22 research outputs found
Vice patrol cops, courts, and the struggle over urban gay life before Stonewall
No full text"Vice Patrol: Cops, Courts, and the Struggle over Urban Gay Life chronicles how local police and criminal justice systems intruded on gay individuals, criminalizing, profiling, surveilling, and prosecuting them from the 1930's through the 1960's. Anna Lvovsky details the progression of enforcement strategies through the targeting of gay-friendly bars by liquor boards, enticement of sexual overtures by plainclothes police decoys, and surveilling of public bathrooms via peepholes and two-way mirrors to catch someone "in the act." Lvovsky shows how the use of tactics indistinguishable from entrapment to criminalize homosexual men in public and private spaces produced charges brought forward and disputed by attorneys and evidence that had to stand before judges, who at times intervened against punitive policies. In Vice Patrol the author demonstrates how developments in the psychological, medical, and sociological handling of homosexuality filtered into police stations, courthouses, and the wider culture"-
Towards practical applications of quantum optics
No full textThis DPhil thesis presents two key works towards practical applications of quantum
optics. Both works are novel and achieve competitive state-of-the-art results.
Today's most widely used method of encoding quantum information in optical
qubits is the dual-rail basis, often carried out through the polarisation of a single
photon. On the other hand, many stationary carriers of quantum information |
such as atoms | couple to light via the single-rail encoding in which the qubit
is encoded in the number of photons. As such, interconversion between the two
encodings is paramount in order to achieve cohesive quantum networks. In the first
part of this thesis, we demonstrate this by generating a hybrid entangled resource
between the two encodings and using it to teleport a dual-rail qubit onto its singlerail
counterpart. Our key results yield an average fidelity of F = (92:8±2:2)% for the
teleportation and F = (89:7 ± 2:1)% for entanglement swapping, thus confirming
the applicability of this scheme towards a real-world implementation. This work
completes the set of tools necessary for the interconversion between the three primary
encodings of a qubit in the optical field: single-rail, dual-rail and continuous-variable.
A remarkable aspect of quantum theory is that certain measurement outcomes
are entirely unpredictable to all possible observers. Such quantum events can be
harnessed to generate numbers whose randomness is asserted based upon the underlying
physical processes. In the second part of this thesis, we formally introduce
and experimentally demonstrate an ultrafast optical quantum randomness generator
that uses a totally untrusted photonic source and whose idea we have patented.
While considering completely general quantum attacks, we certify randomness at a
rate of 1:1 Gbps with a rigorous security parameter of 10-20. Our security proof is
entirely composable, thereby allowing the generated randomness to be utilised for
arbitrary applications in cryptography and beyond.</p
Quantum many-body adiabaticity, topological Thouless pump and driven impurity in a one-dimensional quantum fluid
No full textThe quantum adiabatic theorem states that a driven system can be kept arbitrarily close to the instantaneous eigenstate of its Hamiltonian if the latter varies in time slowly enough. When it comes to applying the adiabatic theorem in practice, the key question to be answered is how slow slowly enough is. This question can be an intricate one, especially for many-body systems, where the limits of slow driving and large system size may not commute. Recently we have shown how the quantum adiabaticity in many-body systems is related to the generalized orthogonality catastrophe [arXiv 1611.00663, to appear in Phys. Rev. Lett.]. We have proven a rigorous inequality relating these two phenomena and applied it to establish conditions for the quantized transport in the topological Thouless pump. In the present contribution we (i) review these developments and (ii) apply the inequality to establish the conditions for adiabaticity in a one-dimensional system consisting of a quantum fluid and an impurity particle pulled through the fluid by an external force. The latter analysis is vital for the correct quantitative description of the phenomenon of quasi-Bloch oscillations in a one-dimensional translation invariant impurity-fluid system.</p
Comparison of shaping ability of ProTaper Next and 2Shape nickel–titanium files in simulated severe curved canals. Analisi sperimentale della preparazione endodontica in canali artificiali con curvature complesse: ProTaper Next Vs. 2Shape
No full textAim
To evaluate the centering ability of ProTaper Next (PTN) and 2Shape (TS) nickel–titanium (NiTi) instruments in terms of maintaining the original root canal configuration in a simulated tooth with severe curvature.
Methodology
Twenty standardized simulated curved root canals were prepared to an apical size of 0.25 mm using PTN and TS (n = 10 canal/group) nickel-titanium files. A gig was constructed to enable reproducible image acquisition using a photographic camera. Pre- and post-instrumented images were recorded and superimposed using a computer software. The ability of the instruments to remain centered in the canal was determined by calculating a centering ratio at three independent points of the simulated canal: coronal, middle and apical third of the curvature, using a computer software. Statistical analysis was performed using one-way analysis of variance (ANOVA) followed by independent sample t-test at 5% significance level.
Results
No significant difference was found between the two systems (p > 0.05). At the apical third, the mean centering ratio was significantly higher than the centering ratio of the coronal and the middle thirds in both TS and PTN (p < 0.05).
Conclusions
There were no significant differences in the centering ability of the ProTaper Next and 2Shape systems in simulated severe curved canals. Both systems exhibited some degree of transportation, especially in the apical third
Experiments Towards the Realization of a Nanofiber Guided Dipole Trap
No full textIn this thesis I present a developing project to elaborate a scientific platform towards the realization of light-matter interaction based on tapered optical nanofiber (TNF) that enables optical fields to interface with trapped neutral atoms in their vicinity. In such a configuration, the guided light exhibits a large portion of evanescent field into the vacuum thus laser cooled atoms can couple to the fiber mode. By trapping and cooling atoms around the nanofiber I investigated the interaction of the atoms with the field. My work presented in this thesis includes: Calculating the evanescent modes propagating through our fiber; Implementing fiber pulling setup using oxyhydrogen flame and analyzing nanofiber’s thermal dynamics and degradation; Constructing a Rubidium 87 MOT and characterizing its critical parameters; Realizing some atom-light interface through an experiment on coupling spontaneously emitted photons from MOT into TNF; Calculating two-color dipole trap parameters for our nanofiber
Centering Abilities of Two Rotary Niti Systems in Medium Curved Canals
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Objectives: The aim of our study was to compare the centering ability of two recently introduced NITI file
systems-New One ShapeTM and Protaper NextTM.
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Quantum physics: an introduction based on photons
No full textThis textbook is intended to accompany a two-semester course on quantum mechanics for physics students. Along with the traditional material covered in such a course (states, operators, Schrödinger equation, hydrogen atom), it offers in-depth discussion of the Hilbert space, the nature of measurement, entanglement, and decoherence – concepts that are crucial for the understanding of quantum physics and its relation to the macroscopic world, but rarely covered in entry-level textbooks. The book uses a mathematically simple physical system – photon polarization – as the visualization tool, permitting the student to see the entangled beauty of the quantum world from the very first pages. The formal concepts of quantum physics are illustrated by examples from the forefront of modern quantum research, such as quantum communication, teleportation and nonlocality. The author adopts a Socratic pedagogy: The student is guided to develop the machinery of quantum physics independently by solving sets of carefully chosen problems. Detailed solutions are provided
Promalactis merangirella Lvovksy 2000
No full textPromalactis merangirella Lvovksy, 2000a Promalactis merangirella Lvovsky, 2000a: 676. TL: Dolok Merangir, Indonesia. Diagnosis (Figures 2h, 3h, 4f, 4 fa,b) This species is superficially similar to Promalactis mooatana sp. nov. in the fore wing pattern, but it can be easily differentiated by the heavily oblique antemedial band and the larger costal patch reaching halfway across wing, and the male genitalia with cornutus absent. The first author checked the adult characters given by Wang et al. (2013) and the genitalic characters based on the figures by Lvovsky (2000a). In the taxonomical key of Southeast Asian Promalactis by Wang et al. (2013), this species has one band (= fascia) in the wing pattern, but the specimen of the species examined in this study has two bands: a subbasal band and an antemedial band. The male genitalic character of this species is well accordance with those of P. merangirella given by Lvovsky (2000a). It is necessary to check the fore wing of the species in further study. Material examined One male. Indonesia, Sumatra U., 43 km, southwest P. Siantar (HW4), 1200 m, 24–26 July 1992, J.B. Heppner, gen. slide No. 9311/S Kim. Distribution Indonesia (Sumatra: North, Northeast).Published as part of Kim, Sora, Heppner, John B. & Park, Kyu-Tek, 2017, Eight new species of the genus Promalactis (Lepidoptera: Oecophoridae) from Indonesia, with a checklist of the genus, pp. 1671-1695 in Journal of Natural History 51 (29 - 30) on page 1690, DOI: 10.1080/00222933.2017.1353154, http://zenodo.org/record/474679
Exploratory combinatorial optimization with reinforcement learning
No full textMany real-world problems can be reduced to combinatorial optimization on a graph, where the subset or ordering of vertices that maximize some objective function must be found. With such tasks often NP-hard and analytically intractable, reinforcement learning (RL) has shown promise as a framework with which efficient heuristic methods to tackle these problems can be learned. Previous works construct the solution subset incrementally, adding one element at a time, however, the irreversible nature of this approach prevents the agent from revising its earlier decisions, which may be necessary given the complexity of the optimization task. We instead propose that the agent should seek to continuously improve the solution by learning to explore at test time. Our approach of exploratory combinatorial optimization (ECO-DQN) is, in principle, applicable to any combinatorial problem that can be defined on a graph. Experimentally, we show our method to produce state-of-the-art RL performance on the Maximum Cut problem. Moreover, because ECO-DQN can start from any arbitrary configuration, it can be combined with other search methods to further improve performance, which we demonstrate using a simple random search
Towards interconversion between discrete- and continuous-variable encodings in quantum optics
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