We consider a theory of scalar and spinor fields, interacting through Yukawa and 4 interactions, with Lorentz-violating operators included in the Lagrangian. We compute the leading quantum corrections in this theory. The renormalizability of the theory is explicitly shown up to one-loop order. In the pure scalar sector, the calculations can be generalized to higher orders and to include finite terms, because the theory can be solved in terms of its Lorentz-invariant version.

A time-varying fine structure constant ðtÞ could give rise to Lorentz-and CPT-violating changes to the vacuum polarization, which would affect photon propagation. Such changes to the effective action can violate gauge invariance, but they are otherwise permitted. However, in the minimal theory of varying , no such terms are generated at lowest order. At second order, vacuum polarization can generate an instability-a Lorentz-violating analogue of a negative photon mass squared Àm 2 / ð _ 2 Þ 2 logðà 2 Þ, where à is the cutoff for the low-energy effective theory.Two exotic forms of physics beyond the standard model that have recently gotten a lot of attention are Lorentz symmetry violations [1] and time-dependent fundamental constants. If these two phenomena exist, they are likely to be closely related. For example, if the fine structure constant ¼ e 2 4 is actually a function of time ðtÞ, there is naturally a preferred spacetime direction, @ , which violates boost invariance. We shall investigate this potential connection, which may also be related to violations of electrodynamical gauge invariance.The most common theory with varying constants that has been studied is one with a time-dependent . Other possibilities have included changes in the quantum chromodynamics scale à QCD and therefore the electron-proton mass ratio. However, these possibilities are usually approached phenomenalistically, without reference to a full underlying quantum field theory. Lorentz violation has been treated somewhat differently in recent years. Although there is a long history of searches for deviations from special relativity-also frequently handled in purely phenomenalistic fashion-the standard approach now is to use effective field theory. The effective field theory containing all possible local, Lorentz-violating operators built from standard model fields is called the standard model extension (SME) [2]. The SME Lagrange density contains new operators, involving tensor objects constructed from quantum fields, contracted with constant background tensors. An example of such an operator is Àa " c c . For parameterizing the results of experimental tests, a restricted subset of the theory, the minimal SME, is typically used. The minimal SME contains only operators that are gauge invariant and power counting renormalizable.Lorentz violation and varying constants have both been tightly constrained experimentally, and many of the most stringent tests are in quantum electrodynamics (QED). In most cases, it is conventional to consider only the leading order effects of Lorentz violation or a varying ; since _ must be small, Oð _ 2 Þ terms may be of negligible importance. In this paper, we shall begin by following this convention; however, the higher order terms are interesting when they can produce qualitatively different effects than those possible at leading order. For this reason, after discussing Oð _ Þ radiative corrections, we shall consider additional effects that are Oð _ 2 Þ and Oð € Þ. Measurements of _ may be made in a number of...

We consider the thermodynamic effects of an electrically charged impurity immersed in a two-dimensional two-component plasma, composed by particles with charges ±e, at temperature T , at coupling Γ = e 2 /(k B T ) = 2, confined in a large disk of radius R. Particularly, we focus on the analysis of the charge density, the correlation functions, and the grand potential. Our analytical results show how the charges are redistributed in the circular geometry considered here. When we consider a positively charged impurity, the negative ions accumulate close to the impurity leaving an excess of positive charge that accumulates at the boundary of the disk. Due to the symmetry under charge exchange, the opposite effect takes place when we place a negative impurity. Both the cases in which the impurity charge is an integer multiple of the particle charges in the plasma, ±e, and a fraction of them are considered; both situations require a slightly different mathematical treatments, showing the effect of the quantization of plasma charges. The bulk and tension effects in the plasma described by the grand potential are not modified by the introduction of the charged particle. Besides the effects due to the collapse coming from the attraction between oppositely charged ions, an additional topological term appears in the grand potential, proportional to −n 2 ln(mR), with n the dimensionless charge of the particle. This term modifies the central charge of the system, from c = 1 to c = 1 − 6n 2 , when considered in the context of conformal field theories.

The light curve of a type Ia supernova decays at a rate set by the β-decay lifetimes of the 56 Ni and 56 Co produced in the explosion. This makes such a light curve sensitive

A time-varying fine structure constant α(t) could give rise to Lorentz-and CP Tviolating changes to the vacuum polarization, which would affect photon propagation. Such changes to the effective action can violate gauge invariance, but they are otherwise permitted. However, in the minimal theory of varying α, no such terms are generated at lowest order. At second order, vacuum polarization can generate an instability-a Lorentz-violating analogue of a negative photon mass squared −m 2 γ ∝ α α 2α 2 log(Λ 2 ), where Λ is the cutoff for the low-energy effective theory.