1,866 research outputs found

    On localization and position operators in Moebius-covariant theories

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    Some years ago it was shown that, in some cases, a notion of locality can arise from the group of symmetry enjoyed by the theory, thus in an intrinsic way. In particular, when Moebius covariance is present, it is possible to associate some particular transformations to the Tomita Takesaki modular operator and conjugation of a specific interval of an abstract circle. In this context we propose a way to define an operator representing the coordinate conjugated with the modular transformations. Remarkably this coordinate turns out to be compatible with the abstract notion of locality. Finally a concrete example concerning a quantum particle on a line is also given.Comment: 19 pages, UTM 705, version to appear in RM

    The paradigm of the area law and the structure of transversal and longitudinal lightfront degrees of freedom

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    It is shown that an algebraically defined holographic projection of a QFT onto the lightfront changes the local quantum properties in a very drastic way. The expected ubiquitous vacuum polarization characteristic of QFT is confined to the lightray (longitudinal) direction, whereas operators whose localization is transversely separated are completely free of vacuum correlations. This unexpected ''transverse return to QM'' combined with the rather universal nature of the strongly longitudinal correlated vacuum correlations (which turn out to be described by rather kinematical chiral theories) leads to a d-2 dimensional area structure of the d-1 dimensional lightfront theory. An additive transcription in terms of an appropriately defined entropy related to the vacuum restricted to the horizon is proposed and its model independent universality aspects which permit its interpretation as a quantum candidate for Bekenstein's area law are discussed. The transverse tensor product foliation structure of lightfront degrees of freedom is essential for the simplifying aspects of the algebraic lightcone holography. Key-words: Quantum field theory; Mathematical physics, Quantum gravityComment: 16 pages latex, identical to version published in JPA: Math. Gen. 35 (2002) 9165-918

    Anomalous Scale Dimensions from Timelike Braiding

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    Using the previously gained insight about the particle/field relation in conformal quantum field theories which required interactions to be related to the existence of particle-like states associated with fields of anomalous scaling dimensions, we set out to construct a classification theory for the spectra of anomalous dimensions. Starting from the old observations on conformal superselection sectors related to the anomalous dimensions via the phases which appear in the spectral decomposition of the center of the conformal covering group Z(SO(d,2)~),Z(\widetilde{SO(d,2)}), we explore the possibility of a timelike braiding structure consistent with the timelike ordering which refines and explains the central decomposition. We regard this as a preparatory step in a new construction attempt of interacting conformal quantum field theories in D=4 spacetime dimensions. Other ideas of constructions based on the AdS5AdS_{5}-CQFT4CQFT_{4} or the perturbative SYM approach in their relation to the present idea are briefly mentioned.Comment: completely revised, updated and shortened replacement, 24 pages tcilatex, 3 latexcad figure

    Jorge A. Swieca's contributions to quantum field theory in the 60s and 70s and their relevance in present research

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    After revisiting some high points of particle physics and QFT of the two decades from 1960 to 1980, I comment on the work by Jorge Andre Swieca. I explain how it fits into the quantum field theory during these two decades and draw attention to its relevance to the ongoing particle physics research. A particular aim of this article is to direct thr readers mindfulness to the relevance of what at the time of Swieca was called "the Schwinger Higgs screening mechanism". which, together with recent ideas which generalize the concept of gauge theories, has all the ingredients to revolutionize the issue of gauge theories and the standard model.Comment: 49 pages, expansion and actualization of text, improvement of formulations and addition of many references to be published in EPJH - Historical Perspectives on Contemporary Physic

    Modular Structure and Duality in Conformal Quantum Field Theory

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    Making use of a recent result of Borchers, an algebraic version of the Bisognano-Wichmann theorem is given for conformal quantum field theories, i.e. the Tomita-Takesaki modular group associated with the von Neumann algebra of a wedge region and the vacuum vector concides with the evolution given by the rescaled pure Lorentz transformations preserving the wedge. A similar geometric description is valid for the algebras associated with double cones. Moreover essential duality holds on the Minkowski space MM, and Haag duality for double cones holds provided the net of local algebras is extended to a pre-cosheaf on the superworld M~\tilde M, i.e. the universal covering of the Dirac-Weyl compactification of MM. As a consequence a PCT symmetry exists for any algebraic conformal field theory in even space-time dimension. Analogous results hold for a Poincar\'e covariant theory provided the modular groups corresponding to wedge algebras have the expected geometrical meaning and the split property is satisfied. In particular the Poincar\'e representation is unique in this case.Comment: 23 pages, plain TeX, TVM26-12-199

    Architectures of domestication : on emplacing human-animal relations in the North

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    Acknowledgements. This fieldwork and discussions which led to this article was sponsored by ERC Advanced Grant 295458 Arctic Domus and ESRC grant ES‐MO110548‐1 JPI Climate Humanor. We would like to thank Rob Losey, Bente Sundsvold, and Konstantin Klokov for their comments on the manuscript. We would also like to thank that particularly engaging and constructive comments from three anonymous reviewers.Peer reviewedPublisher PD

    An alternative to the gauge theoretic setting

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    The standard formulation of gauge theories results from the Lagrangian (functional integral) quantization of classical gauge theories. A more intrinsic qunantum theoretical access in the spirit of Wigner's representation theory shows that there is a fundamental clash between the pointlike localization of zero mass (vector, tensor) potentials and the Hilbert space (positivity, unitarity) structure of QT. The quantization approach has no other way than to stay with pointlike localization and sacrifice the Hilbert space whereas the approach build on the intrinsic quantum concept of modular localization keeps the Hilbert space and trades the conflict creating pointlike generation with the tightest consistent localization:: semiinfinite spacelike string localization. Whereas these potentials in the presence of interactions stay quite close to associated pointlike field strength, the interacting matter fields to which they are coupled bear the brunt of the nonlocal aspect in that they are string.generated in a way which cannot be undone by any differentiation. The new stringlike approach to gauge theory also revives the idea of a Schwinger-Higgs screening mechanism as a deeper and less metaphoric description of the Higgs spontaneous symmetry breaking and its accompanying tale about "God's particle" and its mass generation for all other particles.Comment: 26 page

    The genetic diversity, relationships, and potential for biological control of the lobate lac scale, Paratachardina pseudolobata Kondo & Gullan (Hemiptera: Coccoidea: Kerriidae)

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    The lobate lac scale Paratachardina pseudolobata Kondo & Gullan (Kerriidae) is a polyphagous pest of woody plants in Florida (U.S.A.) the Bahamas, Christmas Island (Australia) and it has been reported from Cuba. Its recent appearance as a pest in these places indicates that this scale is introduced; however, its native range is unknown. Until 2006, this pest species was identified mistakenly as Paratachardina lobata (Chamberlin) [now P. silvestri (Mahdihassan)], which is native to India and Sri Lanka. Quarantine laboratory acceptance trials with Indian P. silvestri parasitoids indicated a strong immune response from P. pseudolobata. Gregarious development of encyrtid wasps was the only observed parasitism, but parasitization levels were below 3%. Identification of the native range of P. pseudolobata would facilitate the search for natural enemies better adapted to the scale. Sequence data from the D2–D3 region of the nuclear large subunit ribosomal RNA gene (LSU rRNA, 28S) and the mitochondrial gene cytochrome oxidase I (COI) distinguished P. pseudolobata from the morphologically similar species P. silvestri and P. mahdihassani Kondo & Gullan, and showed P. pseudolobata to be more closely related to these Indotropical species than to an Australian species of Paratachardina Balachowsky. Paratachardina pseudolobata was genetically uniform throughout its exotic range, consistent with a single geographic origin, although lack of variation in these genes is not unusual for scale insects. Molecular identification of morphologically similar Paratachardina species was possible using the D2–D3 region of 28S, despite its length variation, suggesting that this gene region might be suitable as a non-COI barcoding gene for scale insects
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