Dealing with natural language interfaces in a geolocation context

In the geolocation field where high-level programs and low-level devices coexist, it is often difficult to find a friendly user inter- face to configure all the parameters. The challenge addressed in this paper is to propose intuitive and simple, thus natural lan- guage interfaces to interact with low-level devices. Such inter- faces contain natural language processing and fuzzy represen- tations of words that facilitate the elicitation of business-level objectives in our context

Tsirelson's bound and Landauer's principle in a single-system game

We introduce a simple single-system game inspired by the Clauser-Horne-Shimony-Holt (CHSH) game. For qubit systems subjected to unitary gates and projective measurements, we prove that any strategy in our game can be mapped to a strategy in the CHSH game, which implies that Tsirelson's bound also holds in our setting. More generally, we show that the optimal success probability depends on the reversible or irreversible character of the gates, the quantum or classical nature of the system and the system dimension. We analyse the bounds obtained in light of Landauer's principle, showing the entropic costs of the erasure associated with the game. This shows a connection between the reversibility in fundamental operations embodied by Landauer's principle and Tsirelson's bound, that arises from the restricted physics of a unitarily-evolving single-qubit system.Comment: 7 pages, 5 figures, typos correcte

Reliable experimental quantification of bipartite entanglement without reference frames

Simply and reliably detecting and quantifying entanglement outside laboratory conditions will be essential for future quantum information technologies. Here we address this issue by proposing a method for generating expressions which can perform this task between two parties who do not share a common reference frame. These reference frame independent expressions only require simple local measurements, which allows us to experimentally test them using an off-the-shelf entangled photon source. We show that the values of these expressions provide bounds on the concurrence of the state, and demonstrate experimentally that these bounds are more reliable than values obtained from state tomography since characterizing experimental errors is easier in our setting. Furthermore, we apply this idea to other quantities, such as the Renyi and von Neumann entropies, which are also more reliably calculated directly from the raw data than from a tomographically reconstructed state. This highlights the relevance of our approach for practical quantum information applications that require entanglement

Information Theoretically Secure Hypothesis Test for Temporally Unstructured Quantum Computation

We propose a new composable and information-theoretically secure protocol to verify that a server has the power to sample from a sub-universal quantum machine implementing only commuting gates. By allowing the client to manipulate single qubits, we exploit properties of Measurement based Blind Quantum Computing to prove security against a malicious Server and therefore certify quantum supremacy without the need for a universal quantum computer

Practical Quantum Coin Flipping

In this article we show for the first time that quantum coin flipping with security guarantees that are strictly better than any classical protocol is possible to implement with current technology. Our protocol takes into account all aspects of an experimental implementation like losses, multi-photon pulses emitted by practical photon sources, channel noise, detector dark counts and finite quantum efficiency. We calculate the abort probability when both players are honest, as well as the probability of one player forcing his desired outcome. For channel length up to 21 km, we achieve a cheating probability that is better than in any classical protocol. Our protocol is easy to implement using attenuated laser pulses, with no need for entangled photons or any other specific resources.Comment: v2, 4 pages, 3 figure

Σχεδιασμός Διαχείρισης Απορριμάτων. Το παράδειγμα του Τοπικού Σχεδίου Διαχείρισης Απορριμμάτων του Δήμου Ζωγράφου. Αξιολόγηση του σχεδιασμού και προτάσεις βελτίωσης, αξιοποιώντας τη διεθνή εμπειρία

Η αλόγιστη απόρριψη των αποβλήτων στους ΧΥΤΑ δημιούργησε στον πλανήτη περιβαλλοντικά και υγειονομικά προβλήματα, τα οποία πρέπει να αντιμετωπιστούν άμεσα. Βάσει της ευρωπαϊκής οδηγίας όλα τα κράτη-μέλη έχουν την υποχρέωση να εντάξουν στο νομοθετικό πλαίσιο τους τη διαχείριση των αποβλήτων και να εκπονήσουν σχέδια διαχείρισης για την αντιμετώπιση τους. Η παρούσα διπλωματική αφορά το Τοπικό Σχέδιο Διαχείρισης του Δήμου Ζωγράφου και τη σύνταξη προτάσεων για τη βελτίωσή του βάσει της διεθνούς εμπειρίας. Αρχικώς, παρατέθηκε η Ευρωπαϊκή νομοθεσία που αφορά τα απόβλητα με μια μικρή ιστορική αναδρομή από την έναρξης της Κοινοτικής Πολιτικής μέχρι το 7ο Ευρωπαϊκό Πρόγραμμα Δράσης για το Περιβάλλον. Έγινε αναφορά στην ελληνική νομοθεσία για τη διαχείριση των απορριμμάτων, η οποία εναρμονίζεται πλήρως με την ευρωπαϊκή. Έπειτα, αναπτύχθηκαν το Εθνικό (ΕΣΔΑ) και το Περιφερειακό (Αττικής-ΠΕΣΔΑ) Σχέδιο Διαχείρισης Απορριμμάτων. Στη συνέχεια μελετήθηκε εκτενώς το Τοπικό Σχέδιο Αποκεντρωμένης Διαχείρισης Απορριμμάτων (ΤΣΔΑ) του Δήμου Ζωγράφου. Έγινε ανάλυση της υφιστάμενης κατάστασης με αναφορές σε στατιστικά δεδομένα για την παραγωγή και τη διαχείριση των ΑΣΑ καθώς και η αξιολόγησή της. Απώτερος σκοπός του Σχεδίου ήταν η πρόταση βελτιωμένων δράσεων διαχείρισης για κάθε ρεύμα των ΑΣΑ του Δήμου Ζωγράφου. Αναφέρθηκαν οι πηγές χρηματοδότησης και το χρονοδιάγραμμα των δράσεων για το 2016. Εξετάστηκαν πρακτικές και στρατηγικές διαχείρισης απορριμμάτων στον πλανήτη, οι οποίες έχουν θετικά αποτελέσματα στη μείωση παραγωγής αποβλήτων. Παρατέθηκαν οικονομικά και στατιστικά στοιχεία των παραπάνω σχεδίων. Σκοπός της παρούσας μελέτης είναι η ανάδειξη των θετικών στοιχείων του Σχεδίου του Δήμου Ζωγράφου και η σύνταξη ολοκληρωμένων πρακτικών και δράσεων για τη βελτίωσή του, οι οποίες βασίζονται στα παραδείγματα της διεθνούς εμπειρίας που παρατέθηκαν και στις αρχές της πρόληψης, της επαναχρησιμοποίησης, της ανακύκλωσης και στην αρχή «ο ρυπαίνων πληρώνει» για την εκπλήρωση του τελικού στόχου που είναι ένας Δήμος Μηδενικών Αποβλήτων μέσω της κυκλικής οικονομίας.The improvident disposal of waste at landfills has caused the planet environmental and health problems, which have to be dealed with immediately. Under European Directive all Member States have an obligation to include in their legislative framework the waste management and to develop management plans for their treatment. This diploma concerns of the Local Municipality Management Plan Zografou and the drafting proposals for improvements counting on the international experience. Initially,it has been abstracted the European legislation of the waste with a brief history of the beggining of the Community policy until the 7th European Action Programme for the Environment. It has been made reference to the greek legislation for waste management, which is fully in harmony with the European. Then it has been developed the National and the Regional (Attica) Waste Management Plan. Then, it has been extensively studied the Local Decentralised Waste Management Plan of Municipality of Zografou.It haw been made an analysis of the current situation with reference to the statistical data on the production and management of MSW and its evaluation. The ultimate aim of the Plan was the proposal of improved management actions for each stream of MSW Municipality Zografou.It has been reported the sources of funding and the schedule of activities for 2016 . It has been examined the practices and the waste management strategies on the planet, which have positive effects on waste reduction. Financial and statistical data of the above projects have been reported. The purpose of this study is to highlight the positive aspects of the Plan of the Municipality of Zografou and drafting comprehensive practices and actions for improvement, based on examples of international experience based on the principles of the early prevention, reuse, recycling and 'polluter pays' for the fulfillment of the final goal of a Zero Waste Municipality through the circular economy

Benchmarking, verifying and utilising near term quantum technology

Quantum computers can, in theory, impressively reduce the time required to solve many pertinent problems. Such problems are found in applications as diverse as cryptography, machine learning and chemistry, to name a few. However, in practice the set of problems which can be solved depends on the amount and quality of the quantum resources available. With the addition of more qubits, improvements in noise levels, the development of quantum networks, and so on, comes more computing power. Motivated by the desire to measure the power of these devices as their capabilities change, this thesis explores the verification, characterisation and benchmarking techniques that are appropriate at each stage of development. We study the techniques that become available with each advance, and the ways that such techniques can be used to guide further development of quantum devices and their control software. Our focus is on advancements towards the first example of practical certifiable quantum computational supremacy; when a quantum computer demonstrably outperforms all classical computers at a task of practical concern. Doing so allows us to look a little beyond recent demonstrations of quantum computational supremacy for its own sake. Systems consisting of only a few noisy qubits can be simulated by a classical computer. While this reduces the applicability of quantum technology of this size, we first provide a methodology for using classical simulations to guide progress towards demonstrations of quantum computational supremacy. Using measurements of the noise levels present in the NQIT Q20:20 device, an ion-trap based quantum computer, we use classical simulations to predict and prepare for the performance of larger devices with similar characteristics. We identify the noise sources that are the most impactful, and simulate the effectiveness of approaches to mitigating them. As quantum technology advances, classically simulating it becomes increasingly resource intensive. However, simulations remain useful as a point of comparison against which to benchmark the performance of quantum devices. For so called ‘random quantum circuits’, such benchmarking techniques have been developed to support claims of demonstrations of quantum computational supremacy. To give better indications of the device’s performance in practice, instances of computations derived for practical applications have been used to benchmark devices. Our second contribution is to introduce a suite of circuits derived from structures that are common to many instances of computations derived for practical applications, contrasting with the aforementioned approach of using a collection of particular instances. This allows us to make broadly applicable predictions of performance, which are indicative of the device’s behaviour when investigating applications of concern. We use this suite to benchmark all layers of the quantum computing stack, exploring the interplay between the compilation strategy, device, and the computation itself. The circuit structures in the suite are sufficiently diverse to provide insights into the noise channels present in several real devices, and into the applications for which each quantum computing stack is best suited. We consider several figures of merit by which to assess performance when implementing these circuits, taking care to minimise the required number of uses of the quantum device. As our third contribution, we consider benchmarking devices performing Instantaneous Quantum Polynomial time (IQP) computations; a subset of all the computations quantum computers are capable of performing in polynomial time. By using only a commuting gate set, IQP circuits do not require the development of a universal quantum computer, but are still thought impossible to simulate efficiently on a classical computer. Utilising a small quantum network, which allows for the transmission of single qubits, we introduce an approach to benchmarking the performance of devices capable of implementing IQP computations. As the resource consumption of our benchmarking technique grows reasonably as the size of the device grows, it enables us to benchmark IQP capable devices when they are of sufficient size to demonstrate quantum computational supremacy, and indeed to certify demonstrations of quantum computational supremacy. The approach we introduce is constructed by concealing some secret structure within an IQP computation. This structure can be taken advantage of by a quantum computer, but not by a classical one, in order to prove it is capable of accurately implementing IQP circuits. To achieve this we derive an implementation of IQP circuits which keeps the computation, and as a result the structure introduced, hidden from the device being tested. We prove this implementation to be information-theoretically and composably secure. In the work described above we explore verification, characterisation and benchmarking of quantum technology both as it advances to demonstrations of quantum computational supremacy, and when it is applied to real world problems. Finally, we consider demonstrations of quantum computational supremacy with an instance of these real world problems. We consider quantum machine learning, and generative modelling in particular. Generative modelling is the task of producing new samples from a distribution, given a collection of samples from that distribution. We introduce and define ‘quantum learning supremacy’, which captures our intuitive notion of a demonstration of quantum computational supremacy in this setting, and allows us to speak formally about generative modelling tasks that can be completed by quantum, but not classical, computers. We introduce the Quantum Circuit Ising Born Machine (QCIBM), which consists of a parametrised quantum circuit and a classical optimisation loop to train the parameters, as a route to demonstrating quantum learning supremacy. We adapt results that exist for IQP circuits in order to argue that the QCIBM might indeed be used to demonstrate quantum learning supremacy. We discuss training procedures for the QCIBM, and Quantum Circuit Born Machines generally, and their implications on demonstrations of quantum learning supremacy

Multipartite entanglement verification resistant against dishonest parties

Future quantum information networks will likely consist of quantum and classical agents, who have the ability to communicate in a variety of ways with trusted and untrusted parties and securely delegate computational tasks to untrusted large-scale quantum computing servers. Multipartite quantum entanglement is a fundamental resource for such a network and hence it is imperative to study the possibility of verifying a multipartite entanglement source in a way that is efficient and provides strong guarantees even in the presence of multiple dishonest parties. In this work, we show how an agent of a quantum network can perform a distributed verification of a multipartite entangled source with minimal resources, which is, nevertheless, resistant against any number of dishonest parties. Moreover, we provide a tight tradeoff between the level of security and the distance between the state produced by the source and the ideal maximally entangled state. Last, by adding the resource of a trusted common random source, we can further provide security guarantees for all honest parties in the quantum network simultaneously.Comment: The statement of Theorem 2 has been revised and a new proof is given. Other results unchange