Confinement in Maxwell-Chern-Simons Planar Quantum Electrodynamics and the 1/N approximation

We study the analytical structure of the fermion propagator in planar quantum electrodynamics coupled to a Chern-Simons term within a four-component spinor formalism. The dynamical generation of parity-preserving and parity-violating fermion mass terms is considered, through the solution of the corresponding Schwinger-Dyson equation for the fermion propagator at leading order of the 1/N approximation in Landau gauge. The theory undergoes a first order phase transition toward chiral symmetry restoration when the Chern-Simons coefficient $\theta$ reaches a critical value which depends upon the number of fermion families considered. Parity-violating masses, however, are generated for arbitrarily large values of the said coefficient. On the confinement scenario, complete charge screening --characteristic of the 1/N approximation-- is observed in the entire $(N,\theta)$-plane through the local and global properties of the vector part of the fermion propagator.Comment: 8 pages, 14 eps figures. Accepted in Phys. Rev.

Dynamical Mass Generation and Confinement in Maxwell-Chern-Simons Planar Quantum Electrodynamics

We study the non-perturbative phenomena of Dynamical Mass Generation and Confinement by truncating at the non-perturbative level the Schwinger-Dyson equations in Maxwell-Chern-Simons planar quantum electrodynamics. We obtain numerical solutions for the fermion propagator in Landau gauge within the so-called rainbow approximation. A comparison with the ordinary theory without the Chern-Simons term is presented.Comment: 9 pages, 9 figures; prepared for the XIV Mexican School of Particles and Fields, 4-12 November 2010, Morelia, Michoacan, Mexic

PENDAPATAN DAN FUNGSI PRODUKSI JAGUNG Studi Kasus Pada Usaha Tani Jagung Di Pedukuhan Sawah, Monggol, Saptosari, Gunungkidul Tahun 2013

Penelitian ini bertujuan untuk mengetahui besarnya pendapatan petani jagung dan menganalisis faktor-faktor yang mempengaruhi produksi jagung di pedukuhan Sawah dalam satu kali musim tanam tahun 2013. Data yang digunakan adalah data primer. Data primer diperoleh melalui survei lapangan. Hasil penelitian menunjukkan bahwa produktivitas rata-rata lahan jagung di pedukuhan Sawah dalam satu kali musim tanam adalah 50,87 kw/ha. Total biaya yang dikeluarkan untuk mengolah satu hektar lahan tani jagung dalam satu kali musim tanam di pedukuhan Sawah adalah Rp. 16.671.701, sedangkan total penerimaan yang diterima petani jagung dalam mengolah satu hektar lahan tani jagung adalah Rp. 19.344.926. Pendapatan bersih yang diterima petani jagung dalam mengolah satu hektar lahan tani jagung adalah Rp. 2.673.225. Berdasarkan analisis regresi model fungsi produksi Cobb-Douglas menunjukkan variabel luas lahan (0,113697) dan tenaga kerja (0,497813) dalam satu kali musim tanam berpengaruh signifikan terhadap produksi jagung. Setiap kenaikkan luas lahan sebesar 1% maka akan menyebabkan kenaikkan produksi jagung sebesar 0,11%. Setiap kenaikkan tenaga kerja sebesar 1% maka akan menyebabkan kenaikkan produksi jagung sebesar 0,49%. Analisis statistik menunjukkan nilai koefisien determinasi (R2) adalah 0,7633. Nilai dari probabilitas uji F-statistik signifikan pada α 5%. Jumlah dari masing-masing koefisien regresi input (�� � �� � �� � �� � ��� adalah 0,96. Penjumlahan koefisien dari masing-masing input kurang dari 1 (0,96<1). Hal ini berarti fungsi produksinya menunjukkan hasil balik ke skala yang menurun atau decreasing return to scale (DRTS). Artinya jika input dinaikkan 1% maka besarnya output juga akan bertambah namun kurang dari 0,96%

Massive Dirac fermions and the zero field quantum Hall effect

Through an explicit calculation for a Lagrangian in quantum electrodynamics in (2+1)-space--time dimensions (QED$_3$), making use of the relativistic Kubo formula, we demonstrate that the filling factor accompanying the quantized electrical conductivity for massive Dirac fermions of a single species in two spatial dimensions is a half (in natural units) when time reversal and parity symmetries of the Lagrangian are explicitly broken by the fermion mass term. We then discuss the most general form of the QED$_3$ Lagrangian, both for irreducible and reducible representations of the Dirac matrices in the plane, with emphasis on the appearance of a Chern-Simons term. We also identify the value of the filling factor with a zero field quantum Hall effect (QHE).Comment: 15 pages. Accepted in Jour. Phys.

Chiral Symmetry Breaking and Confinement Beyond Rainbow-Ladder Truncation

A non-perturbative construction of the 3-point fermion-boson vertex which obeys its Ward-Takahashi or Slavnov-Taylor identity, ensures the massless fermion and boson propagators transform according to their local gauge covariance relations, reproduces perturbation theory in the weak coupling regime and provides a gauge independent description for dynamical chiral symmetry breaking (DCSB) and confinement has been a long-standing goal in physically relevant gauge theories such as quantum electrodynamics (QED) and quantum chromodynamics (QCD). In this paper, we demonstrate that the same simple and practical form of the vertex can achieve these objectives not only in 4-dimensional quenched QED (qQED4) but also in its 3-dimensional counterpart (qQED3). Employing this convenient form of the vertex \emph{ansatz} into the Schwinger-Dyson equation (SDE) for the fermion propagator, we observe that it renders the critical coupling in qQED4 markedly gauge independent in contrast with the bare vertex and improves on the well-known Curtis-Pennington construction. Furthermore, our proposal yields gauge independent order parameters for confinement and DCSB in qQED3.Comment: 8 pages, 6 figure

Formal Analysis of V2X Revocation Protocols

Research on vehicular networking (V2X) security has produced a range of security mechanisms and protocols tailored for this domain, addressing both security and privacy. Typically, the security analysis of these proposals has largely been informal. However, formal analysis can be used to expose flaws and ultimately provide a higher level of assurance in the protocols. This paper focusses on the formal analysis of a particular element of security mechanisms for V2X found in many proposals: the revocation of malicious or misbehaving vehicles from the V2X system by invalidating their credentials. This revocation needs to be performed in an unlinkable way for vehicle privacy even in the context of vehicles regularly changing their pseudonyms. The REWIRE scheme by Forster et al. and its subschemes BASIC and RTOKEN aim to solve this challenge by means of cryptographic solutions and trusted hardware. Formal analysis using the TAMARIN prover identifies two flaws with some of the functional correctness and authentication properties in these schemes. We then propose Obscure Token (OTOKEN), an extension of REWIRE to enable revocation in a privacy preserving manner. Our approach addresses the functional and authentication properties by introducing an additional key-pair, which offers a stronger and verifiable guarantee of successful revocation of vehicles without resolving the long-term identity. Moreover OTOKEN is the first V2X revocation protocol to be co-designed with a formal model.Comment: 16 pages, 4 figure

Facets of confinement and dynamical chiral symmetry breaking

The gap equation is a cornerstone in understanding dynamical chiral symmetry breaking and may also provide clues to confinement. A symmetry-preserving truncation of its kernel enables proofs of important results and the development of an efficacious phenomenology. We describe a model of the kernel that yields: a momentum-dependent dressed-quark propagator in fair agreement with quenched lattice-QCD results; and chiral limit values: f_pi= 68 MeV and = -(190 MeV)^3. It is compared with models inferred from studies of the gauge sector.Comment: 5 pages, 3 figures; contribution to the proceedings of Quark Nuclear Physics (QNP 2002), Juelich, Germany, 9-14 Jun 200