Cesium‐vapor‐based delay of single photons emitted by deterministically fabricated quantum dot microlenses

Quantum light sources are key building blocks of photonic quantum technologies. For many applications, it is of interest to control the arrival time of single photons emitted by such quantum devices, or even to store single photons in quantum memories. In situ electron beam lithography is applied to realize InGaAs quantum dot (QD)‐based single‐photon sources, which are interfaced with cesium (Cs) vapor to control the time delay of emitted photons. Via numerical simulations of the light–matter interaction in realistic QD‐Cs‐vapor configurations, the influence of the vapor temperature and spectral QD‐atom detuning is explored to maximize the achievable delay in experimental studies. As a result, this hybrid quantum system allows to trigger the emission of single photons with a linewidth as low as 1.54 GHz even under non‐resonant optical excitation and to delay the emission pulses by up to (15.71 ± 0.01) ns for an effective cell length of 150 mm. This work can pave the way for scalable quantum systems relying on a well‐controlled delay of single photons on a time scale of up to a few tens of nanoseconds.BMBF, 03V0630TIB, Entwicklung einer Halbleiterbasierten Einzelphotonenquelle für die QuanteninformationstechnologieBMBF, 13N14876, Quantenkommunikations-Systeme auf Basis von Einzelphotonenquellen (QuSecure)DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, BauelementeTU Berlin, Open-Access-Mittel - 201

The Krull dimension of power series rings over non-SFT rings

AbstractLet R be a commutative ring with identity. We show that the Krull dimension of the power series ring R〚X〛 can be uncountably infinite, i.e., there exists an uncountably infinite chain of prime ideals in R〚X〛, even if dimR is finite. In fact, we show that dimR〚X〛 is uncountably infinite if R is a non-SFT ring, which is an improvement of Arnold’s result

Functional muscle hypertrophy by increased insulin-like growth factor 1 does not require dysferlin.

IntroductionDysferlin loss-of-function mutations cause muscular dystrophy, accompanied by impaired membrane repair and muscle weakness. Growth promoting strategies including insulin-like growth factor 1 (IGF-1) could provide benefit but may cause strength loss or be ineffective. The objective of this study was to determine whether locally increased IGF-1 promotes functional muscle hypertrophy in dysferlin-null (Dysf-/- ) mice.MethodsMuscle-specific transgenic expression and postnatal viral delivery of Igf1 were used in Dysf-/- and control mice. Increased IGF-1 levels were confirmed by enzyme-linked immunosorbent assay. Testing for skeletal muscle mass and function was performed in male and female mice.ResultsMuscle hypertrophy occurred in response to increased IGF-1 in mice with and without dysferlin. Male mice showed a more robust response compared with females. Increased IGF-1 did not cause loss of force per cross-sectional area in Dysf-/- muscles.DiscussionWe conclude that increased local IGF-1 promotes functional hypertrophy when dysferlin is absent and reestablishes IGF-1 as a potential therapeutic for dysferlinopathies

0-7030: Synthesis of Engineered Cementitious Composites (ECC) for Applications in Texas

Engineered cementitious composites (ECC) are a special type of high-performance fiber-reinforced cementitious composites that is characterized by high-ductility (3–5% strain) and moderate tensile strength (4–6 MPa) with 1.5–2% fiber content by volume. Under tensile deformation, ECC shows strain-hardening behavior and closely spaced microcracks after the first cracking. ECC possesses excellent shear capacity, improved damage tolerance, ability to control crack width, and synergistic interaction with reinforcing bars. ECC has been proposed as a novel alternative for infrastructure materials but to date has not seen wide application in Texas or the rest of the United States. The objective of this project is to identify high priority applications of ECC appropriate to the Texas transportation system

Proteomic Analysis to Identify Tightly-Bound Cell Wall Protein in Rice Calli.

Rice is a model plant widely used for basic and applied research programs. Plant cell wall proteins play key roles in a broad range of biological processes. However, presently, knowledge on the rice cell wall proteome is rudimentary in nature. In the present study, the tightly-bound cell wall proteome of rice callus cultured cells using sequential extraction protocols was developed using mass spectrometry and bioinformatics methods, leading to the identification of 1568 candidate proteins. Based on bioinformatics analyses, 389 classical rice cell wall proteins, possessing a signal peptide, and 334 putative non-classical cell wall proteins, lacking a signal peptide, were identified. By combining previously established rice cell wall protein databases with current data for the classical rice cell wall proteins, a comprehensive rice cell wall proteome, comprised of 496 proteins, was constructed. A comparative analysis of the rice and Arabidopsis cell wall proteomes revealed a high level of homology, suggesting a predominant conservation between monocot and eudicot cell wall proteins. This study importantly increased information on cell wall proteins, which serves for future functional analyses of these identified rice cell wall proteins

Compton Scattering on the Deuteron in Baryon Chiral Perturbation Theory

Compton scattering on the deuteron is studied in the framework of baryon chiral perturbation theory to third order in small momenta, for photon energies of order the pion mass. The scattering amplitude is a sum of one- and two-nucleon mechanisms with no undetermined parameters. Our results are in good agreement with existing experimental data, and a prediction is made for higher-energy data being analyzed at SAL.Comment: 39 pages LaTeX, 19 figures (uses epsf

A Hybrid Si-SiC Flyback Converter for Auxiliary Power Supplies in DC Ship Grids

In this paper, a flyback converter-derived two-switch topology is proposed for use in auxiliary power supplies for dc shipgrids. TheSi-SiC hybrid converter offers a low-cost solution compared to the conventional two-switch flyback (TSF) topology for high step-down dc/dc converters. Through the introduction of additional circuitry, the voltage stress on the semiconductors is alleviated, thereby enabling the use of cheaper semiconductor devices.The design of the converter, its steady-state operation, and a performance comparison with the conventional TSF converter are presented in this paper through an analytical study. Moreover, an experimental prototype of a 1500 V input to 24V output power supply is developed to validate the operation of the topology

Nucleon-Nucleon Effective Field Theory Without Pions

Nuclear processes involving momenta much below the mass of the pion may be described by an effective field theory in which the pions do not appear as explicit degrees of freedom. The effects of the pion and all other virtual hadrons are reproduced by the coefficients of gauge-invariant local operators involving the nucleon field. Nucleon-nucleon scattering phase shift data constrains many of the coefficients that appear in the effective Lagrangean but at some order in the expansion coefficients enter that must be constrained by other observables. We compute several observables in the two-nucleon sector up to next-to-next-to leading order in the effective field theory without pions, or to the order at which a counterterm involving four-nucleon field operators is encountered. Effective range theory is recovered from the effective field theory up to the order where relativistic corrections enter or where four-nucleon-external current local operators arise. For the deuteron magnetic moment, quadrupole moment and the $np\to d\gamma$ radiative capture cross section a four-nucleon-one-photon counterterm exists at next-to-leading order. The electric polarizability and electric charge form factor of the deuteron are determined up to next-to-next-to-leading order, which includes the first appearance of relativistic corrections.Comment: 27 pages, 8 figures, latex. SD-mixing, quadrupole moment modifie

The Polarizability of the Deuteron

The scalar and tensor polarizabilities of the deuteron are calculated using the recently developed effective field theory that describes nucleon-nucleon interactions. Leading and next-to-leading order contributions in the perturbative expansion predict a scalar electric polarizability of 0.595 fm^3. The tensor electric polarizability receives contributions starting at next-to-leading order from the exchange of a single potential pion and is found to be -0.062 fm^3. We compute the leading contributions to the scalar and tensor magnetic polarizabilities, finding 0.067 fm^3 and 0.195 fm^3, respectively.Comment: 13 pages, 4 figures as 6 eps files, latex. References adde