In this paper the field theoretic formulation of such theories is studied with most emphasis on the light-cone gauge method although the main techniques would also apply in the various covariant approaches to string field theory. In the heterotic string the internal symmetry is described in terms of eight left-moving complex bosonic coordinates in a manner which parallels the treatment of fermionic Grassmann coordinates. The wave functions, and hence the free string fields, are described in these coordinates and the three-string interaction is derived from the requirements of supersymmetry and Lorentz invariance both in its functional form and in terms of its oscillator modes.
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| 5. |
- Cederwall, Martin, 1961
(författare)
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An extension of the twistor concept to string theory
- 1989
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Ingår i: Phys.Lett.B226 (1989) 45.
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Tidskriftsartikel (refereegranskat)abstract
- A division algebra twistor transform for the variables of a bosonic string in D=3,4,6 or 10 is proposed. The transform is also extended with the coordinates of an “internal” Minkowski space to obtain full symmetry between internal and external spinor indices. The constraint algebra contains a Virasoro generator coupled to a Kac-Moody algebra of Lorentz transformations. The full algebra is field dependent due to non-bilinearity of the hamiltonian.
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| 6. |
- Cederwall, Martin, 1961
(författare)
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Interactions in new string theories
- 1986
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Ingår i: Phys.Lett.B191 (1987) 349.
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Tidskriftsartikel (refereegranskat)abstract
- Couplings are introduced in the recently proposed non-supersymmetric string theories containing fermions. Both the conformal/Lorentz invariance and the gravity content imply a two-derivative structure. The pomeron singularity is a pole. The structure of loop amplitudes is briefly discussed.
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| 7. |
- Cederwall, Martin, 1961
(författare)
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Jordan algebra dynamics
- 1988
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Ingår i: Phys.Lett.B210 (1988) 169.
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Tidskriftsartikel (refereegranskat)abstract
- Classical particle dynamics in spaces described by Jordan algebras is discussed, with concentration on invariances, light-likeness and twistor transforms.
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| 8. |
- Cederwall, Martin, 1961
(författare)
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Light front string Green's functionals
- 1986
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Ingår i: Nucl.Phys.B284 (1987) 386.
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Tidskriftsartikel (refereegranskat)abstract
- Functional propagators are derived for strings described by different types of coordinates. The relation to other formalisms is established, and some technical problems at the interacting level are indicated.
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| 9. |
- Cederwall, Martin, 1961
(författare)
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Manifestly Lorentz covariant string theories in D=10 and D=18
- 1986
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Ingår i: Phys.Lett.B179 (1986) 66.
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Tidskriftsartikel (refereegranskat)abstract
- String models with both bosonic and fermionic variables in 10 and 18 space-time dimensions are examined at the non-interacting level. Both theories contain as open string ground states the N=2, D=10 non-chiral supergravity multiplet.
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| 10. |
- Cederwall, Martin, 1961
(författare)
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Suite for strings
- 1986
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)
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