TY - JOUR AB - Employing the ultrafast control of electronic states of a semiconductor quantum dot in a cavity, we introduce an approach to achieve on-demand emission of single photons with almost perfect indistinguishability and photon pairs with near ideal entanglement. Our scheme is based on optical excitation off resonant to a cavity mode followed by ultrafast control of the electronic states using the time-dependent quantum-confined Stark effect, which then allows for cavity-resonant emission. Our theoretical analysis considers cavity-loss mechanisms, the Stark effect, and phonon-induced dephasing, allowing realistic predictions for finite temperatures. AU - Bauch, David AU - Heinze, Dirk Florian AU - Förstner, Jens AU - Jöns, Klaus AU - Schumacher, Stefan ID - 23816 JF - Physical Review B KW - tet_topic_qd SN - 2469-9950 TI - Ultrafast electric control of cavity mediated single-photon and photon-pair generation with semiconductor quantum dots VL - 104 ER - TY - JOUR AB - AbstractA detailed investigation of the energy levels of perylene-3,4,9,10-tetracarboxylic tetraethylester as a representative compound for the whole family of perylene esters was performed. It was revealed via electrochemical measurements that one oxidation and two reductions take place. The bandgaps determined via the electrochemical approach are in good agreement with the optical bandgap obtained from the absorption spectra via a Tauc plot. In addition, absorption spectra in dependence of the electrochemical potential were the basis for extensive quantum-chemical calculations of the neutral, monoanionic, and dianionic molecules. For this purpose, calculations based on density functional theory were compared with post-Hartree–Fock methods and the CAM-B3LYP functional proved to be the most reliable choice for the calculation of absorption spectra. Furthermore, spectral features found experimentally could be reproduced with vibronic calculations and allowed to understand their origins. In particular, the two lowest energy absorption bands of the anion are not caused by absorption of two distinct electronic states, which might have been expected from vertical excitation calculations, but both states exhibit a strong vibronic progression resulting in contributions to both bands. AU - Wiebeler, Christian AU - Vollbrecht, Joachim AU - Neuba, Adam AU - Kitzerow, Heinz-Siegfried AU - Schumacher, Stefan ID - 39653 IS - 1 JF - Scientific Reports KW - Multidisciplinary SN - 2045-2322 TI - Unraveling the electrochemical and spectroscopic properties of neutral and negatively charged perylene tetraethylesters VL - 11 ER - TY - JOUR AU - Klement, Philip AU - Dehnhardt, Natalie AU - Dong, Chuan-Ding AU - Dobener, Florian AU - Bayliff, Samuel AU - Winkler, Julius AU - Hofmann, Detlev M. AU - Klar, Peter J. AU - Schumacher, Stefan AU - Chatterjee, Sangam AU - Heine, Johanna ID - 40434 IS - 23 JF - Advanced Materials KW - Mechanical Engineering KW - Mechanics of Materials KW - General Materials Science SN - 0935-9648 TI - Atomically Thin Sheets of Lead‐Free 1D Hybrid Perovskites Feature Tunable White‐Light Emission from Self‐Trapped Excitons VL - 33 ER - TY - JOUR AU - Barkhausen, Franziska AU - Pukrop, Matthias AU - Schumacher, Stefan AU - Ma, Xuekai ID - 21359 IS - 7 JF - Physical Review B SN - 2469-9950 TI - Structuring coflowing and counterflowing currents of polariton condensates in concentric ring-shaped and elliptical potentials VL - 103 ER - TY - JOUR AU - Franz, Martin AU - Chandola, Sandhya AU - Koy, Maximilian AU - Zielinski, Robert AU - Aldahhak, Hazem AU - Das, Mowpriya AU - Freitag, Matthias AU - Gerstmann, Uwe AU - Liebig, Denise AU - Hoffmann, Adrian Karl AU - Rosin, Maximilian AU - Schmidt, Wolf Gero AU - Hogan, Conor AU - Glorius, Frank AU - Esser, Norbert AU - Dähne, Mario ID - 24975 JF - Nature Chemistry SN - 1755-4330 TI - Controlled growth of ordered monolayers of N-heterocyclic carbenes on silicon ER - TY - JOUR AB - Density-functional theory within a Berry-phase formulation of the dynamical polarization is used to determine the second-order susceptibility χ(2) of lithium niobate (LiNbO3). Defect trapped polarons and bipolarons are found to strongly enhance the nonlinear susceptibility of the material, in particular if localized at NbV–VLi defect pairs. This is essentially a consequence of the polaronic excitation resulting in relaxation-induced gap states. The occupation of these levels leads to strongly enhanced χ(2) coefficients and allows for the spatial and transient modification of the second-harmonic generation of macroscopic samples. AU - Kozub, Agnieszka L. AU - Schindlmayr, Arno AU - Gerstmann, Uwe AU - Schmidt, Wolf Gero ID - 23418 JF - Physical Review B SN - 2469-9950 TI - Polaronic enhancement of second-harmonic generation in lithium niobate VL - 104 ER - TY - CONF AU - Rose, Hendrik AU - Paul, Jagannath AU - Wahlstrand, Jared K. AU - Bristow, Alan D. AU - Meier, Torsten ED - Betz, Markus ED - Elezzabi, Abdulhakem Y. ID - 23475 T2 - Ultrafast Phenomena and Nanophotonics XXV TI - Theoretical analysis and simulations of two-dimensional Fourier transform spectroscopy performed on exciton-polaritons of a quantum-well microcavity system VL - 11684 ER - TY - JOUR AU - Krauss-Kodytek, L. AU - Hannes, W.-R. AU - Meier, Torsten AU - Ruppert, C. AU - Betz, M. ID - 37333 IS - 8 JF - Physical Review B SN - 2469-9950 TI - Nondegenerate two-photon absorption in ZnSe: Experiment and theory VL - 104 ER - TY - JOUR AU - Riabinin, Matvei AU - Sharapova, Polina AU - Bartley, Tim AU - Meier, Torsten ID - 21547 IS - 4 JF - Journal of Physics Communications SN - 2399-6528 TI - Generating two-mode squeezing with multimode measurement-induced nonlinearity VL - 5 ER - TY - JOUR AU - Krauss-Kodytek, L. AU - Hannes, Wolf-Rüdiger AU - Meier, Torsten AU - Ruppert, C. AU - Betz, M. ID - 23472 IS - 8 JF - Physical Review B SN - 2469-9950 TI - Nondegenerate two-photon absorption in ZnSe: Experiment and theory VL - 104 ER - TY - CONF AU - Moritzer, Elmar AU - Flachmann, Felix ID - 26390 T2 - PPS-36 Proceedings TI - Process-reliable Injection Molding of Highly Filled Wood-Plastic-Composites (WPC) ER - TY - JOUR AU - Teichert, Jeannine ID - 44200 IS - 1 JF - Networking Knowledge TI - Mediating close friendship intimacy in times of (social) distance VL - 14 ER - TY - JOUR AU - Grabo, Matti AU - Acar, Emre AU - Kenig, Eugeny ID - 22265 JF - Renewable Energy SN - 0960-1481 TI - Modeling and improvement of a packed bed latent heat storage filled with non-spherical encapsulated PCM-Elements VL - 173 ER - TY - CONF AU - Rostek, Tim AU - Makeieva, Hanna AU - Homberg, Werner ED - Daehn, G. ED - Cao, J. ED - Kinsey, B. ED - Tekkaya, A. E. ED - Vivek, A. ED - Yoshida, Y ID - 21477 SN - 978-3-030-75380-1 T2 - Proceedings of the 13th International Conference on the Technology of Plasticity TI - Cutting Blades for Food Processing Applications Manufactured Using Innovative Spin Forming ER - TY - JOUR AB - The predictive quality of numerical simulations for mechanical joining processes depends on the implemented material model, especially regarding the plasticity of the joining parts. Therefore, experimental material characterization processes are conducted to determine the material properties of sheet metal and generate flow curves. In this regard, there are a number of procedures which are accompanied by varying experimental efforts. This paper presents various methods of determining flow curves for HCT590X as well as EN AW-6014, including varying specimen geometries and diverse hardening laws for extrapolation procedures. The flow curves thus generated are compared considering the variety of plastic strains occurring in mechanical joining processes. The material data generated are implemented in simulation models for the joining technologies, clinching and self-piercing riveting. The influence of the varied methods on the predictive accuracy of the simulation model is analysed. The evaluation of the differing flow curves is achieved by comparing the geometric formation of the joints and the required joining forces of the processes with experimentally investigated joints. AU - Böhnke, Max AU - Kappe, Fabian AU - Bobbert, Mathias AU - Meschut, Gerson ID - 22798 IS - 6 JF - Materials Testing SN - 2195-8572 TI - Influence of various procedures for the determination of flow curves on the predictive accuracy of numerical simulations for mechanical joining processes VL - 63 ER - TY - JOUR AB - The increasing use of multi-material constructions lead to a continuous increase in the use of mechanical joining techniques due to the wide range of joining possibilities as well as the high load-bearing capacities of the joints. Nevertheless, the currently rigid tool systems are not able to react to changing boundary conditions, like changing the material-geometry-combination. Therefore research work is crucial with regard to versatile joining systems. In this paper, a new approach for a versatile self-piercing riveting process considering the joining system as well as the auxiliary joining part is presented. AU - Kappe, Fabian AU - Bobbert, Mathias AU - Meschut, Gerson ID - 34226 JF - Key Engineering Materials KW - Mechanical Engineering KW - Mechanics of Materials KW - General Materials Science SN - 1662-9795 TI - New Approach for Versatile Self Piercing Riveting: Joining System and Auxiliary Part VL - 883 ER - TY - JOUR AU - Wituschek, Simon AU - Kappe, Fabian AU - Lechner, Michael ID - 30200 JF - Production Engineering TI - Investigation of the influence of varying tumbling strategies on a tumbling self-piercing riveting process ER - TY - CHAP AU - Dahms, Frederik AU - Homberg, Werner ID - 22766 SN - 2367-1181 T2 - Forming the Future TI - Investigations and Improvements in 3D-DIC Optical Residual Stress Analysis—A New Temperature Compensation Method ER - TY - JOUR AB - The increase of the thermal conductivity of PUR foam in the insulation of the cabinet is an important cause for aging processes of household refrigerating appliances. To determine the influence of the PUR foam aging on energy consumption, the development of a new measurement method is necessary be- cause current methods influence the aging behavior of household refrigerators and are therefore not applicable in general. Based on a latent heat sink, constructed as an ice water bucket, a new measure- ment method is developed to determine the k ·A value over time. With this method, the k ·A value of four household refrigerating appliances was determined over an interval of 14 months. The k ·A value increased between 3.6% and 11.5% during this period. AU - Paul, Andreas AU - Baumhögger, Elmar AU - Elsner, Andreas AU - Moczarski, Lukas AU - Reineke, Michael AU - Sonnenrein, Gerrit AU - Hueppe, Christian AU - Stamminger, Rainer AU - Hoelscher, Heike AU - Wagner, Hendrik AU - Gries, Ulrich AU - Freiberger, Alfred AU - Becker, Wolfgang AU - Vrabec, Jadran ID - 20921 JF - International Journal of Refrigeration SN - 0140-7007 TI - Determining the heat flow through the cabinet walls of household refrigerating appliances ER - TY - JOUR AB - Domestic refrigeration appliances are standard household commodities. Although policies, such as the energy labelling, prompted technical improvements and decreased appliance energy consumption throughout recent decades, important parameters were disregarded. These refer to the efficiency loss over time and the consumer behaviour. The objective of this contribution was to develop a dynamic energy model to determine the power consumption of refrigeration appliances considering degradation factors and behaviour. These were included by model parameters for direct consumer interactions, such as the storage behaviour, door openings and temperature setting, as well as indirect actions, e.g. exposing an appliance to specific temperature conditions at an installation site. For this, an online-survey was conducted to evaluate the consumer behaviour. A total of 706 consumers participated in the national questionnaire, serving as input for the dynamic energy model. It was found that the efficiency loss increases the power consumption by at least 1% annually, leading to an excess of 10% after 10 years of usage. Another important finding was that 32.5% of appliance’s power consumption results from consumer behaviour, whereas the promotion of behavioural changes leads to a significant decrease of the consumer-induced consumption. Consequently, this study provides a tool to evaluate the impact of policies targeting refrigeration appliances, stressing that efficiency loss and behaviour should be integrated into future policy approaches. AU - Hueppe, Christian AU - Geppert, Jasmin AU - Moenninghoff-Juessen, Julia AU - Wolff, Lena AU - Stamminger, Rainer AU - Paul, Andreas AU - Elsner, Andreas AU - Vrabec, Jadran AU - Wagner, Hendrik AU - Hoelscher, Heike AU - Becker, Wolfgang AU - Gries, Ulrich AU - Freiberger, Alfred ID - 27290 JF - Energy Policy SN - 0301-4215 TI - Investigating the real life energy consumption of refrigeration appliances in Germany: Are present policies sufficient? ER -