Test of Lorentz invariance using optical cavities

This paper indroduces the precision test of Lorentz invariance using ultra-stable and low-loss optical cavities. The effective-field theory widely adopted in the analysis of experimental data has been reviewed. The sensitivity of the cavity resonant frequency to the Lorentz-violating tensor field is discussed in detail. In addition, the polarization of the optical field has been added to the model, and our analysis shows that the frequency shift due to Lorentz violation is not sensitive to the polarization of the optical field.      

Constraining Lorentz invariance violation from the continuous spectra of short gamma-ray bursts

In some quantum gravity theories, a foamy structure of space-time may lead to Lorentz invariance violation(LIV). As the most energetic explosions in the Universe, gamma-ray bursts(GRBs) provide an effect way to probe quantum gravity effects. In this paper, we use the continuous spectra of 20 short GRBs detected by the Swift satellite to give a conservative lower limit of quantum gravity energy scale MQG. Due to the LIV effect, photons with different energy have different velocities. This will lead to the delayed arrival of high energy photons relative to low energy ones. Based on the fact that the LIV-induced time delay cannot be longer than the duration of a GRB,we present the most conservative estimate of the quantum gravity energy scales from 20 short GRBs. The strictest constraint, M_(QG) 5.05 × 10~(14) GeV in the linearly corrected case, is from GRB 140622 A. Our constraint on MQG,although not as tight as previous results, is the safest and most reliable so far.     

Study of Lorentz violation in INTEGRAL gamma-ray bursts

We search for possible time lags caused by quantum gravitational effects using gamma-ray bursts (GRBs) detected by INTEGRAL. The advantage of this satellite is that we have at our disposal the energy and arrival time of every detected single photon, which enhances the precision of the time resolution. We present a new method for seeking time lags in unbinned data using a maximum likelihood method and support our conclusions with Monte Carlo simulations. The analysis establishes a conservative lower bound on the Lorentz invariance violation scale, which is several orders of magnitude below the Planck mass, whose value may however increase if better statistics of GRBs were available. Furthermore, we disagree with previous studies in which a non-monotonic function of the redshift was used to perform a linear fit.     

Lorentz violation constrained by triplicity of lepton families and neutrino oscillations

In this paper we postulate an algebraic model to relate the triplet characteristic of lepton families to Lorentz violation. Inspired by the two-to-one mapping between the group SL(2, C) and the Lorentz group via the Pauli grading (the elements of SL(2, C) expressed by direct sum of unit matrix and generators of SU (2) group), we grade the SL(3, C) group with the generators of SU(3), i. e. the Gell-Mann matrices, then express the SU(3) group in terms of three SU(2) subgroups, each of which stands for a lepton species and is mapped into the proper Lorentz group as in the case of the group SL(2,C). If the mapping from group SL(3,C) to the Lorentz group is constructed by choosing one SU(2) subgroup as basis, then the other two subgroups display their impact only by one more additional generator to that of the original Lorentz group. Applying the mapping result to the Dirac equation, it is found that only when the kinetic vertex γμξμ is extended to encompass γμξμ can the Dirac-equation-form be conserved. The generalized vertex is useful in producing neutrino oscillations and mass differences.     

Lorentz violation constrained by triplicity of lepton families and neutrino oscillations

In this paper we postulate an algebraic model to relate the triplet characteristic of lepton families to Lorentz violation. Inspired by the two-to-one mapping between the group SL（2, C） and the Lorentz group via the Pauli grading （the elements of SL（2, C） expressed by direct sum of unit matrix and generators of SU（2） group）, we grade the SL（3,C） group with the generators of SU（3）, i. e. the Gell-Mann matrices, then express the SU（3） group in terms of three SU（2） subgroups, each of which stands for a lepton species and is mapped into the proper Lorentz group as in the case of the group SL（2,C）. If the mapping from group SL（3,C） to the Lorentz group is constructed by choosing one SU（2） subgroup as basis, then the other two subgroups display their impact only by one more additional generator to that of the original Lorentz group. Applying the mapping result to the Dirac equation, it is found that only when the kinetic vertex -γμθ^μ is extended to encompass γ5γμθ^μ can the Dirac-equation-form be conserved. The generalized vertex is useful in producing neutrino oscillations and mass differences.     

On gravity localization under Lorentz violation in warped scenario

Recently Rizzo studied the Lorentz Invariance Violation (LIV) in a brane scenario with one extra dimension where he found a non-zero mass for the four-dimensional graviton. This leads to the conclusion that five-dimensional models with LIV are not phenomenologically viable. In this work we re-examine the issue of Lorentz Invariance Violation in the context of higher-dimensional theories. We show that a six-dimensional geometry describing a string-like defect with a bulk-dependent cosmological constant can yield a massless 4D graviton, if we allow the cosmological constant variation along the bulk, and thus can provides a phenomenologically viable solution for the gauge hierarchy problem.     

New theory of Lorentz violation from a general principle

We report that a general principle of physical independence of mathematical background manifolds brings a replacement of common derivative operators by co-derivative ones. Then we obtain a new Lagrangian for the ordinary minimal standard model with supplementary terms containing the Lorentz invariance violation information measured by a new matrix, denoted as the Lorentz invariance violation matrix. We thus provide a new fundamental theory to study Lorentz invariance violation effects consistently and systematically.     

Discrete Space-Time and Lorentz Symmetry

Recent observations of Ultra High Energy Cosmic rays suggest a small violation of Lorentz symmetry. Such a violation is expected in schemes with discrete/quantized space-time. We examine this situation and suggest tests which could be carried out by, for example NASA's forthcoming GLAST Satellite.     

Weighted power counting and Lorentz violating gauge theories. I: General properties

We construct local, unitary gauge theories that violate Lorentz symmetry explicitly at high energies and are renormalizable by weighted power counting. They contain higher space derivatives, which improve the behavior of propagators at large momenta, but no higher time derivatives. We show that the regularity of the gauge-field propagator privileges a particular spacetime breaking, the one into space and time. We then concentrate on the simplest class of models, study four dimensional examples and discuss a number of issues that arise in our approach, such as the low-energy recovery of Lorentz invariance.     

Weighted power counting and Lorentz violating gauge theories. II: Classification

We classify the local, polynomial, unitary gauge theories that violate Lorentz symmetry explicitly at high energies and are renormalizable by weighted power counting. We study the structure of such theories and prove that renormalization does not generate higher time derivatives. We work out the conditions to renormalize vertices that are usually non-renormalizable, such as the two scalar-two fermion interactions and the four fermion interactions. A number of four-dimensional examples are presented.     

Entropic information for travelling solitons in Lorentz and CPT breaking systems

In this work we group four research topics apparently disconnected, namely solitons, Lorentz symmetry breaking, supersymmetry, and entropy. Following a recent work (Gleiser and Stamatopoulos, 2012), we show that it is possible to construct in the context of travelling wave solutions a configurational entropy measure in functional space, from the field configurations. Thus, we investigate the existence and properties of travelling solitons in Lorentz and CPT breaking scenarios for a class of models with two interacting scalar fields. Here, we obtain a complete set of exact solutions for the model studied which display both double and single-kink configurations. In fact, such models are very important in applications that include Bloch branes, Skyrmions, Yang–Mills, Q-balls, oscillons and various superstring-motivated theories. We find that the so-called Configurational Entropy (CE) for travelling solitons shows that the best value of parameter responsible to break the Lorentz symmetry is one where the energy density is distributed equally around the origin. In this way, the information-theoretical measure of travelling solitons in Lorentz symmetry violation scenarios opens a new window to probe situations where the parameters responsible for breaking the symmetries are arbitrary. In this case, the CE selects the best value of the parameter in the model.     

Spatial curvature and large scale Lorentz violation

The tension between the Hubble constant values obtained from local measurements and cosmic microwave background (CMB) measurements has motivated us to consider the cosmological model beyond ΛCDM. We investigate the cosmology in the large scale Lorentz violation model with a non-vanishing spatial curvature. The degeneracy among spatial curvature, cosmological constant, and cosmological contortion distribution makes the model viable in describing the known observational data. We obtain some constraints on the spatial curvature by comparing the relationship between measured distance modulus and red-shift with the predicted one, the evolution of matter density over time, and the evolution of effective cosmological constant. The implications of the large scale Lorentz violation model with the non-vanishing spatial curvature under these constrains are discussed.     

Relativistic Anandan quantum phase in the Lorentz violation background

We study the influence of a classical background based on the violation of the Lorentz symmetry on the relativistic Anandan quantum phase. We show that the choice of the Lorentz symmetry violation background provides an abelian contribution for the relativistic Anandan quantum phase.     

Looking for a Possible Breakdown of Local Lorentz Invariance for Electromagnetic Phenomena: Theory and First Experimental Results

We propose a new electromagnetic test of breakdown of local Lorentz invariance. It is based essentially on the detection of a non-zero force between a circular steady current and a charge, both at rest in the Earth frame. A preliminary experimental run gave a positive evidence for such an effect, which appears strongly dependent on the orientation of the circuit. Possible theoretical interpretations are briefly discussed.     

Dynamical CP violation of the generalized Yang-Mills model

Starting from the generalized Yang-Mills model which contains, besides the vector part Vμ, also a scalar part S and a pseudoscalar part P. It is shown, in terms of the Nambu-Jona-Lasinio (NJL) mechanism,that CP violation can be realized dynamically. The combination of the generalized Yang-MiUs model and the NJL mechanism provides a new way to explain CP violation.     

Dynamical CP violation of the generalized Yang-Mills model

Starting from the generalized Yang-Mills model which contains, besides the vector part V_μ, also a scalar part S and a pseudoscalar part P. It is shown, in terms of the Nambu-Jona-Lasinio (NJL) mechanism, that CP violation can be realized dynamically. The combination of the generalized Yang-Mills model and the NJL mechanism provides a new way to explain CP violation.     

电荷-宇称(CP)对称性破坏和夸克-轻子味物理——写在CP破坏发现和夸克理论提出40周年之际

简要地介绍了与电荷-宇称（CP）对称性破坏和夸克-轻子味物理有关的一些重要进展.从1964年发现CP破坏和提出夸克理论至今,这个领域就一直成为粒子物理研究的前沿领域,已研究和发展了整整40年,取得了许多辉煌的成就.在这篇文章中,着重评述了目前仍然热门的几个主要的研究方向：直接CP 破坏的理论研究和实验验证,CP破坏机制和新的CP破坏源,中微子物理和新的味物理,夸克味物理和有效量子场理论,标准模型中味物理参数的预言和超对称大统一理论.同时对我国有关研究组在这些前沿方向做出的重要贡献作了重点简述.可以看出,在CP破坏和味物理这个重要前沿领域,仍然存在着许多未解之谜,使得粒子物理在21世纪既面临着巨大的挑战,又有着不断发展的机遇.