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 -