957 resultados para Lorentz violation
Resumo:
Recent research suggests that aggressive driving may be influenced by driver perceptions of their interactions with other drivers in terms of ‘right’ or ‘wrong’ behaviour. Drivers appear to take a moral standpoint on ‘right’ or ‘wrong’ driving behaviour. However, ‘right’ or ‘wrong’ in the context of road use is not defined solely by legislation, but includes informal rules that are sometimes termed ‘driving etiquette’. Driving etiquette has implications for road safety and public safety since breaches of both formal and informal rules may result in moral judgement of others and subsequent behaviours designed to punish the ‘offender’ or ‘teach them a lesson’. This paper outlines qualitative research that was undertaken with drivers to explore their understanding of driving etiquette and how they reacted to other drivers’ observance or violation of their understanding. The aim was to develop an explanatory framework within which the relationships between driving etiquette and aggressive driving could be understood, specifically moral judgement of other drivers and punishment of their transgression of driving etiquette. Thematic analysis of focus groups (n=10) generated three main themes: (1) courtesy and reciprocity, and the notion of two-way responsibility, with examples of how expectations of courteous behaviour vary according to the traffic interaction; (2) acknowledgement and shared social experience: ‘giving the wave’; and (3) responses to breaches of the expectations/informal rules. The themes are discussed in terms of their roles in an explanatory framework of the informal rules of etiquette and how interactions between drivers can reinforce or weaken a driver’s understanding of driver etiquette and potentially lead to driving aggression.
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Non-Abelian quantum Hall states are characterized by the simultaneous appearance of charge and neutral gapless edge modes, with the structure of the latter being intricately related to the existence of bulk quasiparticle excitations obeying non-Abelian statistics. Here we propose a scenario for detecting the neutral modes by having two point contacts in series separated by a distance set by the thermal equilibration length of the charge mode. We show that by using the first point contact as a heating device, the excess charge noise measured at the second point contact carries a nontrivial signature of the presence of the neutral mode. We also obtain explicit expressions for the thermal conductance and corresponding Lorentz number for transport across a quantum point contact between two edges held at different temperatures and chemical potentials.
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[Excerpt] The Convention on the Rights of the Child (CRC) was one of the first international instruments to which the Republic of Uzbekistan acceded, and with parliamentary ratification on 9 December 1992, the Republic of Uzbekistan entered into a commitment to observe all the provisions of the CRC and to shoulder its responsibility before the international community. As a result various legislative, administrative and other steps have been taken by the government of the Republic of Uzbekistan with a view to bringing the State policy and legislation on children to be in line with the provisions as enshrined in the Convention on the Rights of the Child. The Constitution incorporates the fundamental provisions of the Universal Declaration of Human Rights. At the current stage in the restructuring of the country’s social and economic development, solid foundations have been laid for the conduct of significant democratic reforms based on a recognition of the innate worth of the individual (including the child) and of the unconditional respect of his or her rights and freedoms. Until recently, the State acted as the main guarantor of the provision of all social services, however the process of the transition (political/economic) to a market economy has entailed the development of new economic relations with a reduction in the allocation of state resources for the provision of social services to children. The efforts of the government made so far to bring the state policy and legislation on the child to be in line with the provisions enshrined in the convention on the rights of the child are commendable; never the less, the implementations of all these policies and laws into practice needs a lot to desire as there are a number of ongoing child rights violations. The National Report has fundamentally overlooked a number of child rights privileges enshrined in the CRC that have not yet been realised, or those rights that have been eroded since the independence. These shortcomings need to be noted for consideration so that the state steps up its efforts to enact new laws and/or to enforce the existing rules and regulations required for the protection and implementation of these child rights, and to improve the overall situation for children in the Republic of Uzbekistan.
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We discuss the consistency, unitarity and Lorentz invariance of an anomalous U(1) gauge theory in four dimensions. Our analysis is based on an effective low-energy action valid in the chiral symmetry broken phase. The allegedly bad properties of anomalous theories (except non-renormalizability) are examined. It is shown that, in the low-energy context, the theory can be consistently and unitarily quantised, and is formally Lorentz covariant.
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We analyze the relationship between tripartite entanglement and genuine tripartite nonlocality for three-qubit pure states in the Greenberger-Horne-Zeilinger class. We consider a family of states known as the generalized Greenberger-Horne-Zeilinger states and derive an analytical expression relating the three-tangle, which quantifies tripartite entanglement, to the Svetlichny inequality, which is a Bell-type inequality that is violated only when all three qubits are nonlocally correlated. We show that states with three-tangle less than 1/2 do not violate the Svetlichny inequality. On the other hand, a set of states known as the maximal slice states does violate the Svetlichny inequality, and exactly analogous to the two-qubit case, the amount of violation is directly related to the degree of tripartite entanglement. We discuss further interesting properties of the generalized Greenberger-Horne-Zeilinger and maximal slice states.
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Attitudes, knowledge, and perceptions of an individual influence their behavior as well as culture of a society. The objective of the study was to understand the attitudes and knowledge of 584 Indian community members regarding child rights and their perceptions about whether selected child rights were secured in reality. Overall attitudes of vast majority (96 – 98%) of the participants towards child rights were found to be positive i.e., children should have rights in various respects except issue like right to meet others (Article 15 of CRC). Knowledge of majority of the participants about child rights related legislations was moderate and varied across the cities while participants were unanimous about poor lived experiences of child rights in reality. So far as attitude and perception are concerned about child rights, there was a significant difference in the distribution between cities (p<0.01). Overall, the Rights of Children to Free and Compulsory Education Act, 2009 had the highest awareness (91.3%, n=533), followed by the Child Labour (Prohibition and Regulation) Act, 1986 (89.7%, n=523) and the Prohibition of Child Marriage Act, 2006 (89.6%, n=523). Findings of the present study speak in favor of community awareness about child rights and penalties for violation of child rights.
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Using electron spin resonance spectroscopy (ESR), we measure the rotational mobility of probe molecules highly diluted in deeply supercooled bulk water and negligibly constrained by the possible ice fraction. The mobility increases above the putative glass transition temperature of water, T-g = 136 K, and smoothly connects to the thermodynamically stable region by traversing the so called "no man's land" (the range 150-235 K), where it is believed that the homogeneous nucleation of ice suppresses the liquid water. Two coexisting fractions of the probe molecules are evidenced. The 2 fractions exhibit different mobility and fragility; the slower one is thermally activated (low fragility) and is larger at low temperatures below a fragile-to-strong dynamic cross-over at approximate to 225 K. The reorientation of the probe molecules decouples from the viscosity below approximate to 225 K. The translational diffusion of water exhibits a corresponding decoupling at the same temperature [Chen S-H, et al. (2006) The violation of the Stokes-Einstein relation in supercooled water. Proc Natl Acad Sci USA 103:12974-12978]. The present findings are consistent with key issues concerning both the statics and the dynamics of supercooled water, namely the large structural fluctuations [Poole PH, Sciortino F, Essmann U, Stanley HE (1992) Phase behavior of metastable water. Nature 360: 324-328] and the fragile-to-strong dynamic cross-over at approximate to 228 K [Ito K, Moynihan CT, Angell CA (1999) Thermodynamic determination of fragility in liquids and a fragile-tostrong liquid transition in water. Nature 398: 492-494].
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In supersymmetric theories with R-parity violation, squarks and sleptons can mediate Standard Model fermion–fermion scattering processes. These scalar exchanges in e+e− initiated reactions can give new signals at future linear colliders. We explore use of transverse beam polarization in the study of these signals in the process View the MathML source. We highlight certain asymmetries, which can be constructed due to the existence of the transverse beam polarization, which offer discrimination from the Standard Model (SM) background and provide increased sensitivity to the R-parity violating couplings.
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The influence of Lorentz and Doppler line-broadening mechanisms on the small-signal optical gain of lasers and, in particular, gasdynamic lasers, is discussed. A relationship between the critical parameter reflecting the line-broadening mechanisms and some of the important parameters arising out of the gain optimization studies in CO2-N2 gasdynamic lasers is established. Using this relationship, methods by which the deleterious effect of the Doppler mechanisms on small-signal gain can be suppressed are suggested. Journal of Applied Physics is copyrighted by The American Institute of Physics.
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The efforts of combining quantum theory with general relativity have been great and marked by several successes. One field where progress has lately been made is the study of noncommutative quantum field theories that arise as a low energy limit in certain string theories. The idea of noncommutativity comes naturally when combining these two extremes and has profound implications on results widely accepted in traditional, commutative, theories. In this work I review the status of one of the most important connections in physics, the spin-statistics relation. The relation is deeply ingrained in our reality in that it gives us the structure for the periodic table and is of crucial importance for the stability of all matter. The dramatic effects of noncommutativity of space-time coordinates, mainly the loss of Lorentz invariance, call the spin-statistics relation into question. The spin-statistics theorem is first presented in its traditional setting, giving a clarifying proof starting from minimal requirements. Next the notion of noncommutativity is introduced and its implications studied. The discussion is essentially based on twisted Poincaré symmetry, the space-time symmetry of noncommutative quantum field theory. The controversial issue of microcausality in noncommutative quantum field theory is settled by showing for the first time that the light wedge microcausality condition is compatible with the twisted Poincaré symmetry. The spin-statistics relation is considered both from the point of view of braided statistics, and in the traditional Lagrangian formulation of Pauli, with the conclusion that Pauli's age-old theorem stands even this test so dramatic for the whole structure of space-time.
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One of the unanswered questions of modern cosmology is the issue of baryogenesis. Why does the universe contain a huge amount of baryons but no antibaryons? What kind of a mechanism can produce this kind of an asymmetry? One theory to explain this problem is leptogenesis. In the theory right-handed neutrinos with heavy Majorana masses are added to the standard model. This addition introduces explicit lepton number violation to the theory. Instead of producing the baryon asymmetry directly, these heavy neutrinos decay in the early universe. If these decays are CP-violating, then they produce lepton number. This lepton number is then partially converted to baryon number by the electroweak sphaleron process. In this work we start by reviewing the current observational data on the amount of baryons in the universe. We also introduce Sakharov's conditions, which are the necessary criteria for any theory of baryogenesis. We review the current data on neutrino oscillation, and explain why this requires the existence of neutrino mass. We introduce the different kinds of mass terms which can be added for neutrinos, and explain how the see-saw mechanism naturally explains the observed mass scales for neutrinos motivating the addition of the Majorana mass term. After introducing leptogenesis qualitatively, we derive the Boltzmann equations governing leptogenesis, and give analytical approximations for them. Finally we review the numerical solutions for these equations, demonstrating the capability of leptogenesis to explain the observed baryon asymmetry. In the appendix simple Feynman rules are given for theories with interactions between both Dirac- and Majorana-fermions and these are applied at the tree level to calculate the parameters relevant for the theory.
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Quality of Service (QoS) is a new issue in cloud-based MapReduce, which is a popular computation model for parallel and distributed processing of big data. QoS guarantee is challenging in a dynamical computation environment due to the fact that a fixed resource allocation may become under-provisioning, which leads to QoS violation, or over-provisioning, which increases unnecessary resource cost. This requires runtime resource scaling to adapt environmental changes for QoS guarantee. Aiming to guarantee the QoS, which is referred as to hard deadline in this work, this paper develops a theory to determine how and when resource is scaled up/down for cloud-based MapReduce. The theory employs a nonlinear transformation to define the problem in a reverse resource space, simplifying the theoretical analysis significantly. Then, theoretical results are presented in three theorems on sufficient conditions for guaranteeing the QoS of cloud-based MapReduce. The superiority and applications of the theory are demonstrated through case studies.
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We apply our technique of using a Rb-stabilized ring-cavity resonator to measure the frequencies of various spectral components in the 555.8-nm 1S0-->3P1 line of Yb. We determine the isotope shifts with 60 kHz precision, which is an order-of-magnitude improvement over the best previous measurement on this line. There are two overlapping transitions, 171Yb(1/2-->3/2) and 173Yb(5/2-->3/2), which we resolve by applying a magnetic field. We thus obtain the hyperfine constants in the 3P1 state of the odd isotopes with a significantly improved precision. Knowledge of isotope shifts and hyperfine structure should prove useful for high-precision calculations in Yb necessary to interpret ongoing experiments testing parity and time-reversal symmetry violation in the laws of physics.
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The improvement terms in the generalised energy-momentum tensor of Callan, Coleman and Jackiw can be derived from a variational principle if the Lagrangian is generalised to describe coupling between ‘matter’ fields and a spin-2 boson field. The required Lorentz-invariant theory is a linearised version of Kibble-Sciama theory with an additional (generally-covariant) coupling term in the Lagrangian. The improved energy-momentum tensor appears as the source of the spin-2 field, if terms of second order in the coupling constant are neglected.
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We investigate use of transverse beam polarization in probing anomalous coupling of a Higgs boson to a pair of vector bosons, at the International Linear Collider (ILC). We consider the most general form of V V H (V = W/Z) vertex consistent with Lorentz invariance and investigate its effects on the process e(+)e(-) -> f (f) over barH, f being a light fermion. Constructing observables with definite C P and naive time reversal ((T) over tilde) transformation properties, we find that transverse beam polarization helps us to improve on the sensitivity of one part of the anomalous Z Z H Coupling that is odd under C P. Even more importantly it provides the possibility of discriminating from each other, two terms in the general Z Z H vertex, both of which are even under C P and (T) over bar. Use of transversebeam polarization when combined with information from unpolarized and linearly polarized beams therefore, allows one to have completely independent probes of all the different parts of a general ZZH vertex.