Nonuniqueness of the Fierz-Pauli mass term for a nonsymmetic tensor

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Reply to Comment on 'validity of Feynman's prescription of disregarding the Pauli principle in intermediate states'

In a recent paper, we raised a question on the validity of Feynman's prescription of disregarding the Pauli principle in intermediate states of perturbation theory. In the preceding Comment, Cavalcanti correctly pointed out that Feynman's prescription is consistent with the exact solution of the model that we used. This means that the Pauli principle does not necessarily apply to intermediate states. We discuss implications of this puzzling aspect.

Validity of Feynman's prescription of disregarding the Pauli principle in intermediate states

Regarding the Pauli principle in quantum field theory and in many-body quantum mechanics, Feynman advocated that Pauli's exclusion principle can be completely ignored in intermediate states of perturbation theory. He observed that all virtual processes (of the same order) that violate the Pauli principle cancel out. Feynman accordingly introduced a prescription, which is to disregard the Pauli principle in all intermediate processes. This ingenious trick is of crucial importance in the Feynman diagram technique. We show, however, an example in which Feynman's prescription fails. This casts doubts on the general validity of Feynman's prescription. [S1050-2947(99)04604-1].

Fierz-Pauli higher derivative gravity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The Schrodinger and Pauli-Dirac Oscillators in Noncommutative Phase Space

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

What is wrong with Pauli-Villars regularization in QED(3)?

In this paper we argue that there is no ambiguity between the Pauli-Villars and other methods of regularization in (2+1)-dimensional quantum electrodynamics with respect to dynamical mass generation, provided we properly choose the couplings for the regulators.

Pauli blocking and medium effects in nucleon knockout reactions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Pauli nonlocality in heavy-ion rainbow scattering: A further test of the folding model

Nonlocal interactions are an intrinsically quantum phenomenon. In this work we point out that, in the context of heavy ions, such interactions can be studied through the refractive elastic scattering of these systems at intermediate energies. We show that most of the observed energy dependence of the local equivalent bare potential arises from the exchange nonlocality. The nonlocality parameter extracted from the data was found to be very close to the one obtained from folding models. The effective mass of the colliding, heavy-ion, system was found to be close to the nucleon effective mass in nuclear matter.

Note on the nonuniqueness of the massive Fierz-Pauli theory and spectator fields

It is possible to show that there are three independent families of models describing a massive spin-2 particle via a rank-2 tensor. One of them contains the massive Fierz-Pauli model, the only case described by a symmetric tensor. The three families have different local symmetries in the massless limit and can not be interconnected by any local field redefinition. We show here, however, that they can be related with the help of a decoupled and nondynamic (spectator) field. The spectator field may be either an antisymmetric tensor B μν=-Bνμ, a vector Aμ or a scalar field φ, corresponding to each of the three families. The addition of the extra field allows us to formulate master actions which interpolate between the symmetric Fierz-Pauli theory and the other models. We argue that massive gravity models based on the Fierz-Pauli theory are not expected to be equivalent to possible local self-interacting theories built up on top of the two new families of massive spin-2 models. The approach used here may be useful to investigate dual (nonsymmetric) formulations of higher-spin particles. © 2013 American Physical Society.

Massive spin-2 particles via embedment of the Fierz-Pauli equations of motion

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Complex mixed state of the Pauli-limited superconductor CeCoIn5

Magnetization measurements were performed on CeCoIn5 at temperatures down to 20 mK and magnetic fields up to 17 T applied along different crystallographic orientations. For field configurations nearly parallel to the ab plane (theta less than or similar to 40 degrees and T <= 50 mK), we have found an intriguing vortex dynamics regime revealed by a hysteretic and metastable anomalous peak effect (APE), which gives evidence of surface barrier effects enhanced by antiferromagnetic fluctuations in the mixed state of CeCoIn5. Furthermore, we have observed crossover features in the torque and magnetization traces at fields below H-c2, which are consistent with vortices lattice phase transitions and with the anomalies speculated to be the Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) superconducting state in CeCoIn5. All of the above features were found to be dramatically perturbed in Ce0.98Gd0.02CoIn5.

Under the Crimson Flag: Fahle Burman's Two Trips to the Michigan Supreme Court

Erick Fahle Burman. a Swedish-born, Finnish-speaking labor and political activist, twice had cases argued on his behalf before the Michigan Supreme Court. In People vs. Burman, Burman, along with nine other defendants, had his conviction affirmed by the court and all ten were forced to pay a fine of $25 each for disturbing the peace. In People vs. Immonen, Burman and his co-defendant, Unto Immonen, had their convictions overturned because of improper evidence being admitted in their lower court trial. Though the conviction was overturned, the two men had already spent several months as prisoners at hard labor in Marquette State Prison located in Michigan's Upper Peninsula. Over twenty-five years separate Burman's two trips to Michigan's high court. On the first occasion, his arrest came less than five years after his arrival as an immigrant to the U. S. On the second occasion, his arrest came less than two years after his return to the state after being away for nearly two decades. On both occasions, Burman was arrested for his involvement with red flags. Though separated by decades, these cases, taken together, are important indicators of the state of Finnish-American radicalism in the years surrounding the red flag incidents and provide interesting insights into the delicacies of political suppression. Examination of these cases within the larger career of Fahle Burman points up his overlooked importance in the history of Finnish-American socialism and communism.

Plackett and Burman analysis to select effective compiler optimizations

Compiler optimizations help to make code run faster at runtime. When the compilation is done before the program is run, compilation time is less of an issue, but how do on-the-fly compilation and optimization impact the overall runtime? If the compiler must compete with the running application for resources, the running application will take more time to complete. This paper investigates the impact of specific compiler optimizations on the overall runtime of an application. A foldover Plackett and Burman design is used to choose compiler optimizations that appear to contribute to shorter overall runtimes. These selected optimizations are compared with the default optimization levels in the Jikes RVM. This method selects optimizations that result in a shorter overall runtime than the default O0, O1, and O2 levels. This shows that careful selection of compiler optimizations can have a significant, positive impact on overall runtime.