Decoherence and Recoherence in Model Quantum Systems

We discuss the various manifestations of quantum decoherence in the forms of dephasing, entanglement with the environment, and revelation of "which-path" information. As a specific example, we consider an electron interference experiment. The coupling of the coherent electrons to the quantized electromagnetic field illustrates all of these versions of decoherence. This decoherence has two equivalent interpretations, in terms of photon emission or in terms of Aharonov-Bohm phase fluctuations. We consider the case when the coherent electrons are coupled to photons in a squeezed vacuum state. The time-averaged result is increased decoherence. However, if only electrons which are emitted during selected periods are counted, the decoherence can be suppressed below the level for the photon vacuum. This is the phenomenon of recoherence. This effect is closely related to the quantum violations of the weak energy condition, and is restricted by similar inequalities. We give some estimates of the magnitude of the recoherence effect and discuss prospects for observing it in an electron interferometry experiment.Comment: 8 pages, 3 figures, talk presented at the 7th Friedmann Seminar, Joao Pessoa, Brazil, July 200

Kerjasama Interpol Dalam Penanganan International Crime Menurut Undang-undang Kepolisian Nomor 2 Tahun 2002

Tujuan dilakukannya penelitian ini adalah untuk mengetahui bagaimana pengaturan kerjasama Interpol menurut Undang-Undang kepolisian nomor 2 tahun 2002 dan bagaimana pelaksanaan kerjasama Interpol menurut Undang-Undang kepolisian nomor 2 tahun 2002. Dengan menggunakan metode penelitian yuridis normative dsimpulkan: 1. Pengaturan kerjasama Interpol menurut Undang-Undang kepolisian nomor 2 tahun 2002 adalah bahwa hubungan dan kerjasama luar negeri dilakukan terutama dengan badan-badan kepolisian dan penegak hukum lain melalui kerjasama bilateral atau multilateral dan badan pencegahan kejahatan baik dalam rangka tugas operasional maupun kerjasama teknik dan pendidikan serta pelatihan. 2. Pelaksanaan kerjasama Interpol menurut Undang-Undang kepolisian nomor 2 tahun 2002 Pasal 42 ayat (4) adalah diatur lebih lanjut dalam peraturan pemerintah yaitu Peraturan Pemerintah Republik Indonesia Nomor 68 Tahun 2008 tentang Tata Cara Pelaksanaan Kerjasama Kepolisian Negara Republik Indonesia yang terkandung dalam 19 Pasal

Status of Spin Physics - Experimental Summary

The current status of spin physics experiments, based on talks presented at the Third Circum-Pan-Pacific Symposium on High Energy Spin Physics held in Beijing, 2001, is summarized in this article. Highlights of recent experimental results at SLAC, JLab, and DESY, as well as future plans at these facilities and at RHIC-spin are discussed.Comment: 18 pages, 7 figures, Invited talk presented at the Third Circum-Pan-Pacific Symposium on High Energy Spin Physics held in Beijing, October, 200

Flux-ratio anomalies from discs and other baryonic structures in the Illustris simulation

The flux ratios in the multiple images of gravitationally lensed quasars can provide evidence for dark matter substructure in the halo of the lensing galaxy if the flux ratios differ from those predicted by a smooth model of the lensing galaxy mass distribution. However, it is also possible that baryonic structures in the lensing galaxy, such as edge-on discs, can produce flux-ratio anomalies. In this work, we present the first statistical analysis of flux-ratio anomalies due to baryons from a numerical simulation perspective. We select galaxies with various morphological types in the Illustris simulation and ray-trace through the simulated halos, which include baryons in the main lensing galaxies but exclude any substructures, in order to explore the pure baryonic effects. Our ray-tracing results show that the baryonic components can be a major contribution to the flux-ratio anomalies in lensed quasars and that edge-on disc lenses induce the strongest anomalies. We find that the baryonic components increase the probability of finding high flux-ratio anomalies in the early-type lenses by about 8% and by about 10 - 20% in the disc lenses. The baryonic effects also induce astrometric anomalies in 13% of the mock lenses. Our results indicate that the morphology of the lens galaxy becomes important in the analysis of flux-ratio anomalies when considering the effect of baryons, and that the presence of baryons may also partially explain the discrepancy between the observed (high) anomaly frequency and what is expected due to the presence of subhalos as predicted by the CDM simulations.Comment: 16 pages, 11 figures, accepted by MNRA