Quantum-Proof Extractors: Optimal up to Constant Factors

We give the first construction of a family of quantum-proof extractors that has optimal seed length dependence O(log(n/ǫ)) on the input length n and error ǫ. Our extractors support any min-entropy k = Ω(log n + log1+α (1/ǫ)) and extract m = (1 − α)k bits that are ǫ-close to uniform, for any desired constant α > 0. Previous constructions had a quadratically worse seed length or were restricted to very large input min-entropy or very few output bits. Our result is based on a generic reduction showing that any strong classical condenser is automatically quantum-proof, with comparable parameters. The existence of such a reduction for extractors is a long-standing open question; here we give an affirmative answer for condensers. Once this reduction is established, to obtain our quantum-proof extractors one only needs to consider high entropy sources. We construct quantum-proof extractors with the desired parameters for such sources by extending a classical approach to extractor construction, based on the use of block-sources and sampling, to the quantum setting. Our extractors can be used to obtain improved protocols for device-independent randomness expansion and for privacy amplification

Quantum-Proof Extractors: Optimal up to Constant Factors

We give the first construction of a family of quantum-proof extractors that has optimal seed length dependence O(log(n/ǫ)) on the input length n and error ǫ. Our extractors support any min-entropy k = Ω(log n + log1+α (1/ǫ)) and extract m = (1 − α)k bits that are ǫ-close to uniform, for any desired constant α > 0. Previous constructions had a quadratically worse seed length or were restricted to very large input min-entropy or very few output bits. Our result is based on a generic reduction showing that any strong classical condenser is automatically quantum-proof, with comparable parameters. The existence of such a reduction for extractors is a long-standing open question; here we give an affirmative answer for condensers. Once this reduction is established, to obtain our quantum-proof extractors one only needs to consider high entropy sources. We construct quantum-proof extractors with the desired parameters for such sources by extending a classical approach to extractor construction, based on the use of block-sources and sampling, to the quantum setting. Our extractors can be used to obtain improved protocols for device-independent randomness expansion and for privacy amplification

Probing Power-Absorbing Structures at Near-Infrared Wavelengths using Energy Absorption Interferometry

Energy Absorption Interferometry was recently proposed as an interferometric technique capable of fully characterizing the optical response of single-mode, few-mode and multi- mode power-absorbing structures, such as near-infrared detectors. A detector’s output can be written as the full spatial contraction of the external field correlation tensor and detector response correlation tensor representing their respective spatial coherence states; EAI recovers the latter, solely using power measurements. EAI is essentially a generalization of holography, and allows the reconstruction of the individual degrees of freedom through which the device under test can absorb energy, including their relative sensitivities and spatial forms. The natural modes of the detector response are intimately related to its optical coupling mechanisms and the underlying solid-state phenomena responsible for power absorption: their study therefore has direct applications in improving current infrared detector technology. In particular, device properties dependent on its geometry and material are directly obtained, such as the absorber’s spatial coherence length. EAI yields an experimental procedure where the system under test is excited with two external coherent sources, and the fringe in the total power dissipated is measured as the relative phase between the sources is varied. Iterating for multiple source positions, the fringes’ complex amplitudes allow the two-point detector response function to be retrieved: this correlation function can then be decomposed into a set of natural modes. In this thesis, we demonstrate the application of EAI at near-infrared wavelengths. We describe the theoretical basis of EAI and numerically investigate its feasibility at infrared wavelengths. We present for the first time the design of a room-temperature, fiber-based, 1550 nm-wavelength experiment and its performance. We report the first measurement of the complex-valued DRF of fiber-coupled photodetectors, with single-mode, few-mode and multi-mode behaviors; this includes extending the experimental system to suppress environmental phase drift in optical fibers. We recover the natural modes of the devices under test, and compare their spatial forms to numerical simulations. Finally, we discuss the application of EAI to many-body structures as varied as spin systems and energy-harvesting absorbers, and its extension to measure quantum correlation functions using a pair of probes creating generalized forces

The Value of Technics: An Ontogenetic Approach to Money, Markets, and Networks

This thesis investigates the impact of the digitalization of monetary and financial flows on the political-economic sphere in order to provide a novel perspective on the relations between economic and technological forces at the present global juncture. In the aftermath of the Global Financial Crisis and with the rise of the cryptoeconomy, an increasing number of scholars have highlighted the immanence of market logic to cultural and social life. At the same time, speculative practices have emerged that attempt to challenge the political economy through financial experiments. This dissertation complements these approaches by stressing the need to pair the critical study of finance with scholarship in the philosophy of technology that emphasizes the value immanent to technics and technology – i.e. the normative and genetic role of ubiquitous algorithmic networks in the organization of markets and socius. In order to explore these events, I propose an interdisciplinary theoretical framework informed largely by Gilbert Simondon’s philosophy of individuation and technics and the contemporary literature on the ontology of computation, supported by insights drawn from the history of finance and economic theory. This novel framework will provide the means to investigate the ontogenetic processes at work in the techno-cultural ecosystem following the digitalization of monetary and financial flows. Through an exploration of the fleeting materiality and multifaceted character of digital fiat money, the social power of algorithmic financial logic, and the new possibilities offered by the invention of the Bitcoin protocol, this research aims to challenge some of the bedrocks of the economic orthodoxy – economic and monetary value, liquidity, market rationality – in order to move beyond the overarching narrative of capitalism as a monolithic system. The thesis instead foregrounds the techno-historical contingencies that have led to the contemporary power formation. Furthermore, it argues that the ontogenetic character of algorithmic technology ushers in novel possibilities for the speculative engineering of alternative networks of value creation and distribution that have the potential to reverse the current balance of power

Putting Chinese natural knowledge to work in an eighteenth-century Swiss canton: the case of Dr Laurent Garcin

Symposium: S048 - Putting Chinese natural knowledge to work in the long eighteenth centuryThis paper takes as a case study the experience of the eighteenth-century Swiss physician, Laurent Garcin (1683-1752), with Chinese medical and pharmacological knowledge. A Neuchâtel bourgeois of Huguenot origin, who studied in Leiden with Hermann Boerhaave, Garcin spent nine years (1720-1729) in South and Southeast Asia as a surgeon in the service of the Dutch East India Company. Upon his return to Neuchâtel in 1739 he became primus inter pares in the small local community of physician-botanists, introducing them to the artificial sexual system of classification. He practiced medicine, incorporating treatments acquired during his travels. taught botany, collected rare plants for major botanical gardens, and contributed to the Journal Helvetique on a range of topics; he was elected a Fellow of the Royal Society of London, where two of his papers were read in translation and published in the Philosophical Transactions; one of these concerned the mangosteen (Garcinia mangostana), leading Linnaeus to name the genus Garcinia after Garcin. He was likewise consulted as an expert on the East Indies, exotic flora, and medicines, and contributed to important publications on these topics. During his time with the Dutch East India Company Garcin encountered Chinese medical practitioners whose work he evaluated favourably as being on a par with that of the Brahmin physicians, whom he particularly esteemed. Yet Garcin never went to China, basing his entire experience of Chinese medical practice on what he witnessed in the Chinese diaspora in Southeast Asia (the ‘East Indies’). This case demonstrates that there were myriad routes to Europeans developing an understanding of Chinese natural knowledge; the Chinese diaspora also afforded a valuable opportunity for comparisons of its knowledge and practice with other non-European bodies of medical and natural (e.g. pharmacological) knowledge.postprin