Holomorphic Parafermions in the Potts model and SLE

We analyse parafermionic operators in the Q-state Potts model from three different perspectives. First, we explicitly construct lattice holomorphic observables in the Fortuin-Kasteleyn representation, and point out some special simplifying features of the particular case Q=2 (Ising model). In particular, away from criticality, we find a lattice generalisation of the massive Majorana fermion equation. We also compare the parafermionic scaling dimensions with known results from CFT and Coulomb gas methods in the continuum. Finally, we show that expectation values of these parafermions correspond to local observables of the SLE process which is conjectured to describe the scaling limit of the Q-state Potts model.Comment: 18 pages. v2: references to related work clarified. v3: minor corrections, version accepted for publication in JSTA

Excitons and charged excitons in semiconductor quantum wells

A variational calculation of the ground-state energy of neutral excitons and of positively and negatively charged excitons (trions) confined in a single-quantum well is presented. We study the dependence of the correlation energy and of the binding energy on the well width and on the hole mass. The conditional probability distribution for positively and negatively charged excitons is obtained, providing information on the correlation and the charge distribution in the system. A comparison is made with available experimental data on trion binding energies in GaAs-, ZnSe-, and CdTe-based quantum well structures, which indicates that trions become localized with decreasing quantum well width.Comment: 9 pages, 11 figure

Magnetic field dependence of the energy of negatively charged excitons in semiconductor quantum wells

A variational calculation of the spin-singlet and spin-triplet state of a negatively charged exciton (trion) confined to a single quantum well and in the presence of a perpendicular magnetic field is presented. We calculated the probability density and the pair correlation function of the singlet and triplet trion states. The dependence of the energy levels and of the binding energy on the well width and on the magnetic field strength was investigated. We compared our results with the available experimental data on GaAs/AlGaAs quantum wells and find that in the low magnetic field region (B<18 T) the observed transition are those of the singlet and the dark triplet trion (with angular momentum $L_z=-1$), while for high magnetic fields (B>25 T) the dark trion becomes optically inactive and possibly a transition to a bright triplet trion (angular momentum $L_z=0$) state is observed.Comment: 9 pages, 10 figures submitted to Phys. Rev.

Apprendi and Plea Bargaining

Before Apprendi , prosecutors using recidivism as a club could, and did, regularly insist that defendants admit aggravating facts as part of the plea or face additional time. When the prosecutor\u27s threats of added time were not persuasive and the proof of aggravating facts weak, the defendant prior to Apprendi could refuse to admit to the aggravating fact, and plead guilty only to the offense without the aggravating fact. Nothing about Apprendi gives additional leverage to the prosecutor in this situation. A defendant who, prior to Apprendi , decided to risk trial rather than face the aggravated sentence will make the same decision after Apprendi . In fact, only one new bargaining chip is created in Apprendi , and the Court gives it unequivocally to the defendant. By raising the burden of proof, Apprendi makes it much more difficult for the prosecutor to prove aggravating facts that trigger longer sentences

Essential Elements

The Court has struggled for well over a century with the issue of who has final authority to define what is a crime for purposes of applying procedural protections guaranteed by the Constitution in criminal cases. Just as labeling an action civil may allow the government to circumvent constitutional criminal procedure entirely, so labeling a fact an affirmative defense or a sentencing factor instead of an element of the offense may allow the government to escape constitutional criminal procedure selectively, bypassing the burden of proof, pleading, and jury requirements that would otherwise apply to an offense element. In its decision in Apprendi v. New Jersey, the Court put to rest one aspect of this ongoing battle about the significance of labels, declaring that any fact, other than a prior conviction, that increases the penalty for an offense beyond the prescribed statutory maximum must be submitted to a jury and proven beyond a reasonable doubt. But even as Apprendi settled one dispute, it uncovered others. The Court also recognized the possibility that legislatures might simply amend some of the many criminal statutes affected by this rule, in order to avoid full-blown trial adjudication of sentence-enhancing facts. Our examination of the response by every state legislature and Congress to seven major Supreme Court decisions allowing a change in substantive criminal law to effectuate a relaxation in procedures indicates that there will, in fact, be post-Apprendi evasion. Stating only that any effort to avoid the Apprendi rule by redrafting criminal statutes will be subject to constitutional scrutiny, the Court invited litigation over the constitutionality of substantive criminal law, but offered few clues about what shape that constitutional scrutiny should take. We take up this challenge. Drawing guidance from the rich and varied history of constitutional regulation of the substantive criminal law under many different constitutional provisions (including the Court\u27s most recent efforts to police the civil/criminal divide) we develop here a modest multi-factor test to help courts identify those few statutes that contain facts designated as non-elements by a legislature that, nonetheless, quack like elements under the Constitution

IMPELEMENTASI SAK 45 – LAPORAN KEUANGAN NIRLABA PADA MASJID MUHAMMADIYAH KOTA MEDAN

Penelitian ini bertujuan untuk melakukan kajian guna memberikan informasi tentang penerapan akuntansi mesjid di lingkungan mesjid Muhammadiyah di Kota Medan. Selanjutnya akan menyusun rekomendasi aksi kunci/tindakan untuk menyusun laporan keuangan masjid yang sesuai dengan Standar Akuntansi Keuangan (SAK) No. 45. Menurut SAK No. 45 laporan keuangan untuk masjid terdiri dari laporan posisi keuangan, laporan aktivitas, laporan arus kas, dan catatan atas laporan keuangan. Pada umumnya pengurus atau penanggungjawab yang menerima amanat dari masyarakat di sekitar lingkungan masjid, terkait dengan konsep akuntabilitas. Akuntansi sebagai sarana pertanggungjawaban akuntabilitas merupakan bagian yang integral dengan laporan keuangan masjid, sehingga suatu laporan keuangan perlu disajikan oleh masjid sesuai SAK No. 45. Dari hasil pengamatan bahwa umumnya Masjid Muhammadiyah masih menggunakan pendekatan akuntansi berbasis kas. dan belum menerapkan PSAK 45 karena sumberdaya manusia belum mampu menerapkan akuntansi berbasis akrual

Survival Regression Models With Dependent Bayesian Nonparametric Priors

We present a novel Bayesian nonparametric model for regression in survival analysis. Our model builds on the classical neutral to the right model of Doksum and on the Cox proportional hazards model of Kim and Lee. The use of a vector of dependent Bayesian nonparametric priors allows us to efficiently model the hazard as a function of covariates while allowing nonproportionality. The model can be seen as having competing latent risks. We characterize the posterior of the underlying dependent vector of completely random measures and study the asymptotic behavior of the model. We show how an MCMC scheme can provide Bayesian inference for posterior means and credible intervals. The method is illustrated using simulated and real data. Supplementary materials for this article are available online

Magpie: towards a semantic web browser

Web browsing involves two tasks: finding the right web page and then making sense of its content. So far, research has focused on supporting the task of finding web resources through ‘standard’ information retrieval mechanisms, or semantics-enhanced search. Much less attention has been paid to the second problem. In this paper we describe Magpie, a tool which supports the interpretation of web pages. Magpie offers complementary knowledge sources, which a reader can call upon to quickly gain access to any background knowledge relevant to a web resource. Magpie automatically associates an ontologybased semantic layer to web resources, allowing relevant services to be invoked within a standard web browser. Hence, Magpie may be seen as a step towards a semantic web browser. The functionality of Magpie is illustrated using examples of how it has been integrated with our lab’s web resources