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Bengtsson, Anders K. H.
Alternativa namn
Publikasjoner (10 av 19) Visa alla publikasjoner
Bengtsson, A. (2016). Investigations into light-front interactions for massless fields (I): Non-constructibility of higher spin quartic amlplitudes. Journal of High Energy Physics (JHEP), 12, 134, Article ID 134.
Åpne denne publikasjonen i ny fane eller vindu >>Investigations into light-front interactions for massless fields (I): Non-constructibility of higher spin quartic amlplitudes
2016 (engelsk)Inngår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 12, s. 134-, artikkel-id 134Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The dynamical commutators of the light-front Poincar{\'e} algebra yield first order differential equations in the $p^+$ momenta for the interaction vertex operators. The homogeneous solution to the equation for the quartic vertex is studied. Consequences as regards the constructibility assumption of quartic higher spin amplitudes from cubic amplitudes are discussed. The existence of quartic contact interactions unrelated to cubic interactions by Poincar{\'e} symmetry indicates that the higher spin S-matrix is not constructible. Thus quartic amplitude based no-go results derived by BCFW recursion for Minkowski higher spin massless fields may be circumvented.

Emneord
High spin symmetry, Higher spin gravity, Scattering amplitudes
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-11755 (URN)10.1007/JHEP12(2016)134 (DOI)000399774900001 ()2-s2.0-85008231230 (Scopus ID)
Tilgjengelig fra: 2017-01-11 Laget: 2017-01-11 Sist oppdatert: 2018-11-30bibliografisk kontrollert
Bengtsson, A. (2016). Quartic amplitudes for Minkowski higher spin. In: Lars Brink, Marc Henneaux, Mikhael A Vasiliev (Ed.), Higher Spin Gauge Theories: (pp. 353-370). Singapore: World Scientific
Åpne denne publikasjonen i ny fane eller vindu >>Quartic amplitudes for Minkowski higher spin
2016 (engelsk)Inngår i: Higher Spin Gauge Theories / [ed] Lars Brink, Marc Henneaux, Mikhael A Vasiliev, Singapore: World Scientific, 2016, s. 353-370Kapittel i bok, del av antologi (Annet vitenskapelig)
Abstract [en]

The old problem of finding general quartic interaction terms between fields of higher helicities on the light-front is discussed from the point of view of calculating the corresponding amplitudes directly from the cubic vertices using BCFW recursion. Amplitude based no-go results that has appeared in the literature are reviewed and discussed and it is pointed out how they may perhaps be circumvented.

sted, utgiver, år, opplag, sider
Singapore: World Scientific, 2016
Emneord
Higher spin theory, Scattering amplitudes
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-11757 (URN)978-981-3144-09-5 (ISBN)
Tilgjengelig fra: 2017-01-11 Laget: 2017-01-11 Sist oppdatert: 2017-01-11bibliografisk kontrollert
Atanasiu, D. & Bengtsson, A. (2015). Modern differential- och integralkalkyl (1ed.). Lund: Studentlitteratur AB
Åpne denne publikasjonen i ny fane eller vindu >>Modern differential- och integralkalkyl
2015 (svensk)Bok (Fagfellevurdert)
sted, utgiver, år, opplag, sider
Lund: Studentlitteratur AB, 2015. s. 418 Opplag: 1
HSV kategori
Forskningsprogram
Lärarutbildning och pedagogisk yrkesverksamhet
Identifikatorer
urn:nbn:se:hb:diva-8577 (URN)9789144110790 (ISBN)
Tilgjengelig fra: 2016-01-15 Laget: 2016-01-15 Sist oppdatert: 2025-01-08bibliografisk kontrollert
Bengtsson, A. (2014). A Riccati type PDE for light-front higher helicity vertices. Journal of High Energy Physics (JHEP), 9(105)
Åpne denne publikasjonen i ny fane eller vindu >>A Riccati type PDE for light-front higher helicity vertices
2014 (engelsk)Inngår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 9, nr 105Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

This paper is based on a curious observation about an equation related to the tracelessness constraints of higher spin gauge fields. A similar equation also occurs in the theory of continuous spin representations of the Poincaré group. Expressed in an oscillator basis for the higher spin fields, the equation becomes a non-linear partial differential operator of the Riccati type acting on the vertex functions. The consequences of the equation for the cubic vertex is investigated in the light-front formulation of higher spin theory. The vertex is fixed by the PDE up to a set of terms that can be considered as boundary data for the PDE. These terms can serve as off-shell quantum corrections. In order to set the present work in perspective, some comments and comparisons to recent research on higher spin interactions are made. A few particular cubic vertices are calculated explicitly and compared to similar results in the literature, in particular the interesting cases 2 ÿ 3 ÿ 3 and 3 ÿ 2 ÿ 2 involving spin 2 fields.

sted, utgiver, år, opplag, sider
Springer Berlin Heidelberg, 2014
Emneord
Higher Spin Gravity
HSV kategori
Forskningsprogram
Resursåtervinning
Identifikatorer
urn:nbn:se:hb:diva-2040 (URN)10.1007/JHEP09(2014)105 (DOI)2320/14660 (Lokal ID)2320/14660 (Arkivnummer)2320/14660 (OAI)
Tilgjengelig fra: 2015-11-13 Laget: 2015-11-13 Sist oppdatert: 2017-11-24bibliografisk kontrollert
Bengtsson, A. (2013). BRST theory for continuous spin. Journal of High Energy Physics (JHEP), 108(10)
Åpne denne publikasjonen i ny fane eller vindu >>BRST theory for continuous spin
2013 (engelsk)Inngår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 108, nr 10Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Some puzzling aspects of higher spin field theory in Minkowski space-time, such as the tracelessness constraints and the search for an underlying physical principle, are discussed. A connecting idea might be provided by the recently much researched continuous spin representations of the Poincaré group. The Wigner equations, treated as first class constraints, yields to a four-constraint BRST formulation. The resulting field theory, generalizing free higher spin field theory, is one among a set of higher spin theories that can be related to previous work on unconstrained formulations. In particular, it is conjectured that the unconstrained higher spin theory of Francia and Sagnotti is a limit of a continuous spin theory. Furthermore, a simple analysis of the constraint structure reveals a hint of a physical rationale behind the trace constraints.

sted, utgiver, år, opplag, sider
Springer, 2013
Emneord
Gauge Symmetry, BRST Symmetry
HSV kategori
Forskningsprogram
Resursåtervinning
Identifikatorer
urn:nbn:se:hb:diva-1788 (URN)10.1007/JHEP10(2013)108 (DOI)000325818500001 ()2320/13268 (Lokal ID)2320/13268 (Arkivnummer)2320/13268 (OAI)
Tilgjengelig fra: 2015-11-13 Laget: 2015-11-13 Sist oppdatert: 2017-11-24bibliografisk kontrollert
Bengtsson, A., Brink, L. & Kim, S.-S. (2013). Counterterms in gravity in the light-front formulation and a D = 2 conformal-like symmetry in gravity. Journal of High Energy Physics (JHEP), 118(3)
Åpne denne publikasjonen i ny fane eller vindu >>Counterterms in gravity in the light-front formulation and a D = 2 conformal-like symmetry in gravity
2013 (engelsk)Inngår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 118, nr 3Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

In this paper we discuss gravity in the light-front formulation (light-cone gauge) and show how possible counterterms arise. We find that Poincaré invariance is not enough to find the three-point counterterms uniquely. Higher-spin fields can intrude and mimic three-point higher derivative gravity terms. To select the correct term we have to use the remaining reparametrization invariance that exists after the gauge choice. We finally sketch how the corresponding programme for N = 8 Supergravity should work.

sted, utgiver, år, opplag, sider
Springer, 2013
Emneord
Models of Quantum Gravity, Conformal and W Symmetry
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-1787 (URN)10.1007/JHEP03(2013)118 (DOI)000317522400030 ()2320/13267 (Lokal ID)2320/13267 (Arkivnummer)2320/13267 (OAI)
Tilgjengelig fra: 2015-11-13 Laget: 2015-11-13 Sist oppdatert: 2017-11-24bibliografisk kontrollert
Bengtsson, A., Brink, L. & Kim, S.-S. (2013). Counterterms in Gravity in the Light-Front Formulation and a D=2 Conformal-like Summetry in Gravity. Journal of High Energy Physics (JHEP), 2013(3)
Åpne denne publikasjonen i ny fane eller vindu >>Counterterms in Gravity in the Light-Front Formulation and a D=2 Conformal-like Summetry in Gravity
2013 (engelsk)Inngår i: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 2013, nr 3Artikkel i tidsskrift (Annet vitenskapelig) Published
Abstract [en]

In this paper we discuss gravity in the light-front formulation (light-cone gauge) and show how possible counterterms arise. We find that Poincare invariance is not enough to find the three-point counterterms uniquely. Higher-spin fields can intrude and mimic three-point higher derivative gravity terms. To select the correct term we have to use the remaining reparametrization invariance that exists after the gauge choice. We finally sketch how the corresponding programme for N=8 Supergravity should work.

Emneord
IH Grundutbildningsanknyten forskning/Research related to first cycle programmes
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-1417 (URN)2320/11732 (Lokal ID)2320/11732 (Arkivnummer)2320/11732 (OAI)
Tilgjengelig fra: 2015-11-13 Laget: 2015-11-13 Sist oppdatert: 2018-01-16bibliografisk kontrollert
Bengtsson, A. (2013). Kan ingenjörsmatematik undervisas effektivt utgående från en humanistisk syn på matematiken?. In: : . Paper presented at 4:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar, Tekniska Högskolan vid Umeå universitet, 27 -28 november 2013.
Åpne denne publikasjonen i ny fane eller vindu >>Kan ingenjörsmatematik undervisas effektivt utgående från en humanistisk syn på matematiken?
2013 (svensk)Konferansepaper, Publicerat paper (Annet vitenskapelig)
Abstract [sv]

Matematikämnet i ungdomsskolan står i fokus för diskussioner, fortbildning och reformarbete sedan flera år. Iväntan på att förkunskaperna hos våra inkommande ingenjörsstudenter förbättras, vad kan vi som högskolelärare göra? Här argumenteras för ett angreppssätt som inte prövats i någon större utsträckning: Undervisa matematiken som en humanism och inte som ett hjälpämne till naturvetenskap och teknik; att ta de humanistiska aspekterna på matematiken som fundament för undervisningsmetoder och kursdesign. Detta kan skapa möjligheter att på allvar fokusera begreppsmässiga svårigheter samtidigt som exempel på matematikens tillämpningar inom teknik och samhälle kan moderniseras.

Emneord
Matematikundervisning, humanistisk matematik, liberal arts, Didactics, IH Grundutbildningsanknyten forskning/Research related to first cycle programmes, matematik och språk
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-7150 (URN)2320/13270 (Lokal ID)2320/13270 (Arkivnummer)2320/13270 (OAI)
Konferanse
4:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar, Tekniska Högskolan vid Umeå universitet, 27 -28 november 2013
Tilgjengelig fra: 2015-12-22 Laget: 2015-12-22 Sist oppdatert: 2017-02-12bibliografisk kontrollert
Bengtsson, A. (2012). Light-front higher-helicity interactions. In: Fortschritte der Physik. Special Issue: Proceedings of the XVIIthe European Workshop on String Theory 2011, Padua, Italy, 4-9 September 2011 (part 2): (pp. 1038-1043). Wiley
Åpne denne publikasjonen i ny fane eller vindu >>Light-front higher-helicity interactions
2012 (engelsk)Inngår i: Fortschritte der Physik. Special Issue: Proceedings of the XVIIthe European Workshop on String Theory 2011, Padua, Italy, 4-9 September 2011 (part 2), Wiley , 2012, s. 1038-1043Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

The reformulation, using Fock space vertex operators, of the original light-front cubic interaction terms for higher spin gauge fields is reviewed with comments on quantum higher spin gravity. The formalism is generalized to all orders in the interaction. The ensuing recursive equations for the higher order vertices, if they can be explicitly solved, will encode all interaction data into a denumerable set of rational functions of p+, the overall transverse momentum structure being fixed already at the kinematical level. A more thorough exposition can be found in the archive.

sted, utgiver, år, opplag, sider
Wiley, 2012
Emneord
Higher spin theory, higher spin gravity, light-front, cubic interactions, IH Grundutbildningsanknyten forskning/Research related to first cycle programmes
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-6869 (URN)10.1002/prop.201200035 (DOI)000308301500014 ()2320/11648 (Lokal ID)2320/11648 (Arkivnummer)2320/11648 (OAI)
Tilgjengelig fra: 2015-12-22 Laget: 2015-12-22 Sist oppdatert: 2017-02-09bibliografisk kontrollert
Bengtsson, A. (2012). Systematics of Higher-spin Light-front Interactions. Paper presented at XVII European Workshop on String Theory, Padua, 5-9 September 2011. arXiv
Åpne denne publikasjonen i ny fane eller vindu >>Systematics of Higher-spin Light-front Interactions
2012 (engelsk)Inngår i: arXivArtikkel i tidsskrift (Annet vitenskapelig) Published
Abstract [en]

The original cubic interaction terms for higher spin gauge fields in four dimensions and their reformulation using Fock space vertex operators is reviewed. As a new result, the complete list of all cubic vertex functions in D=4 is derived. It is observed, contrary to what would have been expected, that the non-linear dynamical Poincar\'e transformations do not restrict the cubic interactions beyond what is required by kinematics. The role of the SU(1,1) algebra of tracelessness constraints is clarified. It is shown that higher spin fields couple non-minimally to gravity at the cubic level in D=4 light-front dynamics. Based on a detailed analysis of the structure of the light-front Poincar\'e algebra, the formalism is then generalized to all orders in the interaction. The interacting theory, being a deformation of the free theory, takes the form of a strongly homotopy Lie algebra. It is conjectured that the ensuing recursive equations, if they can be explicitly solved, will encode all interaction data into a denumerable set of functions of p+, the overall transverse momentum structure being fixed already at the kinematical level.

Emneord
Higher spin field theory, Higher spin gravity, Light-front field theory, IH Grundutbildningsanknyten forskning/Research related to first cycle programmes
HSV kategori
Identifikatorer
urn:nbn:se:hb:diva-1445 (URN)2320/11802 (Lokal ID)2320/11802 (Arkivnummer)2320/11802 (OAI)
Konferanse
XVII European Workshop on String Theory, Padua, 5-9 September 2011
Merknad

Extended version of contribution to the XVII European Workshop on String Theory, Padua, 5-9 September 2011

Tilgjengelig fra: 2015-11-13 Laget: 2015-11-13 Sist oppdatert: 2018-02-17bibliografisk kontrollert
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