Necessary and sufficient conditions for macroscopic realism from quantum mechanics

Macroscopic realism, the classical world view that macroscopic objects exist independently of and are not influenced by measurements, is usually tested using Leggett-Garg inequalities. Recently, another necessary condition called no-signaling in time (NSIT) has been proposed as a witness for non-classical behavior. In this paper, we show that a combination of NSIT conditions is not only necessary but also sufficient for a macrorealistic description of a physical system. Any violation of macroscopic realism must therefore be witnessed by a suitable NSIT condition. Subsequently, we derive an operational formulation for NSIT in terms of positive operator-valued measurements and the system Hamiltonian. We argue that this leads to a suitable definition of "classical" measurements and Hamiltonians, and apply our formalism to some generic coarse-grained quantum measurements.Comment: 10 pages, published versio

Quantum violation of classical physics in macroscopic systems

While quantum theory has been tested to an incredible degree on microscopic scales, quantum effects are seldom observed in our everyday macroscopic world. The curious results of applying quantum mechanics to macroscopic objects are perhaps best illustrated by Erwin Schrödinger's famous thought experiment, where a cat can be put into a superposition state of being both dead and alive. Obviously, these quantum predictions are in stark contradiction to our common experience. Even with plenty of theoretical explanations put forward to explain this discrepancy, a large number of questions about the frontier between the quantum and the classical world remain unanswered. To distinguish between classical and quantum behavior, two fundamental concepts inherent to classical physics have been established over the years: The world view of local realism limits the power of classical experiments to establish correlations over space, while the world view of macroscopic realism (or macrorealism) restricts temporal correlations. Necessary conditions for both world views have been formulated in the form of Bell and Leggett-Garg inequalities, and Bell inequalities have been shown to be violated by quantum mechanics through increasingly conclusive experiments. Furthermore, many challenging steps towards convincing violations of macrorealism have been taken in a number of recent experiments. In the first part of this thesis, conditions for macrorealism are analyzed in detail. Two necessary conditions for macrorealism, the original Leggett-Garg inequality and the recently proposed no-signaling in time condition, are presented. It is then shown that a combination of no-signaling in time conditions is not only necessary but also sufficient for the existence of a macrorealistic description. Finally, an operational formulation of no-signaling in time, in terms of positive-operator valued measurements and Hamiltonians, is derived. In the next part, we argue that these results lead to a suitable definition of classical behavior. In particular, we provide a formalism to judge the classicality of measurements and time evolutions. We then proceed to apply it to a number of exemplary measurement operators and Hamiltonians. Finally, we argue for the importance of spontaneously realized Hamiltonians in our intuition of classical behavior. Next, differences between local realism and macrorealism are analyzed. For this purpose, the probability polytopes for spatially and temporally separated experiments are compared, and a fundamental difference in the power of quantum mechanics to build both types of correlations is discovered. This result shows that Fine's theorem, which states that a set of Bell inequalities is necessary and sufficient for local realism, is not transferable to macrorealism. Thus, (Leggett-Garg) inequalities are in principle not well-suited for tests of macrorealism, as they can never form a necessary and sufficient condition, and unnecessarily restrict the violating parameter space. No-signaling in time is both better suited and more strongly motivated from the underlying physical theory. In the final part of this thesis, a concrete experimental setup for implementing quantum experiments with macroscopic objects is proposed. It consists of a superconducting micro-sphere in the Meißner state, which is levitated by magnetic fields. Through its expelled magnetic field, the sphere's center-of-mass motion couples to a superconducting quantum circuit. Properly tuned, ground state cooling can be realized, since the sphere's motion is extremely well isolated from the surrounding environment. This setup therefore is a promising candidate for the observation of quantum effects in macroscopic systems.Obwohl Quantenmechanik auf mikroskopischen Skalen Vorhersagen trifft, die mit unglaublicher Präzision experimentell bestätigt sind, beobachten wir in unserer alltäglichen makroskopischen Welt kaum ihren Einfluss. Die Anwendung von Quantentheorie auf makroskopische Objekte liefert vielmehr außerordentlich seltsame Ergebnisse. Das bekannte Beispiel, Erwin Schrödinger's Gedankenexperiment, in dem eine Katze in einen Überlagerungszustand aus tot und lebendig gebracht werden kann, illustriert dies anschaulich. Offensichtlicherweise entspricht das nicht unseren alltäglichen Erfahrungen. Obwohl unzählige Theorien versuchen, diesen Unterschied zwischen Quantenmechanik und klassischer Physik zu erklären, bleiben viele Fragen über die Grenze zwischen diesen beiden Welten offen. Im Laufe des letzten Jahrhunderts wurden zwei fundamentale Charakteristika von klassischer Physik identifiziert, die eine Unterscheidung von klassischem und quantenmechanischem Verhalten ermöglichen: Die Weltbilder lokaler Realismus und makroskopischer Realismus (oder Makrorealismus) setzen dem Aufbau von räumlichen bzw. zeitlichen Korrelationen in klassischen Theorien prinzipielle Grenzen. Notwendige Bedingungen für beide Weltbilder wurden in Form von Bell-Ungleichungen und Leggett-Garg-Ungleichungen formuliert. Die Verletzung von Bell-Ungleichungen (und damit von lokalem Realismus) durch Quantenmechanik ist durch Experimente mit zunehmender Zuverlässigkeit bestätigt, und wichtige Schritte hin zu experimentellen Tests von Makrorealismus wurden in den letzten Jahren unternommen. Im ersten Teil dieser Dissertation werden Bedingungen für Makrorealismus im Detail analysiert. Zwei notwendige Bedingungen, die ursprüngliche Leggett-Garg-Ungleichung und die kürzlich vorgeschlagene Bedingung namens no-signaling in time werden vorgestellt. Es wird ferner gezeigt, dass eine Kombination aus no-signaling in time und Kausalitätsbedingungen sowohl hinreichend als auch notwendig für die Existenz einer makrorealistischen Beschreibung eines Experiments ist. Zuletzt wird eine operationelle Formulierung von no-signaling in time als Forderungen an POVM-Messoperatoren und den Hamiltonoperator hergeleitet. Der nächste Teil legt dar, dass sich aus den obigen Ergebnissen eine passende Definition von klassischem Verhalten ergibt. Wir definieren die Klassizität von Messungen und Zeitentwicklungen, und wenden unsere Ergebnisse auf einige beispielhafte Messoperatoren und Hamiltonoperatoren an. Ferner wird die Wichtigkeit der in der Natur spontan realisierten Wechselwirkungen für jede Definition von klassischem Verhalten diskutiert. Im dritten Teil werden Unterschiede zwischen lokalem Realismus und makroskopischem Realismus analysiert. Wir betrachten hierfür die Form der Räume, die durch die Wahrscheinlichkeitsverteilungen in beiden Fällen aufgespannt werden. Wir finden fundamentale Unterschiede in der Struktur beider Polytope, insbesondere in Bezug auf Quantenmechanik. Unsere Ergebnisse belegen, dass Fines Theorem, welches besagt, dass Bell-Ungleichungen hinreichend und notwendig für lokalen Realismus sind, nicht auf Makrorealismus übertragbar ist. Daraus folgern wir, dass (Leggett-Garg-)Ungleichungen prinizpiell nicht optimal für experimentelle Tests von Makrorealismus sind, da sie niemals hinreichend sein können, und den verletzenden Parameterraum unnötig einschränken. No-signaling in time ist somit sowohl mächtiger, als auch besser durch die zugrundeliegende Theorie motiviert. Im letzten Teil dieser Dissertation schlagen wir einen konkreten experimentellen Aufbau für Quantenexperimente mit makroskopischen Objekten vor. Er besteht aus einer supraleitenden Kugel im Mikrometerbereich im Meißner-Zustand. Die Kugel wird durch ein starkes Magnetfeld in der Schwebe gehalten und gefangen. Über das verdrängte Magnetfeld koppelt die Schwerpunktsposition der Kugel an einen supraleitenden Quantenstromkreis. Mit einem passenden Antriebsfeld kann die Schwerpunktsbewegung dann in den Quantengrundzustand gekühlt werden, da die Kugel extrem gut von der Umgebug isoliert ist. Unser Vorschlag ist damit ein vielversprechender Kandidat für die Beobachtung von Quanteneffekten in makroskopischen Systemen

Quantum violation of classical physics in macroscopic systems

While quantum theory has been tested to an incredible degree on microscopic scales, quantum effects are seldom observed in our everyday macroscopic world. The curious results of applying quantum mechanics to macroscopic objects are perhaps best illustrated by Erwin Schrödinger's famous thought experiment, where a cat can be put into a superposition state of being both dead and alive. Obviously, these quantum predictions are in stark contradiction to our common experience. Even with plenty of theoretical explanations put forward to explain this discrepancy, a large number of questions about the frontier between the quantum and the classical world remain unanswered. To distinguish between classical and quantum behavior, two fundamental concepts inherent to classical physics have been established over the years: The world view of local realism limits the power of classical experiments to establish correlations over space, while the world view of macroscopic realism (or macrorealism) restricts temporal correlations. Necessary conditions for both world views have been formulated in the form of Bell and Leggett-Garg inequalities, and Bell inequalities have been shown to be violated by quantum mechanics through increasingly conclusive experiments. Furthermore, many challenging steps towards convincing violations of macrorealism have been taken in a number of recent experiments. In the first part of this thesis, conditions for macrorealism are analyzed in detail. Two necessary conditions for macrorealism, the original Leggett-Garg inequality and the recently proposed no-signaling in time condition, are presented. It is then shown that a combination of no-signaling in time conditions is not only necessary but also sufficient for the existence of a macrorealistic description. Finally, an operational formulation of no-signaling in time, in terms of positive-operator valued measurements and Hamiltonians, is derived. In the next part, we argue that these results lead to a suitable definition of classical behavior. In particular, we provide a formalism to judge the classicality of measurements and time evolutions. We then proceed to apply it to a number of exemplary measurement operators and Hamiltonians. Finally, we argue for the importance of spontaneously realized Hamiltonians in our intuition of classical behavior. Next, differences between local realism and macrorealism are analyzed. For this purpose, the probability polytopes for spatially and temporally separated experiments are compared, and a fundamental difference in the power of quantum mechanics to build both types of correlations is discovered. This result shows that Fine's theorem, which states that a set of Bell inequalities is necessary and sufficient for local realism, is not transferable to macrorealism. Thus, (Leggett-Garg) inequalities are in principle not well-suited for tests of macrorealism, as they can never form a necessary and sufficient condition, and unnecessarily restrict the violating parameter space. No-signaling in time is both better suited and more strongly motivated from the underlying physical theory. In the final part of this thesis, a concrete experimental setup for implementing quantum experiments with macroscopic objects is proposed. It consists of a superconducting micro-sphere in the Meißner state, which is levitated by magnetic fields. Through its expelled magnetic field, the sphere's center-of-mass motion couples to a superconducting quantum circuit. Properly tuned, ground state cooling can be realized, since the sphere's motion is extremely well isolated from the surrounding environment. This setup therefore is a promising candidate for the observation of quantum effects in macroscopic systems.Obwohl Quantenmechanik auf mikroskopischen Skalen Vorhersagen trifft, die mit unglaublicher Präzision experimentell bestätigt sind, beobachten wir in unserer alltäglichen makroskopischen Welt kaum ihren Einfluss. Die Anwendung von Quantentheorie auf makroskopische Objekte liefert vielmehr außerordentlich seltsame Ergebnisse. Das bekannte Beispiel, Erwin Schrödinger's Gedankenexperiment, in dem eine Katze in einen Überlagerungszustand aus tot und lebendig gebracht werden kann, illustriert dies anschaulich. Offensichtlicherweise entspricht das nicht unseren alltäglichen Erfahrungen. Obwohl unzählige Theorien versuchen, diesen Unterschied zwischen Quantenmechanik und klassischer Physik zu erklären, bleiben viele Fragen über die Grenze zwischen diesen beiden Welten offen. Im Laufe des letzten Jahrhunderts wurden zwei fundamentale Charakteristika von klassischer Physik identifiziert, die eine Unterscheidung von klassischem und quantenmechanischem Verhalten ermöglichen: Die Weltbilder lokaler Realismus und makroskopischer Realismus (oder Makrorealismus) setzen dem Aufbau von räumlichen bzw. zeitlichen Korrelationen in klassischen Theorien prinzipielle Grenzen. Notwendige Bedingungen für beide Weltbilder wurden in Form von Bell-Ungleichungen und Leggett-Garg-Ungleichungen formuliert. Die Verletzung von Bell-Ungleichungen (und damit von lokalem Realismus) durch Quantenmechanik ist durch Experimente mit zunehmender Zuverlässigkeit bestätigt, und wichtige Schritte hin zu experimentellen Tests von Makrorealismus wurden in den letzten Jahren unternommen. Im ersten Teil dieser Dissertation werden Bedingungen für Makrorealismus im Detail analysiert. Zwei notwendige Bedingungen, die ursprüngliche Leggett-Garg-Ungleichung und die kürzlich vorgeschlagene Bedingung namens no-signaling in time werden vorgestellt. Es wird ferner gezeigt, dass eine Kombination aus no-signaling in time und Kausalitätsbedingungen sowohl hinreichend als auch notwendig für die Existenz einer makrorealistischen Beschreibung eines Experiments ist. Zuletzt wird eine operationelle Formulierung von no-signaling in time als Forderungen an POVM-Messoperatoren und den Hamiltonoperator hergeleitet. Der nächste Teil legt dar, dass sich aus den obigen Ergebnissen eine passende Definition von klassischem Verhalten ergibt. Wir definieren die Klassizität von Messungen und Zeitentwicklungen, und wenden unsere Ergebnisse auf einige beispielhafte Messoperatoren und Hamiltonoperatoren an. Ferner wird die Wichtigkeit der in der Natur spontan realisierten Wechselwirkungen für jede Definition von klassischem Verhalten diskutiert. Im dritten Teil werden Unterschiede zwischen lokalem Realismus und makroskopischem Realismus analysiert. Wir betrachten hierfür die Form der Räume, die durch die Wahrscheinlichkeitsverteilungen in beiden Fällen aufgespannt werden. Wir finden fundamentale Unterschiede in der Struktur beider Polytope, insbesondere in Bezug auf Quantenmechanik. Unsere Ergebnisse belegen, dass Fines Theorem, welches besagt, dass Bell-Ungleichungen hinreichend und notwendig für lokalen Realismus sind, nicht auf Makrorealismus übertragbar ist. Daraus folgern wir, dass (Leggett-Garg-)Ungleichungen prinizpiell nicht optimal für experimentelle Tests von Makrorealismus sind, da sie niemals hinreichend sein können, und den verletzenden Parameterraum unnötig einschränken. No-signaling in time ist somit sowohl mächtiger, als auch besser durch die zugrundeliegende Theorie motiviert. Im letzten Teil dieser Dissertation schlagen wir einen konkreten experimentellen Aufbau für Quantenexperimente mit makroskopischen Objekten vor. Er besteht aus einer supraleitenden Kugel im Mikrometerbereich im Meißner-Zustand. Die Kugel wird durch ein starkes Magnetfeld in der Schwebe gehalten und gefangen. Über das verdrängte Magnetfeld koppelt die Schwerpunktsposition der Kugel an einen supraleitenden Quantenstromkreis. Mit einem passenden Antriebsfeld kann die Schwerpunktsbewegung dann in den Quantengrundzustand gekühlt werden, da die Kugel extrem gut von der Umgebug isoliert ist. Unser Vorschlag ist damit ein vielversprechender Kandidat für die Beobachtung von Quanteneffekten in makroskopischen Systemen

Quantum memories based on engineered dissipation

Storing quantum information for long times without disruptions is a major requirement for most quantum information technologies. A very appealing approach is to use self-correcting Hamiltonians, i.e. tailoring local interactions among the qubits such that when the system is weakly coupled to a cold bath the thermalization process takes a long time. Here we propose an alternative but more powerful approach in which the coupling to a bath is engineered, so that dissipation protects the encoded qubit against more general kinds of errors. We show that the method can be implemented locally in four dimensional lattice geometries by means of a toric code, and propose a simple 2D set-up for proof of principle experiments.Comment: 6 +8 pages, 4 figures, Includes minor corrections updated references and aknowledgement

Implementação de um sistema de Business Intelligence para o suporte à tomada de decisão de um setor de produção

TCC(graduação) - Universidade Federal de Santa Catarina. Centro Tecnológico. Engenharia de Controle e Automação.O avanço tecnológico crescente relacionado a hardware e software, permite que as organizações empresariais realizem a captação automatizada, armazenamento e transformação dos dados produzidos por seus processos, e posteriormente, a transformação destes dados em informação. Este processo valoriza os dados ao contextualizar e gerar conhecimento por meio de análises e tomadas de decisão mais assertivas. A fim de se manterem competitivas frente a estas mudanças, as empresas apresentam a necessidade de desenvolver sistemas que forneçam informações baseadas em dados de maneira eficiente. Neste cenário, este documento apresenta a fundamentação teórica acerca de tecnologias de sistemas de apoio à tomada de decisão, assim como as metodologias de desenvolvimento e ferramentas que envolvem a implementação de uma solução de Business Intelligence, que tem por objetivo apresentar indicadores táticos e operacionais que dão suporte aos processos de planejamento, programação e controle de um setor de produção. O sistema desenvolvido fornece informações inferidas por dados coletados dos processos produtivos realizados pelo setor de produção de forma eficiente, permitindo o monitoramento das atividades e a rápida tomada de decisão dos gestores da área

Historia crítica de la Epístola de Horacio a los Pisones

54 p

Elaboração de um jogo multijogador assimétrico: design, desenvolvimento e publicação

Este trabalho aborda o design, o desenvolvimento e a publicação de um jogo multiplayer assimétrico. O design utilizou os frameworks MDA (Mechanics, Dynamics and Aesthetics) e 6-11 (seis emoções e onze instintos) como possibilidades para análises das ações permitidas aos jogadores e da estética do jogo. O desenvolvimento do jogo foi realizado com a engine de jogos Unity e foi utilizado o serviço Photon para prototipagem do serviço multijogador. Em seguida, a biblioteca Telepathy foi utilizada para comunicar as aplicações por meio de mensagens. Por fim, relata-se a publicação do jogo, resultados obtidos e possíveis pontos de melhorias

The effect of experience on the psychophysiological response and shooting performance under acute physical stress of soldiers

Present research studied the psychophysiological response and shooting performance taking into consideration the experience of the soldier after a physical stress protocol, which leaded to acute fatigue conditions. Sixty soldiers were divided into experienced and non-experienced groups to conduct a high-intensity interval training (HIIT) based on endurance type exercises (10 intervals of 40 m run at maximum intensity with 2 changes of direction and 45 s of recovery. Psychophysiological and shooting performance variables were measured before, during and after the HIIT protocol. Significant increases in heart rate, blood lactate, lower limbs strength, as well as a significant decrease in blood oxygen saturation and body temperature were found in both groups. Shooting performance was affected by experience and fatigue, being more accentuated in non-experienced. Present HIIT protocol elicited a similar psychophysiological response than in previously reported combat manoeuvres, thus proving to be an optimal stimuli approach/intervention for soldier's specific physical preparation

Sustainable synthesis of uridine-5′-monophosphate analogues by immobilized uracil phosphoribosyltransferase from Thermus thermophilus

Nowadays enzymatic synthesis of nucleic acid derivatives is gaining momentum over traditional chemical synthetic processes. Biotransformations catalyzed by whole cells or enzymes offer an ecofriendly and efficient alternative to the traditional multistep chemical methods, avoiding the use of chemical reagents and organic solvents that are expensive and environmentally harmful. Herein we report for the first time the covalent immobilization a uracil phosphoribosyltransferase (UPRT). In this sense, UPRT from Thermus thermophilus HB8 was immobilized onto glutaraldehyde-activated MagReSyn®Amine magnetic iron oxide porous microparticles (MTtUPRT). According to the catalyst load experiments, MTtUPRT3 was selected as optimal biocatalyst for further studies. MTtUPRT3 was active and stable in a broad range of temperature (70–100 °C) and in the pH interval 6–8, displaying maximum activity at 100 °C and pH 7 (activity 968 IU/gsupport, retained activity 100%). In addition, MTtUPRT3 could be reused up to 8 times in the synthesis of uridine-5′-monophosphate (UMP). Finally, MTtUPRT3 was successfully applied in the sustainable synthesis of different 5-modified uridine-5′-monophosphates at short times. Taking into account these results, MTtUPRT3 would emerge as a valuable biocatalyst for the synthesis of nucleoside monophosphates through an efficient and environmentally friendly methodology