Accurate measurement of a 96% input coupling into a cavity using polarization tomography

Pillar microcavities are excellent light-matter interfaces providing an electromagnetic confinement in small mode volumes with high quality factors. They also allow the efficient injection and extraction of photons, into and from the cavity, with potentially near-unity input and output-coupling efficiencies. Optimizing the input and output coupling is essential, in particular, in the development of solid-state quantum networks where artificial atoms are manipulated with single incoming photons. Here we propose a technique to accurately measure input and output coupling efficiencies using polarization tomography of the light reflected by the cavity. We use the residual birefringence of pillar microcavities to distinguish the light coupled to the cavity from the uncoupled light: the former participates to rotating the polarization of the reflected beam, while the latter decreases the polarization purity. Applying this technique to a micropillar cavity, we measure a $53 \pm2 \%$ output coupling and a $96 \pm 1\%$ input coupling with unprecedented precision.Comment: 6 pages, 3 figure

D-branes in Topological Minimal Models: the Landau-Ginzburg Approach

We study D-branes in topologically twisted N=2 minimal models using the Landau-Ginzburg realization. In the cases of A and D-type minimal models we provide what we believe is an exhaustive list of topological branes and compute the corresponding boundary OPE algebras as well as all disk correlators. We also construct examples of topological branes in E-type minimal models. We compare our results with the boundary state formalism, where possible, and find agreement.Comment: 29 pages, late

Generating Function for Particle-Number Probability Distribution in Directed Percolation

We derive a generic expression for the generating function (GF) of the particle-number probability distribution (PNPD) for a simple reaction diffusion model that belongs to the directed percolation universality class. Starting with a single particle on a lattice, we show that the GF of the PNPD can be written as an infinite series of cumulants taken at zero momentum. This series can be summed up into a complete form at the level of a mean-field approximation. Using the renormalization group techniques, we determine logarithmic corrections for the GF at the upper critical dimension. We also find the critical scaling form for the PNPD and check its universality numerically in one dimension. The critical scaling function is found to be universal up to two non-universal metric factors.Comment: (v1,2) 8 pages, 5 figures; one-loop calculation corrected in response to criticism received from Hans-Karl Janssen, (v3) content as publishe

Peranan Pompa Proton pada Pertumbuhan Escherichia coli di Lingkungan pH Alkali

Pompa proton, yang dapat diaktifkan oleh senyawa gula, diketahui terlibat dalam adaptasi pH rendah di berbagai bakteri. Kami telah mengkonfirmasi sebelumnya bahwa E. coli juga dikenal menggunakan pompa untuk adaptasinya pada pH rendah. Namun demikian, masih harus dikonfirmasi apakah pertumbuhan E. coli pada pH basa juga melibatkan mekanisme yang sama, dimana pompa terlibat. Penelitian ini bertujuan untuk menganalisis pertumbuhan E. coli dalam media Luria-Bertani (LB) pada pH basa dan berbagai konsentrasi glukosa sebagai aktivator untuk pompa proton. Metode yang digunakan dalam penelitian ini adalah rancangan acak lengkap pola faktorial, dimana bakteri ditanam dalam kaldu Luria-Bertani (LB) dengan kondisi yang berbeda. Kurva pertumbuhan diukur menggunakan absorbansi UV-vis pada 600 nm dan dianalisis secara deskriptif. Hasil penelitian menunjukkan bahwa pH pada media sangat mempengaruhi tingkat pertumbuhan bakteri E. coli. Secara umum, E. coli yang ditanam di media dengan pH 12 membutuhkan fase lag yang lebih lama dibandingkan dengan E. coli yang ditanam di media dengan pH 7. Penambahan glukosa pada konsentrasi 5% mampu meningkatkan laju pertumbuhan E. coli di kedua media dengan pH 7 dan 12. Kesimpulan dari penelitian ini adalah stres lingkungan karena peningkatan pH media dapat memperlambat laju pertumbuhan bakteri E. coli, dimana penambahan 5% glukosa dapat membantu meningkatkan tingkat pertumbuhan E. coli. Secara keseluruhan, glukosa ditemukan tidak memiliki efek serius pada pertumbuhan E. coli pada pH basa yang menunjukkan bahwa keterlibatan pompa proton untuk adaptasi pada pH basa adalah minimum

Engineering the Level Structure of a Giant Artificial Atom in Waveguide Quantum Electrodynamics

Engineering light-matter interactions at the quantum level has been central to the pursuit of quantum optics for decades. Traditionally, this has been done by coupling emitters, typically natural atoms and ions, to quantized electromagnetic fields in optical and microwave cavities. In these systems, the emitter is approximated as an idealized dipole, as its physical size is orders of magnitude smaller than the wavelength of light. Recently, artificial atoms made from superconducting circuits have enabled new frontiers in light-matter coupling, including the study of "giant" atoms which cannot be approximated as simple dipoles. Here, we explore a new implementation of a giant artificial atom, formed from a transmon qubit coupled to propagating microwaves at multiple points along an open transmission line. The nature of this coupling allows the qubit radiation field to interfere with itself leading to some striking giant-atom effects. For instance, we observe strong frequency-dependent couplings of the qubit energy levels to the electromagnetic modes of the transmission line. Combined with the ability to in situ tune the qubit energy levels, we show that we can modify the relative coupling rates of multiple qubit transitions by more than an order of magnitude. By doing so, we engineer a metastable excited state, allowing us to operate the giant transmon as an effective lambda system where we clearly demonstrate electromagnetically induced transparency.Comment: 12 pages, 8 figure

Dynamics and Excitation of Radio Galaxy Emission-Line Regions - I. PKS 2356-61

Results are presented from a programme of detailed longslit spectroscopic observations of the extended emission-line region (EELR) associated with the powerful radio galaxy PKS 2356-61. The observations have been used to construct spectroscopic datacubes, which yield detailed information on the spatial variations of emission-line ratios across the EELR, together with its kinematic structure. We present an extensive comparison between the data and results obtained from the MAPPINGS II shock ionization code, and show that the physical properties of the line-emitting gas, including its ionization, excitation, dynamics and overall energy budget, are entirely consistent with a scenario involving auto-ionizing shocks as the dominant ionization mechanism. This has the advantage of accounting for the observed EELR properties by means of a single physical process, thereby requiring less free parameters than the alternative scheme involving photoionization by radiation from the active nucleus. Finally, possible mechanisms of shock formation are considered in the context of the dynamics and origin of the gas, specifically scenarios involving infall or accretion of gas during an interaction between the host radio galaxy and a companion galaxy.Comment: 35 pages, LaTeX, uses aas2pp4.sty file, includes 9 PostScript figures. Two additional colour plates are available from the authors upon request. Accepted for publication in the Astrophysical Journa