scholarly journals TORSION, CHERN–SIMONS TERM AND DIFFEOMORPHISM INVARIANCE

2011 ◽  
Vol 26 (06) ◽  
pp. 415-421 ◽  
Author(s):  
PRASANTA MAHATO ◽  
PARTHA BHATTACHARYA

In the torsion ⊗ curvature approach of gravity Chern–Simons modification has been considered here. It has been found that Chern–Simons contribution to the Bianchi identity cancels from that of the scalar field part. But "homogeneity and isotropy" consideration of present day cosmology is a consequence of the "strong equivalence principle" and vice versa.

1993 ◽  
Vol 08 (04) ◽  
pp. 723-752 ◽  
Author(s):  
A.P. BALACHANDRAN ◽  
P. TEOTONIO-SOBRINHO

It is known that the 3D Chern–Simons interaction describes the scaling limit of a quantum Hall system and predicts edge currents in a sample with boundary, the currents generating a chiral U(1) Kac-Moody algebra. It is no doubt also recognized that, in a somewhat similar way, the 4D BF interaction (with B a two-form, dB the dual *j of the electromagnetic current, and F the electromagnetic field form) describes the scaling limit of a superconductor. We show in this paper that there are edge excitations in this model as well for manifolds with boundaries. They are the modes of a scalar field with invariance under the group of diffeomorphisms (diffeos) of the bounding spatial two-manifold. Not all diffeos of this group seem implementable by operators in quantum theory, the implementable group being a subgroup of volume-preserving diffeos. The BF system in this manner can lead to the w1+∞ algebra and its variants. Lagrangians for fields on the bounding manifold which account for the edge observables on quantization are also presented. They are the analogs of the (1+1)-dimensional massless scalar field Lagrangian describing the edge modes of an Abelian Chern-Simons theory with a disk as the spatial manifold. We argue that the addition of “Maxwell” terms constructed from F∧*F and dB∧*dB does not affect the edge states, and that the augmented Lagrangian has an infinite number of conserved charges—the aforementioned scalar field modes—localized at the edges. This Lagrangian is known to describe London equations and a massive vector field. A (3+1)-dimensional generalization of the Hall effect involving vortices coupled to B is also proposed.


2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Shao-Jun Zhang

AbstractWe study massive scalar field perturbation on Kerr black holes in dynamical Chern–Simons gravity by performing a $$(2+1)$$ ( 2 + 1 ) -dimensional simulation. Object pictures of the wave dynamics in time domain are obtained. The tachyonic instability is found to always occur for any nonzero black hole spin and any scalar field mass as long as the coupling constant exceeds a critical value. The presence of the mass term suppresses or even quench the instability. The quantitative dependence of the onset of the tachyonic instability on the coupling constant, the scalar field mass and the black hole spin is given numerically.


1992 ◽  
Vol 70 (5) ◽  
pp. 301-304 ◽  
Author(s):  
D. G. C. McKeon

We investigate a three-dimensional gauge theory modeled on Chern–Simons theory. The Lagrangian is most compactly written in terms of a two-index tensor that can be decomposed into fields with spins zero, one, and two. These all mix under the gauge transformation. The background-field method of quantization is used in conjunction with operator regularization to compute the real part of the two-point function for the scalar field.


2017 ◽  
Vol 32 (13) ◽  
pp. 1750064 ◽  
Author(s):  
Subir Mukhopadhyay ◽  
Chandrima Paul

We study SU(2)[Formula: see text]×[Formula: see text]U(1) gauge theory with Chern–Simons term, coupled to scalar field in adjoint, in a probe approximation by ignoring back reaction on metric. Considering a simple ansatz for non-Abelian gauge field with helical structure, we find it admits s-wave and p-wave phases along with their coexistence. We study free energies for different phases along with those for p-wave phases for different values of pitch and frequency dependence of optical conductivities below critical temperature.


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