9:00 
Welcome Adresses
Jürgen P. Rabe (Direktor IRIS Adlershof, HumboldtUniversität zu Berlin)
Peter A. Frensch (Vizepräsident für Forschung, HumboldtUniversität zu Berlin)
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9:20 
Sub 100 meV electron energy loss spectroscopy in the scanning transmission electron microscope  from phonons to core losses in real and momentum space
Quentin Ramasse (SuperSTEM Laboratory and University of Leeds, U.K.)
The properties of materials are increasingly controlled and tuned through defects engineering taking place quite literally at the atomic level, where one of the most powerful means of characterization arguably lies within a combination of low voltage scanning transmission electron microscopy, energy loss spectroscopy and ab initio calculations. Recent instrumentation advances have pushed the spatial resolution of these instruments below 1Å, while providing energy resolution for spectroscopy of <10meV. This contribution will highlight a number of applications of these techniques, including a recentlydeveloped methodology for recoding momentumresolved energy loss spectra at nm resolution.
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10:00 
Nanoscale 3D Xray tomography and spectromicroscopy
Gerd Schneider (HelmholtzZentrum Berlin für Materialien und Energie & HumboldtUniversität zu Berlin)
In the nanoage, humans manufacture complex structures atom by atom to design e.g. their specific functionality. Therefore, new tools for the analysis of these structures have to be developed. The HZB microscopy group develops novel methods for Xray imaging to make use out of the unique interactions of Xrays with matter. For this, Xray optics for the 10nm scale characterization of the nanostructure, chemical nature, and composition of materials with high energy resolution are engineered and fabricated. The HZB fullfield TXM at the BESSY II U41 undulator beamline allows high spectral resolution of E/ΔE=5000 and 10 nm spatial resolution. With this instrument spatiallyresolved NEXAFS studies for material sciences can be performed due to the high energy resolution. Additionally, nanotomography of cryogenic samples had demonstrated its high potential for life sciences.
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10:25 
Multiscale characterization in materials science – travelling in space and time
Michael Rauscher, Tobias Volkenandt (Carl Zeiss Microscopy GmbH, Oberkochen)
For the large spectrum of engineering materials from battery electrodes to fiber composites to metal alloys, there exist features from the nanometer scale up to mm and larger which play unique and distinct roles in determining the functionality of that material or device. Central to understanding these multiscale features are a variety of experimental characterization methods, of which microscopy plays a key role. In this talk we will introduce recent advances in microscopy techniques by means of selected case studies.
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10:50 
Coffee break

11:15 
2D or not 2D? Metalfree nanomaterials beyond graphene
Michael J. Bojdys (HumboldtUniversität zu Berlin)
There is a lack of crystalline, metalfree 2Dmaterials “beyond graphene (BEG)” for the construction of electronic devices. Such BEGmaterials are highly desirable, because todate no useful narrow bandgap semiconductors exist that would bridge the gap between wide bandgap transition metal dichalcogenides (TMD) that rely on critical raw materials (CRMs) and metallic graphene. To tackle this fundamental designproblem, we are drawing on our previous, successful synthesis of lowbandgap semiconducting 2D polymers obtained via “ontemplate” and “oncatalyst” synthesis (e.g. Angew. Chem. Int. Ed. 2014, 53, 7450 and Adv. Mater. 2017, 29, 1703399).
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11:45 
Quantum dots as a new class of hybrid materials for optoelectronic applications
Armin Wedel (Fraunhofer IAP Potsdam)
Quantum dots (QDs) can provide unique properties such as sizedependent bandgap tunability, narrow emission spectrum, and lowcost solutionbased processing. Through these unique advantages, hybrid organic/inorganic QD lightemitting diodes (QDLEDs) have attracted considerable attention in display and lighting industry. Currently, a major future task in the device development is to substitute Cdcontaining QDs with less toxic materials such as InPbased IIIV semiconductor. One of the most challenging works in fabricating multilayer QDLEDs using colloidal QD solution are the combination with charge transport materials.
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12:10 
Dynamic properties of metalhalide perovskites relevant for optoelectronic devices
Eva Unger (HelmholtzZentrum Berlin für Materialien und Energie & HumboldtUniversität zu Berlin)
Metalhalide perovskite semiconductors are an intriguing class of new semiconducting materials for energy conversion technology. Their low enthalpy of formation provides many possibilities to process these materials from solution but chemical reactions induced by light, heat, atmospheric molecules and ion migration cause dynamic and transient phenomena on various different time scales that need to be understood to reliably predict the potential of this emerging material class. This talk will highlight transient phenomena in metalhalide perovskite materials and devices from currentvoltage hysteresis to photoinduced phasesegregation and degradation.
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12:45 
Lunch break

13:45 
Hyperbolic tilings in soft matter physics
Myfanwy Evans (Technische Universität Berlin)
Twodimensional surfaces provide a natural way to study threedimensional structure, think of buckyballs on a sphere and carbon nanotubes on a cylinder. Taking the lead from selfassembly processes in biology, twodimensional hyperbolic minimal surfaces can be used as a scaffold for more complicated spatial geometry. This talk will introduce the idea of using hyperbolic tilings as a precursor to tangled threedimensional nets and weavings, followed by an interesting case of hyperbolic self assembly in star terpolymer simulations.
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14:15 
Irreversible Markov chains in statistical physics
Werner Krauth (Ecole Normale Superieure Paris & MPI für Physik komplexer Systeme)
Virtually all current Monte Carlo algorithms are rooted in the detailedbalance condition, that implements reversible stochastic dynamics. But there is much more to Monte Carlo than detailed balance and the Metropolis/Heatbath paradigm. Indeed, irreversible Markov chains can be conceived very generally for cases ranging from hardsphere models (in 1D, they are related to the TASEP) to longrangeinteracting particle systems. In the new irreversible sampling framework, thermodynamic equilibrium is often reached on much faster timescales than with reversible algorithms (finite probability flows persist up to infinite times), the system potential is factorized, the Metropolis acceptance is replaced by a consensus rule, and the system energy is never computed.
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14:45 
Elements of a topological quantum computer
Felix von Oppen (Freie Universität Berlin)
Quantum computers need to maintain quantum coherence of quantum bits over long times, requiring nearperfect decoupling from the environment. Topological quantum computation provides a remarkable and promising route towards this goal. In its hardware incarnation, quantum information is encoded in qubits built on (nonabelian) anyonicexcitations of topological phases and quantum information processing relies on nontrivial behavior of these anyonsunder exchange (braiding). There is currently growing optimism in both academia and industry that the simplest such topological qubit – based on Majoranabound states – can be realized and perhaps even be developed into a topological quantum computer. This talk will describe essential elements of such a topological quantum computer, covering the range from Majoranabased qubits to the implementation of a universal set of quantum gates. The hardware approach can be further enhanced to realize faulttolerant quantum computation by adding topological quantum error correction, a softwarebased approach to topological quantum computation which can be seamlessly matched with the topological hardware.
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15:15 
Poster Session

16:30 
Nonreciprocal quantum optical devices based on chiral interaction of confined light with spinpolarized atoms
Arno Rauschenbeutel (HumboldtUniversität zu Berlin & Technische Universität Wien)
The confinement of light in nanophotonic structures results in an inherent link between the light’s local polarization and its propagation direction. Remarkably, this leads to chiral, i.e., propagationdirectiondependent effects in the emission and absorption of light by quantum emitters. We employed this effect to demonstrate an integrated optical isolator as well as an integrated optical circulator which operate at the singlephoton level and which exhibit low loss. These are the first two examples of a new class of nonreciprocal nanophotonic devices which exploit the chiral interaction of quantum emitters with transversally confined photons.
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17:10 
Quantum state tomography in low dimensional semiconductor optoelectronic devices
Ulrike Woggon (Technische Universität Berlin)
Quantum state tomography (QST) is a technique to reconstruct the full quantum state from the statistical measurement of the field fluctuations. Combination of QST with a pumpprobe setup allows us to directly manipulate the quantum state on a subpicosecond timescale. QST is applied to InGaAs quantum dotsemiconductor optical amplifiers (QDSOA) to retrieve the Wigner function and the photon statistics for a coherent state interacting with QDs with high timeresolution and in the fewemitter limit. We can reconstruct the second order autocorrelation function with higher precision and time resolution compared with classical Hanbury BrownTwiss experiments.
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17:35 
Single photon counting in optical quantum technologies
Andreas Bülter, Michael Wahl (PicoQuant GmbH, Berlin)
Photon coincidence detection, coincidence correlation and coincidence counting are fundamental methods in optical quantum technologies. Typical examples are HanburyBrownTwiss setups to study single photon sources, quantum communication and quantum key distribution (QKD), the study of entanglement using HongOu Mandel (HOM) setups or Bell state measurements. For all these applications single photon counting is an ideal tool, since this method records absolute signal arrival times on several detection channels in parallel. The presentation will review the basics of single photon counting and their technical realisation and will give some typical application examples.
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18:00 
Barbecue
Gerdans Cafe
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