Identifying optimal cycles in quantum thermal machines with reinforcement-learning

The optimal control of open quantum systems is a challenging task but has a key role in improving existing quantum information processing technologies. We introduce a general framework based on reinforcement learning to discover optimal thermodynamic cycles that maximize the power of out-of-equilibrium quantum heat engines and refrigerators. We apply our method, based on the soft actor-critic algorithm, to three systems: a benchmark two-level system heat engine, where we find the optimal known cycle; an experimentally realistic refrigerator based on a superconducting qubit that generates coherence, where we find a non-intuitive control sequence that outperforms previous cycles proposed in literature; a heat engine based on a quantum harmonic oscillator, where we find a cycle with an elaborate structure that outperforms the optimized Otto cycle. We then evaluate the corresponding efficiency at maximum power.

Zmiany sieci pozamiejskiego publicznego transportu autobusowego w Bieszczadach i Beskidzie Niskim – ujęcie topologiczne

W artykule autor powraca do klasycznych niegdyś w geografii transportu metod grafowych. Wykorzystując podstawowe wskaźniki, takie jak liczba cyklomatyczna μ, wskaźnik α Kansky’ego, wskaźnik γ Kansky’ego i wskaźnik Gns opracowany przez A. Ciechańskiego analizuje zmiany sieci pozamiejskiego autobusowego publicznego transportu zbiorowego na obszarze Beskidu Niskiego i Bieszczad. Testuje też wskaźnik Gns dla bardziej rozbudowanych grafów o skomplikowanej strukturze, w tym również często z bardzo licznymi izolowanymi wierzchołkami. Niestety w przeciwieństwie do prostych i niespójnych sieci transportowych, dla których został on skonstruowany, w przypadku dużych sieci transportowych, zawierających liczne cykle jego czułość wykazuje znacznie gorszy poziom, a otrzymane wyniki są znacznie mniej jednoznaczne niż w przypadku gdy izolowane podgrafy są mniej liczne, za to o bardziej rozbudowanej strukturze. Słowa kluczowe: metody grafowe, wskaźnik Gns, zmiany sieci pozamiejskiego publicznego transportu zbiorowego, Beskid Niski, Bieszczady Changes in the network of the non-urban public bus transport in Bieszczady and Beskid Niski mountains – a topological approach In the article, the author returns to the graph methods which were once classic in the transport geography. Using basic indicators such as the cyclomatic number μ, the α Kansky index, the γ Kansky index and the Gns index developed by A. Ciechański, he analyzes the changes in the network of non-urban public bus transport in the area of the Beskid Niski and the Bieszczady Mountains. He also tests the Gns indicator for more complex graphs with a complicated structure, including often very numerous isolated vertices. Unfortunately, unlike the simple and inconsistent transport networks for which it was created, in the case of large transport networks containing many cycles its sensitivity shows a much worse level and the obtained results are much less unambiguous than in the case when the isolated subgraphs are less numerous, but with the more elaborate structure.

Features Of Hippocampal Astrocytic Domains And Their Spatial Relation To Excitatory And Inhibitory Neurons

SUMMARYThe mounting evidence for the involvement of astrocytes in neuronal circuits function and behavior stands in stark contrast to the lack of detailed anatomical description of these cells and the neurons in their domains. To fill this void, we imaged >30,000 astrocytes in cleared hippocampi, and employed converging genetic, histological and computational tools to determine the elaborate structure, distribution and neuronal content of astrocytic domains. First, we characterized the spatial distribution of >19,000 astrocytes across CA1 lamina, and analyzed the detailed morphology of thousands of reconstructed domains. We then determined the excitatory content of CA1 astrocytes, averaging above 13 pyramidal neurons per domain and increasing towards CA1 midline. Finally, we discovered that somatostatin neurons are found in close proximity to astrocytes, compared to parvalbumin and VIP inhibitory neurons. This resource expands our understanding of fundamental hippocampal design principles, and provides the first quantitative foundation for neuron-astrocyte interactions in this region.

‘strange architecture’: Ciaran Carson's Until Before After

Ciaran Carson's Until Before After (2010), like many of Carson's recent books of poetry and prose, has an elaborate structure which does not obviously relate to the meaning and nature of the poetry in the volume. This essay suggests that it may be possible to ‘unlock’ meanings from the ‘strange architecture’ of Until Before After. Quentin Meillassoux's Le Nombre et La Sirène (2011) offers an example of a type of critical reading which pays attention to the intricacies (and numbers) of poetic form, in Meillassoux's case in a reading of Mallarmé’s Coup de Dés. Carson's Until Before After, in its unusual page constructions, use of partial sonnets, and potential hints at numerology, along with its allusions to Biblical and philosophical texts, can be read as being built around a pyramidal, mathematical form, which in turn is appropriate to its themes of death and resurrection.

THE LATE-VICTORIAN HISTORIES OF INDIAN ART OBJECTS: POLITICS AND AESTHETICS IN JAIPUR'S ALBERT HALL MUSEUM

Recent guidebooks for the Westerner traveling to Northern India generally refer the prospective visitor to a common range of cities around Delhi – Agra, Jaipur, and Udaipur; within these, the Taj Mahal, Jaipur's Pink City and nearby Amber Fort, and Udaipur's glamorous lake palaces usually merit must-see status. Until its refurbishment a few years ago, the Albert Hall Museum, an elaborate structure with old-fashioned interiors and a location a kilometer south of Jaipur's city center, ranked as a second- or even third-tier tourist attraction; travel guides from recent years mention it with indifference, describing its collections as “dusty” and “fine, if carelessly exhibited” (Bindloss and Singh 170), or even suggesting that “a slow circular turn around the building in a car will suffice” (Frommers 520). Yet a century ago the Museum proudly occupied a primary place in British travel guides to India. It opened with ceremony and fanfare in 1887, and by 1898 almost three million Indian and over ten thousand European visitors had passed through its doors (Hendley, Report 9). A striking example of colonial architecture, constructed of white stone with numerous courtyards, covered walkways, and ornamented domes (Figure 1), it was regarded as perhaps the most noteworthy edifice within a noteworthy Indian city. Thomas Holbein Hendley, resident Surgeon-Major in Jaipur, chief curator for the 1883 Jaipur Exhibition, and the Albert Hall Museum's Secretary and tireless champion, recommended that travelers in Jaipur for a single day make two visits, both morning and evening, to the site, and that those with an additional day to spend in the city schedule a third visit. Murray's Handbook for Travellers in India, Burma and Ceylon concurred, describing it as “a beautiful museum – an Oriental South Kensington, suitably housed” (174), and just after the turn of the century, English journalist Sidney Low recalled that it was “the best museum, with one exception, in all India, a museum which, in the careful selection and the judicious arrangement of its contents, is a model of what such an institution ought to be” (114).

Armed Forces

In early 1645 Field Marshal Lennard Torstensson led a Swedish army of 9,000 cavalry, 6,000 infantry, and sixty cannon against a Habsburg-Imperial army of 10,000 cavalry, 5,000 infantry, and twenty-six cannon commanded by Melchior von Hatzfeld. Both armies were composed of regiments commanded by international colonel-proprietors, who had used their funds or credit to raise and maintain military units. Many of the soldiers in both armies had been in service for ten years or more. The colonel-proprietors and generals in both armies regarded the recruitment of their experienced veterans as a long-term investment, and both were supported in their enterprises by an international network of private credit facilities, munitions manufacturers, food suppliers, and transport contractors. In both cases this elaborate structure was funded through control of the financial resources of entire territories, largely extracted and administered by the military high command. The armies clashed at Jankow in Bohemia, and the Imperial forces, though superior in cavalry, were held and eventually defeated by the Swedes, in part thanks to their artillery.

From the Classroom: A house for Sarah

Our class of four-year-olds spent seven weeks constructing a two-story dollhouse complete with a balcony and an attic. As students and teachers pass by our class, they are amazed to learn that the youngest children in the school made this elaborate structure.