scholarly journals Energy-momentum tensor for scalar fields coupled to the dilaton in two dimensions

1999 ◽  
Vol 59 (6) ◽  
Author(s):  
Fernando C. Lombardo ◽  
Francisco D. Mazzitelli ◽  
Jorge G. Russo
Keyword(s):  
Energy Momentum Tensor ◽  
Scalar Fields ◽  
Momentum Tensor ◽  
Two Dimensions

REMARKS ON THE MODEL WITH LOCAL U(1)V×U(1)A SYMMETRY IN TWO DIMENSIONS

1991 ◽  
Vol 06 (14) ◽  
pp. 1291-1298 ◽  
Author(s):  
YOSHIYUKI WATABIKI
Keyword(s):  
Energy Momentum Tensor ◽  
Central Charge ◽  
Axial Vector ◽  
Local Symmetry ◽  
Momentum Tensor ◽  
Two Dimensions ◽  
Global Symmetry ◽  
Supersymmetric Extension ◽  
Commutator Algebra ◽  
Local Vector

We investigate a 2-dimensional model which possesses a local vector U (1)V and axial vector U (1)A symmetry. We obtain a general form of Lagrangian which possesses this local symmetry. We also investigate the global symmetry aspects of the model. The commutator algebra of the energy-momentum tensor and the currents is derived, and the central charge of the model is calculated. Supersymmetric extension of the model is also studied.

PERTURBATION THEORY IN THE WESS–ZUMINO–NOVIKOV–WITTEN MODEL

1992 ◽  
Vol 07 (04) ◽  
pp. 795-841 ◽  
Author(s):  
H. LEUTWYLER ◽  
M. SHIFMAN
Keyword(s):  
Perturbation Theory ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Two Dimensions ◽  
Perturbative Approach ◽  
Generating Functional ◽  
Wznw Model

The perturbation theory of the WZNW model in two dimensions is investigated. We obtain closed expressions for the generating functional of the chiral currents and of the energy–momentum tensor, valid to all orders in 1/k where k is the integer parameter of the model. It is demonstrated how the relations of the Kač–Moody and Virasoro algebras emerge within the perturbative approach.

scholarly journals PALATINI FORMULATION OF MODIFIED GRAVITY WITH A NON-MINIMAL CURVATURE-MATTER COUPLING

2011 ◽  
Vol 26 (20) ◽  
pp. 1467-1480 ◽  
Author(s):  
TIBERIU HARKO ◽  
TOMI S. KOIVISTO ◽  
FRANCISCO S. N. LOBO
Keyword(s):  
Energy Momentum Tensor ◽  
Equations Of Motion ◽  
Scalar Fields ◽  
Momentum Tensor ◽  
Nonlinear Dependence ◽  
Modified Theories Of Gravity ◽  
Field Equations ◽  
Test Particles ◽  
Theories Of Gravity ◽  
Minimal Curvature

We derive the field equations and the equations of motion for scalar fields and massive test particles in modified theories of gravity with an arbitrary coupling between geometry and matter by using the Palatini formalism. We show that the independent connection can be expressed as the Levi–Cività connection of an auxiliary, matter Lagrangian dependent metric, which is related with the physical metric by means of a conformal transformation. Similarly to the metric case, the field equations impose the nonconservation of the energy–momentum tensor. We derive the explicit form of the equations of motion for massive test particles in the case of a perfect fluid, and the expression of the extra-force is obtained in terms of the matter-geometry coupling functions and of their derivatives. Generally, the motion is non-geodesic, and the extra force is orthogonal to the four-velocity. It is pointed out here that the force is of a different nature than in the metric formalism. We also consider the implications of a nonlinear dependence of the action upon the matter Lagrangian.

Unified DE–DM with diffusive interactions scenario from scalar fields

2017 ◽  
Vol 26 (12) ◽  
pp. 1743021 ◽  
Author(s):  
David Benisty ◽  
E. I. Guendelman
Keyword(s):  
Dark Matter ◽  
Fixed Point ◽  
Energy Momentum Tensor ◽  
Scalar Fields ◽  
Equation Of Motion ◽  
Momentum Conservation ◽  
Momentum Tensor ◽  
Gravitational Energy ◽  
Spacetime Theory ◽  
Energy Momentum Conservation

Generalized models of unified dark matter (DM) and dark energy (DE) in the context of Two Measure Theories and of dynamical spacetime theories are obtained. In Two Measure Theories, one uses metric independent volume elements and this allows to construct unified DM and DE, where the cosmological constant appears as an integration constant associated to the equation of motion of the measure fields. The dynamical spacetime theories generalize the Two Measure Theories by introducing a vector field whose equation of motion guarantees the conservation of a certain energy–momentum tensor, which may be related, but in general is not the same as the gravitational energy–momentum tensor. By considering the dynamical space field appearing in another part of the action (apart from the coupling to the energy–momentum tensor), we can obtain noncovariant energy–momentum conservation. Then, the dynamical spacetime theory becomes a theory of diffusive unified DE and DM. The nonconserved energy–momentum tensors lead at the end to a formulation of interacting DE–DM models in the form of a diffusive type interacting unified DE and DM scenario. We solved analytically the theories for asymptotic solution, and we show that the [Formula: see text]CDM is a fixed point of these theories at large times.

scholarly journals QUANTUM EVOLUTION OF SCALAR FIELDS IN ROBERTSON-WALKER SPACE-TIME

1996 ◽  
Vol 11 (21) ◽  
pp. 3957-3971 ◽  
Author(s):  
H.C. REIS ◽  
O.J.P. ÉBOLI
Keyword(s):  
Field Theory ◽  
Energy Momentum Tensor ◽  
Gaussian Approximation ◽  
Scalar Fields ◽  
Momentum Tensor ◽  
Space Time ◽  
Quantum Evolution ◽  
Coupling Constant ◽  
Pure States ◽  
Schrödinger Picture

We study the λɸ4 field theory in a flat Robertson-Walker space-time using the functional Schrödinger picture. We introduce a simple Gaussian approximation to analyze the time evolution of pure states and we establish the renormalizability of the approximation. We also show that the energy–momentum tensor in this approximation is finite once we consider the usual mass and coupling constant renormalizations.

scholarly journals ENERGY-MOMENTUM TENSOR IMPROVEMENTS IN TWO DIMENSIONS

1996 ◽  
Vol 10 (13n14) ◽  
pp. 1499-1506 ◽  
Author(s):  
S. DESER ◽  
R. JACKIW
Keyword(s):  
Scalar Field ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Two Dimensions ◽  
Conformal Anomaly ◽  
Gravitational Coupling ◽  
Two Dimensional

We discuss some aspects of the two-dimensional scalar field, considering particularly the action for the conformal anomaly as an “improved” gravitational coupling, and the possibility of introducing a dual coupling, which provides a “chiral” energy-momentum tensor improvement.

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