Gauge invariance of massless QED

A simple general proof of gauge invariance in QED is given in the framework of causal perturbation theory. It illustrates a method which can also be used in non-abelian gauge theories.Comment: 7 pages, TEX-file, Zuerich University Preprint ZU-TH-33/199

On Gauge Invariance and Spontaneous Symmetry Breaking

We show how the widely used concept of spontaneous symmetry breaking can be explained in causal perturbation theory by introducing a perturbative version of quantum gauge invariance. Perturbative gauge invariance, formulated exclusively by means of asymptotic fields, is discussed for the simple example of Abelian U(1) gauge theory (Abelian Higgs model). Our findings are relevant for the electroweak theory, as pointed out elsewhere.Comment: 13 pages, latex, no figure

Massive gravity from descent equations

Both massless and massive gravity are derived from descent equations (Wess-Zumino consistency conditions). The massive theory is a continuous deformation of the massless one.Comment: 8 pages, no figur

Regularization in quantum field theory from the causal point of view

The causal approach to perturbative quantum field theory is presented in detail, which goes back to a seminal work by Henri Epstein and Vladimir Jurko Glaser in 1973. Causal perturbation theory is a mathematically rigorous approach to renormalization theory, which makes it possible to put the theoretical setup of perturbative quantum field theory on a sound mathematical basis. Epstein and Glaser solved this problem for a special class of distributions, the time-ordered products, that fulfill a causality condition, which itself is a basic requirement in axiomatic quantum field theory. In their original work, Epstein and Glaser studied only theories involving scalar particles. In this review, the extension of the method to theories with higher spin, including gravity, is presented. Furthermore, specific examples are presented in order to highlight the technical differences between the causal method and other regularization methods, like, e.g. dimensional regularization.Comment: 75 pages, 8 figures, style file included, some comments and references adde

A possible dearth of hot gas in galaxy groups at intermediate redshift

We examine the X-ray luminosity of galaxy groups in the CNOC2 survey, at redshifts 0.1 < z < 0.6. Previous work examining the gravitational lensing signal of the CNOC2 groups has shown that they are likely to be genuine, gravitationally bound objects. Of the 21 groups in the field of view of the EPIC-PN camera on XMM-Newton, not one was visible in over 100 ksec of observation, even though three of the them have velocity dispersions high enough that they would easily be visible if their luminosities scaled with their velocity dispersions in the same way as nearby groups' luminosities scale. We consider the possibility that this is due to the reported velocity dispersions being erroneously high, and conclude that this is unlikely. We therefore find tentative evidence that groups at intermediate redshift are underluminous relative to their local cousins.Comment: 16 pages, 5 figures, reference added in section 1, typos corrected, published in Ap

On Terrorism and Whistleblowing

At a Bio-Terrorism Conference at Case Western Reserve University School of Law on March 31, 2006, the government participants were asked what they would do if a superior instructed them not to disclose information to the public about the likely grave health affects of an ongoing bio-terrorist attack. In response, they indicated that they would be reluctant to become a whistleblower. This is not surprising since, despite the federal and state laws that purport to facilitate such whistleblowing for the public good, government whistleblowers routinely have faced loss of promotion, harassment, firing, and in some instances criminal prosecution when they have gone public with their important information. Yet, without government whistleblowers who had the courage to go to the press, the public would never have learned about Watergate, the Iran-Contra scandal, the inhumane practices at Abu Ghraib prison in Iraq, the secret prisons run by the United States in Eastern Europe, or the NSA policy of wiretapping Americans without warrants. These disclosures initiated vital public debate and prompted corrective actions and reforms. The authors argue that the government whistleblower who in good faith discloses information to the press should no longer be treated as an enemy of the state, and provide a legislative proposal to give them a greater degree of protection from retaliation than exists under current legislation

The Standard Model and its Generalizations in Epstein-Glaser Approach to Renormalization Theory II: the Fermion Sector and the Axial Anomaly

We complete our study of non-Abelian gauge theories in the framework of Epstein-Glaser approach to renormalization theory including in the model an arbitrary number of Dirac Fermions. We consider the consistency of the model up to the third order of the perturbation theory. In the second order we obtain pure group theoretical relations expressing a representation property of the numerical coefficients appearing in the left and right handed components of the interaction Lagrangian. In the third order of the perturbation theory we obtain the the condition of cancellation of the axial anomaly.Comment: 38 pages, LATEX 2e, extensive rewritting, some errors eliminate

On Terrorism and Whistleblowing

At a Bio-Terrorism Conference at Case Western Reserve University School of Law on March 31, 2006, the government participants were asked what they would do if a superior instructed them not to disclose information to the public about the likely grave health affects of an ongoing bio-terrorist attack. In response, they indicated that they would be reluctant to become a whistleblower. This is not surprising since, despite the federal and state laws that purport to facilitate such whistleblowing for the public good, government whistleblowers routinely have faced loss of promotion, harassment, firing, and in some instances criminal prosecution when they have gone public with their important information. Yet, without government whistleblowers who had the courage to go to the press, the public would never have learned about Watergate, the Iran-Contra scandal, the inhumane practices at Abu Ghraib prison in Iraq, the secret prisons run by the United States in Eastern Europe, or the NSA policy of wiretapping Americans without warrants. These disclosures initiated vital public debate and prompted corrective actions and reforms. The authors argue that the government whistleblower who in good faith discloses information to the press should no longer be treated as an enemy of the state, and provide a legislative proposal to give them a greater degree of protection from retaliation than exists under current legislation

Adherence to Selected Air Carrier (Airline) Operational Regulations for Improved General Aviation Flight Safety in Degraded Visibility

Introduction: General aviation largely comprises fixed-wing piston-engine light aircraft (,12,500 lbs). Unfortunately, this civil aviation sector suffers a vastly inferior safety record when compared with air carriers (60- to 80-fold higher accident rate). Additionally, such mishaps pose a considerable financial burden to both the affected family and the United States: US$1.64–4.64 billion annually. We hypothesize that this safety disparity partly reflects more stringent operational regulations for air carriers. Herein, we determined whether compliance with six selected air carrier regulations could potentially reduce general aviation accidents in degraded visibility (IMC) the majority of which are fatal. Methods: Accidents (2005–2019) were identified from the National Transportation Safety Board Access database. Fleet data for rate calculations were per the general aviation survey and the Bureau of Transportation Statistics. Statistics used Poisson distributions. Results: Of 219 general aviation accidents in IMC, 43 (20%) could potentially have been averted had one, or more, of the selected air carrier regulations been complied with. The largest percentage (62%) of the 43 mishaps were due to pilots operating contrary to the air carrier regulation specifying takeoff or landing weather minimums. The second largest group related to more conservative weather minimums required for an inexperienced airline pilot-in-command, eschewed in 19% of preventable general aviation IMC mishaps. Conclusions: Alignment with the aforementioned air carrier operational rules could potentially blunt the IMC accident rate (by 20%) for general aviation. Practical Applications: Adherence to the aforementioned air carrier regulations should be advocated to general aviation pilots operating in IMC