Thermal partition function of photons and gravitons in a Rindler wedge

The thermal partition function of photons in any covariant gauge and gravitons in the harmonic gauge, propagating in a Rindler wedge, are computed using a local $\zeta$-function regularization approach. The correct Planckian leading order temperature dependence $T^4$ is obtained in both cases. For the photons, the existence of a surface term giving a negative contribution to the entropy is confirmed, as earlier obtained by Kabat, but this term is shown to be gauge dependent in the four-dimensional case and, therefore is discarded. It is argued that similar terms could appear dealing with any integer spin $s\geq 1$ in the massless case and in more general manifolds. Our conjecture is checked in the case of a graviton in the harmonic gauge, where different surface terms also appear, and physically consistent results arise dropping these terms. The results are discussed in relation to the quantum corrections to the black hole entropy.Comment: 29 pages, RevTeX, no figures. Minor errors corrected and a few comments changed since first submission. To be published on Phys.Rev.

Massive scalar field near a cosmic string

The $\zeta$ function of a massive scalar field near a cosmic string is computed and then employed to find the vacuum fluctuation of the field. The vacuum expectation value of the energy-momentum tensor is also computed using a point-splitting approach. The obtained results could be useful also for the case of self-interacting scalar fields and for the finite-temperature Rindler space theory.Comment: 15 pages, standard LaTeX, no figures. Reference [14] correcte

Full configuration interaction approach to the few-electron problem in artificial atoms

We present a new high-performance configuration interaction code optimally designed for the calculation of the lowest energy eigenstates of a few electrons in semiconductor quantum dots (also called artificial atoms) in the strong interaction regime. The implementation relies on a single-particle representation, but it is independent of the choice of the single-particle basis and, therefore, of the details of the device and configuration of external fields. Assuming no truncation of the Fock space of Slater determinants generated from the chosen single-particle basis, the code may tackle regimes where Coulomb interaction very effectively mixes many determinants. Typical strongly correlated systems lead to very large diagonalization problems; in our implementation, the secular equation is reduced to its minimal rank by exploiting the symmetry of the effective-mass interacting Hamiltonian, including square total spin. The resulting Hamiltonian is diagonalized via parallel implementation of the Lanczos algorithm. The code gives access to both wave functions and energies of first excited states. Excellent code scalability in a parallel environment is demonstrated; accuracy is tested for the case of up to eight electrons confined in a two-dimensional harmonic trap as the density is progressively diluted and correlation becomes dominant. Comparison with previous Quantum Monte Carlo simulations in the Wigner regime demonstrates power and flexibility of the method.Comment: RevTeX 4.0, 18 pages, 6 tables, 9 postscript b/w figures. Final version with new material. Section 6 on the excitation spectrum has been added. Some material has been moved to two appendices, which appear in the EPAPS web depository in the published versio

Ambiguity in the evaluation of the effective action on the cone

An ambiguity in the computation of the one-loop effective action for fields living on a cone is illustrated. It is shown that the ambiguity arises due to the non-commutativity of the regularization of ultraviolet and (conical) boundary divergencies.Comment: REVTeX file, 10 pages. Comments on recent papers have been adde

Genome data from a sixteenth century pig illuminate modern breed relationships

Ancient DNA (aDNA) provides direct evidence of historical events that have modeled the genome of modern individuals. In livestock, resolving the differences between the effects of initial domestication and of subsequent modern breeding is not straight forward without aDNA data. Here, we have obtained shotgun genome sequence data from a sixteenth century pig from Northeastern Spain (Montsoriu castle), the ancient pig was obtained from an extremely well-preserved and diverse assemblage. In addition, we provide the sequence of three new modern genomes from an Iberian pig, Spanish wild boar and a Guatemalan Creole pig. Comparison with both mitochondrial and autosomal genome data shows that the ancient pig is closely related to extant Iberian pigs and to European wild boar. Although the ancient sample was clearly domestic, admixture with wild boar also occurred, according to the D-statistics. The close relationship between Iberian, European wild boar and the ancient pig confirms that Asian introgression in modern Iberian pigs has not existed or has been negligible. In contrast, the Guatemalan Creole pig clusters apart from the Iberian pig genome, likely due to introgression from international breeds

Competing mechanisms for singlet-triplet transition in artificial molecules

We study the magnetic field induced singlet/triplet transition for two electrons in vertically coupled quantum dots by exact diagonalization of the Coulomb interaction. We identify the different mechanisms occurring in the transition, involving either in-plane correlations or localization in opposite dots, depending on the field direction. Therefore, both spin and orbital degrees of freedom can be manipulated by field strength and direction. The phase diagram of realistic devices is determined.Comment: To appear in Phys. Rev. B - Rapid Comm. - 5 pages, 3 figure

Bonding of the Inner Tracker Silicon Microstrip Modules

Microbonding of the CMS Tracker Inner Barrel (TIB) and Tracker Inner Disks (TID) modules was shared among six different Italian Institutes. The organization devised and the infrastructure deployed to handle this task is illustrated. Microbonding specifications and procedures for the different types of TIB and TID modules are given. The tooling specially designed and developed for these types of modules is described. Experience of production is presented. Attained production rates are given. An analysis of the microbonding quality achieved is presented, based on bond strengths measured in sample bond pull tests as well as on rates of bonding failures. Italian Bonding Centers routinely performed well above minimum specifications and a very low global introduced failure rate, at the strip level, of only $\sim$0.015 \% is observed

KETAHANAN TARIK CAMPURAN CTRB YANG MENGANDUNG 60% RAP DAN 40% RAM DENGAN SUBSTITUSI MATERIAL POZOLAN TERHADAP SEMEN

Kerusakan jalan yang terjadi pada lapis pondasi maka rehabilitasi yang harus dilakukan pada lapis pondasinya. Perbaikan yang sering dikakukan yaitu membongkar lapis pondasi yang rusak lalu menggantinya dengan material agregat batu pecah yang baru tanpa menggunakan bahan pengikat maupun menggunakan bahan pengikat berupa semen lalu dipadatkan. Dalam pelaksanaannya di lapangan, cara ini sering menghadapi tantangan yaitu secara ekonomi memerluka dana yang besar untuk pengadaan material baru, gangguan lingkungan hidup yaitu mengakibatkan daerah quarry, polusi udara dan degradasi lingkngan. Untuk mengatasi masalah tersebut maka salah satu teknologi daur ulang yaitu CTRB dapat digunakan. Campuran Cemen Treated Recycling Base (CTRB) adalah teknik daur ulang perkerasan jalan untuk lapis pondasi yang memanfaatkan RAP (Reclaimed Asphalt Pavement) yaitu material agregat yang mengandung aspal dan RAM (Reclaimed Aggregate Mineral) yaitu material agregat yang tidak mengandung aspal yang berasal dari garukan perkerasan yang telah rusak, dicampur kembali lalu distabilisasikan dengan semen. Semen sebagai bahan stabilisa pada campuran CTRB memerluka biaya yang besar. Oleh sebab itu akan disubstitusikan pozolan alam (tras) terhadap semen. Dalam penelitian ini dilakukan pengujian ITS (Indirect Tensile Strength). Dalam penelitian ini akukan dilpengujian ITS (Indirect Tensile Strength). Variasi semen yang dibuat yaitu 2%, 4%, 6%  terhadap RAP dan RAM dan variasi tras  0%, 15%, 30% terhadap semen. Variasi campuran semen dan tras yaitu 2% PC, 4% PC, 6% PC, 2% PC : 15% Tras, 4% PC : 15% Tras, 6% PC : 15% Tras, 2% PC : 30% Tras, 4% PC : 30% Tras, 6% PC : 30% Tras. Komposisi optimum campuran yang melampaui nilai ITS yaitu campuran CTRB 6% PC : 15 % Tras dan 6% PC : 30% Tras Kata Kunci: CTRB, RAP, RAM, Tras, ITS, Pozzola

deSpeckNet: Generalizing Deep Learning Based SAR Image Despeckling

Deep learning (DL) has proven to be a suitable approach for despeckling synthetic aperture radar (SAR) images. So far, most DL models are trained to reduce speckle that follows a particular distribution, either using simulated noise or a specific set of real SAR images, limiting the applicability of these methods for real SAR images with unknown noise statistics. In this paper, we present a DL method, deSpeckNet1, that estimates the speckle noise distribution and the despeckled image simultaneously. Since it does not depend on a specific noise model, deSpeckNet generalizes well across SAR acquisitions in a variety of landcover conditions. We evaluated the performance of deSpeckNet on single polarized Sentinel-1 images acquired in Indonesia, The Democratic Republic of Congo and The Netherlands, a single polarized ALOS-2/PALSAR-2 image acquired in Japan and an Iceye X2 image acquired in Germany. In all cases, deSpeckNet was able to effectively reduce speckle and restor