| 1. |
- Adawi, Tom, 1970, et al.
(författare)
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Superembeddings, nonlinear supersymmetry and five-branes
- 1997
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Ingår i: Int.J.Mod.Phys.A13:4691-4716,1998.
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Tidskriftsartikel (refereegranskat)abstract
- We examine general properties of superembeddings, i.e., embeddings of supermanifolds into supermanifolds. The connection between an embedding procedure and the method of non-linearly realised supersymmetry is clarified, and we demonstrate how the latter arises as a special case of the former. As an illustration, the super-5-brane in 7 dimensions, containing a self-dual 3-form world-volume field strength, is formulated in both languages, and provides an example of a model where the embedding condition does not suffice to put the theory on-shell.
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| 2. |
- Cederwall, Martin, 1961, et al.
(författare)
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Finite tensor deformations of supergravity solitons
- 1998
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Ingår i: J. High Energy Phys. 9902:003,1999.
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Tidskriftsartikel (refereegranskat)abstract
- We consider brane solutions where the tensor degrees of freedom are excited. Explicit solutions to the full non-linear supergravity equations of motion are given for the M5 and D3 branes, corresponding to finite selfdual tensor or Born-Infeld field strengths. The solutions are BPS-saturated and half-supersymmetric. The resulting metric space-times are analysed.
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| 3. |
- Adawi, Tom, 1970, et al.
(författare)
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Goldstone tensor modes
- 1998
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Ingår i: J. High Energy Phys. 9902:001,1999.
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Tidskriftsartikel (refereegranskat)abstract
- In the context of brane solutions of supergravity, we discuss a general method to introduce collective modes of any spin by exploiting a particular way of breaking symmetries. The method is applied to the D3, M2 and M5 branes and we derive explicit expressions for how the zero-modes enter the target space fields, verify normalisability in the transverse directions and derive the corresponding field equations on the brane. In particular, the method provides a clear understanding of scalar, spinor, and rank r tensorial Goldstone modes, chiral as well as non-chiral, and how they arise from the gravity, Rarita-Schwinger, and rank r+1 Kalb-Ramond tensor gauge fields, respectively. Some additional observations concerning the chiral tensor modes on the M5 brane are discussed.
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| 4. |
- Baggioli, Matteo, et al.
(författare)
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Collective modes of polarizable holographic media in magnetic fields
- 2021
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; 2021:6
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Tidskriftsartikel (refereegranskat)abstract
- We consider a neutral holographic plasma with dynamical electromagnetic interactions in a finite external magnetic field. The Coulomb interactions are introduced via mixed boundary conditions for the Maxwell gauge field. The collective modes at finite wave-vector are analyzed in detail and compared to the magneto-hydrodynamics results valid only at small magnetic fields. Surprisingly, at large magnetic field, we observe the appearance of two plasmon-like modes whose corresponding effective plasma frequency grows with the magnetic field and is not supported by any background charge density. Finally, we identify a mode collision which allows us to study the radius of convergence of the linearized hydrodynamics expansion as a function of the external magnetic field. We find that the radius of convergence in momentum space, related to the diffusive transverse electromagnetic mode, increases quadratically with the strength of the magnetic field.
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| 5. |
- Baggioli, Matteo, et al.
(författare)
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Holographic plasmon relaxation with and without broken translations
- 2019
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Ingår i: Journal of High Energy Physics (JHEP). - : SPRINGER. - 1126-6708 .- 1029-8479. ; :9
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Tidskriftsartikel (refereegranskat)abstract
- We study the dynamics and the relaxation of bulk plasmons in strongly coupled and quantum critical systems using the holographic framework. We analyze the dispersion relation of the plasmonic modes in detail for an illustrative class of holographic bottom-up models. Comparing to a simple hydrodynamic formula, we entangle the complicated interplay between the three least damped modes and shed light on the underlying physical processes. Such as the dependence of the plasma frequency and the effective relaxation time in terms of the electromagnetic coupling, the charge and the temperature of the system. Introducing momentum dissipation, we then identify its additional contribution to the damping. Finally, we consider the spontaneous symmetry breaking (SSB) of translational invariance. Upon dialing the strength of the SSB, we observe an increase of the longitudinal sound speed controlled by the elastic moduli and a decrease in the plasma frequency of the gapped plasmon. We comment on the condensed matter interpretation of this mechanism.
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| 6. |
- Baggioli, Matteo, et al.
(författare)
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Transverse collective modes in interacting holographic plasmas
- 2020
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; 2020:4
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Tidskriftsartikel (refereegranskat)abstract
- We study in detail the transverse collective modes of simple holographic models in presence of electromagnetic Coulomb interactions. We render the Maxwell gauge field dynamical via mixed boundary conditions, corresponding to a double trace deformation in the boundary field theory. We consider three different situations: (i) a holographic plasma with conserved momentum, (ii) a holographic (dirty) plasma with finite momentum relaxation and (iii) a holographic viscoelastic plasma with propagating transverse phonons. We observe two interesting new features induced by the Coulomb interactions: a mode repulsion between the shear mode and the photon mode at finite momentum relaxation, and a propagation-to-diffusion crossover of the transverse collective modes induced by the finite electromagnetic interactions. Finally, at large charge density, our results are in agreement with the transverse collective mode spectrum of a charged Fermi liquid for strong interaction between quasi-particles, but with an important difference: the gapped photon mode is damped even at zero momentum. This property, usually referred to as anomalous attenuation, is produced by the interaction with a quantum critical continuum of states and might be experimentally observable in strongly correlated materials close to quantum criticality, e.g. in strange metals.
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| 7. |
- Beck, S., et al.
(författare)
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All Killing superalgebras for warped AdS backgrounds
- 2018
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Ingår i: Journal of High Energy Physics. - 1029-8479 .- 1126-6708. ; 2018:12
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Tidskriftsartikel (refereegranskat)abstract
- We present all the symmetry superalgebras ? of all warped AdSk ×wMd − k, k > 2, flux backgrounds in d = 10, 11 dimensions preserving any number of supersymmetries. First we give the conditions for ? to decompose into a direct sum of the isometry algebra of AdSk and that of the internal space Md − k. Assuming this decomposition, we identify all symmetry superalgebras of AdS3 backgrounds by showing that the isometry groups of internal spaces act transitively on spheres. We demonstrate that in type II and d = 11 theories the AdS3 symmetry superalgebras may not be simple and also present all symmetry superalgebras of heterotic AdS3 backgrounds. Furthermore, we explicitly give the symmetry superalgebras of AdSk, k > 3, backgrounds and prove that they are all classical.
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| 8. |
- Benjaminsson, Daniel, et al.
(författare)
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Advanced study techniques for university students
- 2023
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Ingår i: Proceedings Chalmers Conference on Teaching and Learning 2023. - 9789188041548 ; , s. 61-67
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Konferensbidrag (refereegranskat)abstract
- The students starting at the Engineering Physics and Engineering Mathematics educations at Chalmers face challenges in terms of greatly increased workload and complexity of the subject matter compared to their previous education. Based on the experiences from teaching an introductory course in mechanics for nearly ten years (Ulf), the lack of efficient study techniques for a large number of students was identified. We have this year therefore offered the students a course in advanced study techniques (Daniel) tailored for university students, and also for their specific educations. We will here briefly describe the contents of the course and the preliminary impact on student learning.
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| 9. |
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| 10. |
- Berman, David S., et al.
(författare)
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Holographic Noncommutativity
- 2000
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Ingår i: J. High Energy Phys. ; 05, s. 002-
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Tidskriftsartikel (refereegranskat)
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