Complete Barrett-Crane model and its causal structure

نویسندگان

چکیده

The causal structure is a quintessential element of continuum spacetime physics and needs to be properly encoded in theory Lorentzian quantum gravity. Established spin foam (and tensorial group field (TGFT)) models mostly work with relatively special classes triangulations (e.g. built from spacelike tetrahedra only), obscuring the explicit implementation local at microscopic level. We overcome this limitation construct full-fledged model for geometry building blocks which include spacelike, lightlike timelike tetrahedra. realize within context Barrett-Crane TGFT model. Following an characterization amplitudes via methods integral geometry, ensuing clear identification structure, we analyze model's respect its (space)time-orientation properties provide also more detailed comparison framework dynamical (CDT).

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

On the causal Barrett–Crane model: measure, coupling constant, Wick rotation, symmetries and observables

We discuss various features and details of two versions of the Barrett–Crane spin foam model of quantum gravity, first of the Spin(4)-symmetric Riemannian model and second of the SL(2,C)-symmetric Lorentzian version in which all tetrahedra are space-like. Recently, Livine and Oriti proposed to introduce a causal structure into the Lorentzian Barrett–Crane model from which one can construct a pa...

متن کامل

Generalized Barrett-Crane Vertices and Invariants of Embedded Graphs

In [1] Barrett and Crane introduce a modification of the generalized CraneYetter state-sum (cf. [2]) based on the category of representations of Spin(4) ∼= SU(2)×SU(2), which provides a four-dimensional analogue of Regge and Ponzano’s [9] spin-network formulation of three-dimensional gravity. The key to the modification of the Crane-Yetter state-sum is the use of a different intertwiner between...

متن کامل

Dual variables and a connection picture for the Euclidean Barrett–Crane model

The partition function of the SO(4)or Spin(4)-symmetric Euclidean Barrett–Crane model can be understood as a sum over all quantized geometries of a given triangulation of a four-manifold. In the original formulation, the variables of the model are balanced representations of SO(4) which describe the quantized areas of the triangles. We present an exact duality transformation for the full quantu...

متن کامل

The Geometrization of Matter Proposal in the Barrett-Crane Model and Resolution of Cosmological Problems

The Barrett-Crane model [?] [?] is a constrained topological state sum model for quantum gravity. Recently [?] it was proposed that this model might incorporate matter and gauge interactions if the condition on triangulations to be manifolds were relaxed. That is, conical singularities would act as seeds of matter in the quantum geometry of the state sum. The purpose of this paper is to examine...

متن کامل

Positivity in Lorentzian Barrett-crane Models of Quantum Gravity

The Barrett-Crane models of Lorentzian quantum gravity are a family of spin foam models based on the Lorentz group. We show that for various choices of edge and face amplitudes, including the Perez-Rovelli normalization, the amplitude for every triangulated closed 4-manifold is a non-negative real number. Roughly speaking, this means that if one sums over triangulations, there is no interferenc...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

ژورنال

عنوان ژورنال: Physical review

سال: 2022

ISSN: ['0556-2813', '1538-4497', '1089-490X']

DOI: https://doi.org/10.1103/physrevd.106.066019