Ordered Measurements of Permutationally-Symmetric Qubit Strings

We show that any sequence of measurements on a permutationally-symmetric (pure or mixed) multi-qubit string leaves the unmeasured qubit substring also permutationally-symmetric. In addition, we show that the measurement probabilities for an arbitrary sequence of single-qubit measurements are independent of how many unmeasured qubits have been lost prior to the measurement. Our results are valuable for quantum information processing of indistinguishable particles by post-selection, e.g. in cases where the results of an experiment are discarded conditioned upon the occurrence of a given event such as particle loss. Furthermore, our results are important for the design of adaptive-measurement strategies, e.g. a series of measurements where for each measurement instance, the measurement basis is chosen depending on prior measurement results.Comment: 13 page

Batch Reinforcement Learning on the Industrial Benchmark: First Experiences

The Particle Swarm Optimization Policy (PSO-P) has been recently introduced and proven to produce remarkable results on interacting with academic reinforcement learning benchmarks in an off-policy, batch-based setting. To further investigate the properties and feasibility on real-world applications, this paper investigates PSO-P on the so-called Industrial Benchmark (IB), a novel reinforcement learning (RL) benchmark that aims at being realistic by including a variety of aspects found in industrial applications, like continuous state and action spaces, a high dimensional, partially observable state space, delayed effects, and complex stochasticity. The experimental results of PSO-P on IB are compared to results of closed-form control policies derived from the model-based Recurrent Control Neural Network (RCNN) and the model-free Neural Fitted Q-Iteration (NFQ). Experiments show that PSO-P is not only of interest for academic benchmarks, but also for real-world industrial applications, since it also yielded the best performing policy in our IB setting. Compared to other well established RL techniques, PSO-P produced outstanding results in performance and robustness, requiring only a relatively low amount of effort in finding adequate parameters or making complex design decisions

A Benchmark Environment Motivated by Industrial Control Problems

In the research area of reinforcement learning (RL), frequently novel and promising methods are developed and introduced to the RL community. However, although many researchers are keen to apply their methods on real-world problems, implementing such methods in real industry environments often is a frustrating and tedious process. Generally, academic research groups have only limited access to real industrial data and applications. For this reason, new methods are usually developed, evaluated and compared by using artificial software benchmarks. On one hand, these benchmarks are designed to provide interpretable RL training scenarios and detailed insight into the learning process of the method on hand. On the other hand, they usually do not share much similarity with industrial real-world applications. For this reason we used our industry experience to design a benchmark which bridges the gap between freely available, documented, and motivated artificial benchmarks and properties of real industrial problems. The resulting industrial benchmark (IB) has been made publicly available to the RL community by publishing its Java and Python code, including an OpenAI Gym wrapper, on Github. In this paper we motivate and describe in detail the IB's dynamics and identify prototypic experimental settings that capture common situations in real-world industry control problems

A Benchmark Environment Motivated by Industrial Control Problems

In the research area of reinforcement learning (RL), frequently novel and promising methods are developed and introduced to the RL community. However, although many researchers are keen to apply their methods on real-world problems, implementing such methods in real industry environments often is a frustrating and tedious process. Generally, academic research groups have only limited access to real industrial data and applications. For this reason, new methods are usually developed, evaluated and compared by using artificial software benchmarks. On one hand, these benchmarks are designed to provide interpretable RL training scenarios and detailed insight into the learning process of the method on hand. On the other hand, they usually do not share much similarity with industrial real-world applications. For this reason we used our industry experience to design a benchmark which bridges the gap between freely available, documented, and motivated artificial benchmarks and properties of real industrial problems. The resulting industrial benchmark (IB) has been made publicly available to the RL community by publishing its Java and Python code, including an OpenAI Gym wrapper, on Github. In this paper we motivate and describe in detail the IB's dynamics and identify prototypic experimental settings that capture common situations in real-world industry control problems

An Efficient Algorithm for Optimizing Adaptive Quantum Metrology Processes

Quantum-enhanced metrology infers an unknown quantity with accuracy beyond the standard quantum limit (SQL). Feedback-based metrological techniques are promising for beating the SQL but devising the feedback procedures is difficult and inefficient. Here we introduce an efficient self-learning swarm-intelligence algorithm for devising feedback-based quantum metrological procedures. Our algorithm can be trained with simulated or real-world trials and accommodates experimental imperfections, losses, and decoherence

Neue Oxochloromolybdate(V) und Dimercaptotrithion-Komplexe

Die vorliegende Arbeit befaßt sich mit der Darstellung und Charakterisierung von Oxochloromolybdate(V) und Dimercaptotrithion-Komplexen. Die Oxochloromolybdate(V) wurden via Lewis-Säure-Base Reaktion in evakuierten Glasampullen unter solvothermalen Bedingungen und die Dimercaptotrithion-Komplexe nach der Methode der diffusionsgesteuerten Grenzflächenreaktion synthetisiert. Die Charakterisierung der Produkte erfolgte mit Hilfe der Elementaranalyse und der Methode der Röntgendiffraktometrie. Bei den Oxochloromolybdate(V) konnten neben der Substanzklasse der Alkalitetrachlorooxomolybdate(V) der allgemeinen Zusammensetzung M[MoOCl4](M = Li+, Na+, K+, Rb+, und Cs+) auch zwei neue Vertreter der Alkaliheptachlorodioxodimolybdate(V) der Zusammensetzung M[Mo2O2Cl7] (M = Rb+ und Cs+) synthetisiert werden. Die Verbindungen M[MoOCl4] unterscheiden sich in zwei verschiedene Koordinationsmuster der [MoOCl4]--Anionen. Der Unterschied bei den M[Mo2O2Cl7] besteht in der Stereochemie der zweikernigen [Mo2O2Cl7]- Anionen. Desweiteren konnten schwarze nadelförmige Kristalle von (TTF)[MoOCl4] erhalten und kristallographisch aufgeklärt werden. Hier konnte neben dem planaren Tetrathiofulvalenyl-Radikalkation die gewünschten polymeren [MoOCl4]--Stränge erhalten werden. Weitere Untersuchungen zur Charakterisierung wurden durch magnetische Messungen und der Messung der elektrischen Leitfähigkeit durchgeführt. Werden die Erdalkalichloride mit MoOCl3 in Thionylchlorid umgesetzt erhält man smaragdgrüne Einkristalle der Zuammensetzung [M(SOCl2)2(MoOCl4)2] (M = Mg2+, Ca2+ und Sr2+). In den Erdalkalioxochloromolybdat(V)-SOCl2-Solvaten führt die Koordination der Polyeder zu unterschiedlichen eindimensionalen Strängen in den Strukturen. In der Bariumverbindungen liegen dagegen neben Ba2+-Kationen isolierte Oxopentachloromolybdat-Anionen [MoOCl5]- vor. Neben den bereits sehr gut untersuchten Dimercaptoisotrithion-Komplexen fand der isomere Dimercaptotrithion-Ligand in der Dithiolen-Chemie bisher sehr wenig Beachtung. Hier konnte neben einem Kupfer-Bis-Chelat-Komplex ein dreikerniger Kupfer-Komplex der Zusammensetzung (P(C4H9)4)[Cu3(dmt)3] isoliert werden. In der Struktur sind die nahezu planaren, dreikernigen [Cu3(dmt)3]--Anionen über gemeinsame (S-S)-Wechselwirkungen assoziiert. Eine magnetische Messung und die Messung der elektronischen Leitfähigkeit rundeten die Charakterisierung dieses Komplexes ab.The present work deals with the representation and characterization of Oxochloromolybdate(V) and Dimercaptotrithion complexes. Oxochloromolybdate(V) were synthesized via a Lewis-acid-base reaction in evacuated glass ampoules under solvothermal conditions,while Dimercaptotrithion complexes were formed by the method of the diffusion-steered interface reactions. All substances were produced in form of their crystals and were characterised by elemental analysis and single-crystal x-ray diffraction. The reaction of molybdenum oxytrihalide MoOCl3 with alkali halides leads to compounds of the general formula M[MoOCl4] (M = Li+, Na+, K+, Rb+, and Cs+). The [MoOCl4]--anions connect in two different patterns of coordination. Two new representatives of the Alkaliheptachlorodioxodimolybdate(V) of the composition M[Mo2O2Cl7] with M = Rb+ and Cs+ were discovered. The difference of these compounds was the Stereochemistry of the dinuclear [Mo2O2Cl7]--anions. The reaction of molybdenum oxytrihalides MoOCl3 with earth-alkali chlorides leads to compounds of the chemical composition M(SOCl2]2(MoOCl4)2] (M = Mg2+, Ca2+ and Sr2+). The earthalkalioxochloromolybdat(V)-SOCl2-solvate connect in one-dimensional single strands consisting of [Mo2O2Cl8]2--anions and to different earth-alkali coordination polyhedra. MoOCl3 with BaCl2 reacts to compound of the formula Ba[MoOCl5]. The [MoOCl5]--octahedra indicates in diffrent direction. Furthermore black needle-shaped crystals of Tetrathiofulvalenyl-tetrachlorooxomolybdat(V) (TTF)[MoOCl4] could be obtained. Here, in addition to the planar tetrathiafulvalenyl radical cation the desired polymer [MoOCl4]- strands could be located. The real structure consists of square-pyramidal [MoOCl4]- ions stacked to form columns with alternating O-Mo distances of 164,2 and 239,7 pm. The packing of the columns is disordered in that the [MoOCl4]- pyramids point either in the +a or -a direction. Further studies on the characterization were performed by magnetic measurements and the measurement of the electrical conductivity. The complexes of the isomeric Dimercaptotrithion-ligand (Dmt) are not well-known. Down to the present day only five compounds are characterised. Here, a copper-chelate complex of composition (P(C4H9)4)[Cu3(dmt)3] was isolated. In the nearly planar structure of trinuclear [Cu3(dmt)3]--anions are associated with sulphur sulphur interactions. Measurements of the magnetic and electronic conductivity were used to further characterize this complex