Role of entanglement in two-photon imaging

The use of entangled photons in an imaging system can exhibit effects that cannot be mimicked by any other two-photon source, whatever the strength of the correlations between the two photons. We consider a two-photon imaging system in which one photon is used to probe a remote (transmissive or scattering) object, while the other serves as a reference. We discuss the role of entanglement versus correlation in such a setting, and demonstrate that entanglement is a prerequisite for achieving distributed quantum imaging.Comment: 15 pages, 2 figure

Symmetric Autocompensating Quantum Key Distribution

We present quantum key distribution schemes which are autocompensating (require no alignment) and symmetric (Alice and Bob receive photons from a central source) for both polarization and time-bin qubits. The primary benefit of the symmetric configuration is that both Alice and Bob may have passive setups (neither Alice nor Bob is required to make active changes for each run of the protocol). We show that both the polarization and the time-bin schemes may be implemented with existing technology. The new schemes are related to previously described schemes by the concept of advanced waves.Comment: 4 pages, 2 figur

Generation of Entangled Photon Holes using Quantum Interference

In addition to photon pairs entangled in polarization or other variables, quantum mechanics also allows optical beams that are entangled through the absence of the photons themselves. These correlated absences, or ``entangled photon holes'', can lead to counter-intuitive nonlocal effects analogous to those of the more familiar entangled photon pairs. Here we report an experimental observation of photon holes generated using quantum interference effects to suppress the probability that two photons in a weak laser pulse will separate at an optical beam splitter.Comment: 4 pages, color figures, submitted to Phys. Rev.

Persistent X-Ray Photoconductivity and Percolation of Metallic Clusters in Charge-Ordered Manganites

Charge-ordered manganites of composition $\rm Pr_{1-x}(Ca_{1-y}Sr_{y})_{x}MnO_3$ exhibit persistent photoconductivity upon exposure to x-rays. This is not always accompanied by a significant increase in the {\it number} of conduction electrons as predicted by conventional models of persistent photoconductivity. An analysis of the x-ray diffraction patterns and current-voltage characteristics shows that x-ray illumination results in a microscopically phase separated state in which charge-ordered insulating regions provide barriers against charge transport between metallic clusters. The dominant effect of x-ray illumination is to enhance the electron {\it mobility} by lowering or removing these barriers. A mechanism based on magnetic degrees of freedom is proposed.Comment: 8 pages, 4 figure

Odd-Order Aberration-Cancellation in Correlated-Photon Imaging

We discuss a correlated two-photon imaging apparatus that is capable of producing images that are free of the effects of odd-order aberration introduced by the optical system. We show that both quantum-entangled and classically correlated light sources are capable of producing the desired spatial-aberration cancelation

Coherent Molecular Optics using Sodium Dimers

Coherent molecular optics is performed using two-photon Bragg scattering. Molecules were produced by sweeping an atomic Bose-Einstein condensate through a Feshbach resonance. The spectral width of the molecular Bragg resonance corresponded to an instantaneous temperature of 20 nK, indicating that atomic coherence was transferred directly to the molecules. An autocorrelating interference technique was used to observe the quadratic spatial dependence of the phase of an expanding molecular cloud. Finally, atoms initially prepared in two momentum states were observed to cross-pair with one another, forming molecules in a third momentum state. This process is analogous to sum-frequency generation in optics

Upaya Pemerintah Kelurahan dalam Rangka Pemberdayaan Pelayanan Masyarakat

Kualitas pelayanan yang diberikan kepada masyarakat saat ini telah mengalami penurunan dan perlu diadakan perbaikan, bila dilihat dari sisi efisiensi dan efektivitas kesamaan perlakuan (tidak diskriminatif) maka pelayanan yang diberikan masih jauh dari yang diharapkan oleh masyarakat dan masih memiliki berbagai kelemahan. Pemberian pelayanan kepada masyarakat diharapkan menjadi lebih responsif terhadap kepentingan masyarakat itu sendiri, pelayanan yang lebih memberikan fokus pada pengelolaan yang berorientasi kepuasan masyarakat. Jenis penelitian dalam penelitian ini adalah penelitian kualitatif, fokus penelitian yaitu pemberdayaan pelayanan bidang pendidikan, kesehatan ekonmi, teknik pengumpulan data yaitu observasi, wawancara, dokumentasi, teknik analisa data yaitu reduksi data, penyajian data, penarikan kesimpulan. Hasil penelitian pemberdayaan pelayanan Bidang Pendidikan yaitu dengan memberikan pembangunan dari tingkat PAUD sampai Perguruan Tinggi, memberikan rekomendasi kepada masyarakat kurang mampu; Bidang Kesehatan yaitu menyediakan fasilitas kesehatan yang memadai, merealisasikan Program Kesehatan yakni Jamkesmas, KB dan JKN; Bidang Ekonomi yaitu melakukan pendataan USAha kecil, menengah, membentuk kelompok USAha dan menfasilitasi pengajuan kredit, dan memberikan rekomendasi izin USAha; Wujud Dari Pemberdayaan Pelayanan Bidang Pendidikan adalah seluruh masyarakat memperoleh pendidikan yang sama, dan berkualitas; Bidang Kesehatan yaitu masyarakat memiliki hak yang sama dalam memperoleh kesehatan, masyarakat memahami pola hidup sehat; Bidang Ekonomi yaitu masyarakat memiliki daya saing yang tinggi untuk mendirikan USAha, dan hasil USAha masyarakat semakin meningkat. Kata Kunci: Pemberdayaan Pendidikan, Kesehatan, Ekonomi

Evaluasi Kebijakan Nasionalisasi Pertanahan

Evaluasi terhadap implementasi UU No.1/2003 di Timor Leste. Tujuan penelitian ini untuk mendeskripsikan, mengevaluasi dan menganalisis proses nasionalisasi eks-tanah dan bangunan yang ditinggalkan oleh pemiliknya dan pemerintahan Indonesia dan Portugis yang berkaitan dengan hak kepemilikan. Sebagai akibat adanya sertifikat hak atas tanah yang telah diterbitkan oleh dua pemerintahan yang berbeda dapat menimbulkan persoalan-persoalan di masyarakat setelah kemerdekaannya. Oleh karena itu pemerintah Timor Leste segera merumuskan suatu kebijakan yang dimanifestasikan dalam bentuk undang-undang yang selanjutnya dikenal dengan UU No.1/2003. Pemberlakuan UU No.1/2003 ini pada dasarnya mengatur 3 ketentuan hukum prioritas: pertama, kepentingan umum (negara); kedua, kepentingan bekas pemegang hak, dan; ketiga pemanfaatkan tanah atau bangunan oleh masyarakat. metode penelitian yang digunakan dalam penelitian ini bersifat deskriptif dengan menggunakan pendekatan kualitatif. DNTPSC sebagai badan pelaksana telah memaksimalkan seluruh unit kerja yang ada di struktur baik di tingkat pusat maupun daerah. Dalam Implementasi kebijakan pemerintah ini dengan kontribusi yang signifikan dari berbagai pihak. Hasil temuan dalam penelitian menunjukkan telah terdaftarnya 12943 pengaduan atau klaim dengan pemanfaatannya sebesar 11343 sedangkan 1927 sebagai Asset Milik Negara (AMN) telah dimanfaatkan secara maksimal. Implementasi kebijakan nasionalisasi telah mencapai target, hal ini tidak terlepas dari koordinasi antar institusi pemerintah yang baik, adanya aturan hukum yang jelas, dukungan donator Internasional, partisipasi masyarakat dan sarana prasarana. Kata Kunci: Evaluasi Kebijakan, Nasionalisas

Dispersive Optical Interface Based on Nanofiber-Trapped Atoms

We dispersively interface an ensemble of one thousand atoms trapped in the evanescent field surrounding a tapered optical nanofiber. This method relies on the azimuthally-asymmetric coupling of the ensemble with the evanescent field of an off-resonant probe beam, transmitted through the nanofiber. The resulting birefringence and dispersion are significant; we observe a phase shift per atom of $\sim$\,1\,mrad at a detuning of six times the natural linewidth, corresponding to an effective resonant optical density per atom of 0.027. Moreover, we utilize this strong dispersion to non-destructively determine the number of atoms.Comment: 4 pages, 4 figure

Entangled-Photon Imaging of a Pure Phase Object

We demonstrate experimentally and theoretically that a coherent image of a pure phase object may be obtained by use of a spatially incoherent illumination beam. This is accomplished by employing a two-beam source of entangled photons generated by spontaneous parametric down-conversion. Though each of the beams is, in and of itself, spatially incoherent, the pair of beams exhibits higher-order inter-beam coherence. One of the beams probes the phase object while the other is scanned. The image is recorded by measuring the photon coincidence rate using a photon-counting detector in each beam. Using a reflection configuration, we successfully imaged a phase object implemented by a MEMS micro-mirror array. The experimental results are in accord with theoretical predictions.Comment: 11 pages, 3 figures, submittedto Phys. Rev. Let