15,125 research outputs found
No radiative generation of Chern-Simons-like term in Lorentz-violating QED: dealing with IR divergences
The issue intensively claimed in the literature on the generation of a
CPT-odd and Lorentz violating Chern-Simons-like term by radiative corrections
owing to a CPT violating interaction -- the axial coupling of fermions with a
constant vector field b_\m -- is mistaken. The presence of massless gauge
field triggers IR divergences that might show up from the UV subtractions,
therefore, so as to deal with the (actual physical) IR divergences, the
Lowenstein-Zimmermann subtraction scheme, in the framework of BPHZL
renormalization method, has to be adopted. The proof on the non generation of
such a Chern-Simons-like term is done, independent of any kind of
regularization scheme, at all orders in perturbation theory.Comment: In honor of Prof. Manfred Schweda (1939-2017). Work presented at the
XXXVIII National Meeting on Particle Physics and Fields, September 18-22,
2017 - Passa Quatro - Minas Gerais - Brazil. Reference [46] correcte
Optimal path for a quantum teleportation protocol in entangled networks
Bellman's optimality principle has been of enormous importance in the
development of whole branches of applied mathematics, computer science, optimal
control theory, economics, decision making, and classical physics. Examples are
numerous: dynamic programming, Markov chains, stochastic dynamics, calculus of
variations, and the brachistochrone problem. Here we show that Bellman's
optimality principle is violated in a teleportation problem on a quantum
network. This implies that finding the optimal fidelity route for teleporting a
quantum state between two distant nodes on a quantum network with bi-partite
entanglement will be a tough problem and will require further investigation.Comment: 4 pages, 1 figure, RevTeX
An algebraic proof on the finiteness of Yang-Mills-Chern-Simons theory in D=3
A rigorous algebraic proof of the full finiteness in all orders of
perturbation theory is given for the Yang-Mills-Chern-Simons theory in a
general three-dimensional Riemannian manifold. We show the validity of a trace
identity, playing the role of a local form of the Callan-Symanzik equation, in
all loop orders, which yields the vanishing of the beta-functions associated to
the topological mass and gauge coupling constant as well as the anomalous
dimensions of the fields.Comment: 5 pages, revte
Algebraic Renormalization of Parity-Preserving QED_3 Coupled to Scalar Matter II: Broken Case
In this letter the algebraic renormalization method, which is independent of
any kind of regularization scheme, is presented for the parity-preserving QED_3
coupled to scalar matter in the broken regime, where the scalar assumes a
finite vacuum expectation value, . The model shows to be stable
under radiative corrections and anomaly free.Comment: 9 pages, latex, no figure
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