Entrepreneurship, Institutions, and the Informal Economy

This dissertation comprises three essays which investigate the empirical relationships between institutions (formal and informal), entrepreneurial outcomes (productive and unproductive), and shadow economy size at the U.S. state-level. Chapter 1 opens with some discussion of the topics explored here and provides an overview of important results from each of the essays. In Chapter 2, the first of the empirical essays, I focus on U.S. shadow economies, providing estimates of shadow economy size for 50 U.S. states over the period 1997 to 2008 as a foundation for analysis in the subsequent chapter. Chapter 3 focuses on the relationship between entrepreneurship, shadow economy size, and corruption at the U.S. state-level. Specifically, I question the importance of the entrepreneur\u27s choice (for which estimates of shadow economy size serve as a proxy) to participate in the formal or informal economy as a channel through which public official corruption affects observed (formal sector) entrepreneurial outcomes. Chapter 4 is a joint effort with Andrew Young. In this essay we revisit Baumol\u27s (1990) conjectures on the role of institutions in determining whether entrepreneurs will channel their efforts towards wealth-generating activities or toward zero- or negative-sum rent-seeking, using cross-section data on informal, religious institutions. Chapter 5 summarizes the conclusions of the aforementioned chapters and discusses some possibilities for further investigation

The Heisenberg limit for laser coherence

To quantify quantum optical coherence requires both the particle- and wave-natures of light. For an ideal laser beam [1,2,3], it can be thought of roughly as the number of photons emitted consecutively into the beam with the same phase. This number, $\mathfrak{C}$, can be much larger than $\mu$, the number of photons in the laser itself. The limit on $\mathfrak{C}$ for an ideal laser was thought to be of order $\mu^2$ [4,5]. Here, assuming nothing about the laser operation, only that it produces a beam with certain properties close to those of an ideal laser beam, and that it does not have external sources of coherence, we derive an upper bound: $\mathfrak{C} = O(\mu^4)$. Moreover, using the matrix product states (MPSs) method [6,7,8,9], we find a model that achieves this scaling, and show that it could in principle be realised using circuit quantum electrodynamics (QED) [10]. Thus $\mathfrak{C} = O(\mu^2)$ is only a standard quantum limit (SQL); the ultimate quantum limit, or Heisenberg limit, is quadratically better.Comment: 6 pages, 4 figures, and 31 pages of supplemental information. v2: This paper is now published [Nature Physics DOI:10.1038/s41567-020-01049-3 (26 October 2020)]. For copyright reasons, this arxiv paper is based on a version of the paper prior to the accepted (21 August 2020) versio

Necessary condition for steerability of arbitrary two-qubit states with loss

Einstein-Podolsky-Rosen steering refers to the quantum phenomenon whereby the state of a system held by one party can be "steered" into different states at the will of another, distant, party by performing different local measurements. Although steering has been demonstrated in a number of experiments involving qubits, the question of which two-qubit states are steerable remains an open theoretical problem. Here, we derive a necessary condition for any two-qubit state to be steerable when the steering party suffers from a given probability of qubit loss. Our main result finds application in one-way steering demonstrations that rely upon loss. Specifically, we apply it to a recent experiment on one-way steering with projective measurements and POVMs, reported by Wollmann et. al. [Phys. Rev. Lett., 116, 160403 (2016)].Comment: 7 pages, 1 figur

Scalable multiparty steering based on a single pair of entangled qubits

The distribution and verification of quantum nonlocality across a network of users is essential for future quantum information science and technology applications. However, beyond simple point-to-point protocols, existing methods struggle with increasingly complex state preparation for a growing number of parties. Here, we show that, surprisingly, multiparty loophole-free quantum steering, where one party simultaneously steers arbitrarily many spatially separate parties, is achievable by constructing a quantum network from a set of qubits of which only one pair is entangled. Using these insights, we experimentally demonstrate this type of steering between three parties with the detection loophole closed. With its modest and fixed entanglement requirements, this work introduces a scalable approach to rigorously verify quantum nonlocality across multiple parties, thus providing a practical tool towards developing the future quantum internet

Conclusive experimental demonstration of one-way Einstein-Podolsky-Rosen steering

Einstein-Podolsky-Rosen steering is a quantum phenomenon wherein one party influences, or steers, the state of a distant party's particle beyond what could be achieved with a separable state, by making measurements on one half of an entangled state. This type of quantum nonlocality stands out through its asymmetric setting, and even allows for cases where one party can steer the other, but where the reverse is not true. A series of experiments have demonstrated one-way steering in the past, but all were based on significant limiting assumptions. These consisted either of restrictions on the type of allowed measurements, or of assumptions about the quantum state at hand, by mapping to a specific family of states and analysing the ideal target state rather than the real experimental state. Here, we present the first experimental demonstration of one-way steering free of such assumptions. We achieve this using a new sufficient condition for non-steerability, and, although not required by our analysis, using a novel source of extremely high-quality photonic Werner states.Comment: Supplemental Material included in the documen

The Role of Soy in Vegetarian Diets

Soyfoods have long been prized among vegetarians for both their high protein content and versatility. Soybeans differ markedly in macronutrient content from other legumes, being much higher in fat and protein, and lower in carbohydrate. In recent years however, soyfoods and specific soybean constituents, especially isoflavones, have been the subject of an impressive amount of research. Nearly 2,000 soy-related papers are published annually. This research has focused primarily on the benefits that soyfoods may provide independent of their nutrient content. There is particular interest in the role that soyfoods have in reducing risk of heart disease, osteoporosis and certain forms of cancer. However, the estrogen-like effects of isoflavones observed in animal studies have also raised concerns about potential harmful effects of soyfood consumption. This review addresses questions related to soy and chronic disease risk, provides recommendations for optimal intakes, and discusses potential contraindications. As reviewed, the evidence indicates that, with the exception of those individuals allergic to soy protein, soyfoods can play a beneficial role in the diets of vegetarians. Concerns about adverse effects are not supported by the clinical or epidemiologic literature. Based on the soy intake associated with health benefits in the epidemiologic studies and the benefits noted in clinical trials, optimal adult soy intake would appear to be between two and four servings per day

U.S. Shadow Economies, Corruption, and Entrepreneurship: State-level Spatial Relations

This paper offers a new theory of relationship between corruption and the shadow economy, one that defines it as either collusive – i.e., crony – or non - collusive. Using new estimates of state - level shadow economy size and data on corruption convictions of U.S. public officials for the 48 contiguous states, this study revisits this relationship empirically, controlling for spatial dependence. Additionally, the relationship between entrepreneurship and cronyism is investigated using productive entrepreneurship scores from Wiseman and Young (2014). Findings suggest that corruption and shadow economy size are positively related and both contagious and cross - contagious in the U.S. states. These results are fairly robust to several methods of spatial modeling. Results also reveal that productive entrepreneurship is contagious across states. Finally, this study attempt s to draw a linkage among formal sector entrepreneurial outcomes, corruption, and the shadow economy using spatial GMM/IV modeling in an entrepreneurship regression