The 1–loop effective Lagrangian for a massive scalar field on an arbitrary causality violating spacetime is calculated using the methods of Euclidean quantum field theory in curved spacetime. Fields of spin 12 , spin 1 and twisted field configurations are also considered. In general, we find that the Lagrangian diverges to minus infinity at each of the nth polarised hypersurfaces of the spaceti...

A passive scalar field was studied under the action of pumping, diffusion and advection by a 2D smooth flow with Lagrangian chaos. We present theoretical arguments showing that the scalar statistics are not conformally invariant and formulate a new effective semi-analytic algorithm to model scalar turbulence. We then carry out massive numerics of scalar turbulence, focusing on nodal lines. The ...

We study the propagation of gravitons within 5-D supersymmetric braneworld models with a bulk scalar field. The setup considered here consists of a 5-D bulk spacetime bounded by two 4-D branes localized at the fixed points of an S/Z2 orbifold. There is a scalar field φ in the bulk which, provided a superpotential W (φ), determines the warped geometry of the 5-D spacetime. This type of scenario ...

We investigate the structure of equations of motion and lagrangian constraints in the most general theory of massive spin 2 field interacting with external gravitational field. We demonstrate how consistency with the flat spacetime limit can be achieved if the external gravity fulfills vacuum Einstein equations with arbitrary cosmological constant and show that in this case there exists one-par...

In this note we comment recent paper by A.V. Minkevich 'Regular inflationary cosmology and gauge theories of gravity' on the 'bouncing' character of flat-type inflationary cosmolog-ical models within gauge theories of gravity. Recently [1] it was argued that inflationary cosmological solutions in the case of flat models within the framework of gauge theories of gravity have 'bouncing' character...

A discussion of the field content of quadratic higher-derivative gravitation is presented, together with a new example of a massless spin-two field consistently coupled to gravity. The full quadratic gravity theory is shown to be equivalent to a canonical secondorder theory of a massive scalar field, a massive spin-two symmetric tensor field and gravity. The conditions showing that the tensor f...

We consider a model with global Abelian chiral symmetry of two massless fermion fields interacting with a complex massive scalar field. We argue that the Schwinger–Dyson equations for the fermion and boson propagators admit ultraviolet-finite chiral-symmetry-breaking solutions provided the Yukawa couplings are large enough. The fermions acquire masses and the elementary excitations of the compl...

Physical arguments related with the existence of black holes solutions having a nontrapping interior are discussed. Massive scalar fields interacting with gravity are considered. Interior asymptotic solutions showing a scalar field approaching a constant value at the horizon are given. It is argued that the coupled Einstein-Klein-Gordon equations can be satisfied in the sense of the generalized...