A Transactional Analysis of Interaction Free Measurements

The transactional interpretation of quantum mechanics is applied to the "interaction-free" measurement scenario of Elitzur and Vaidman and to the Quantum Zeno Effect version of the measurement scenario by Kwiat, et al. It is shown that the non-classical information provided by the measurement scheme is supplied by the probing of the intervening object by incomplete offer and confirmation waves that do not form complete transactions or lead to real interactions.Comment: Accepted for publication in Foundations of Physics Letter

A quantum central limit theorem for non-equilibrium systems: Exact local relaxation of correlated states

We prove that quantum many-body systems on a one-dimensional lattice locally relax to Gaussian states under non-equilibrium dynamics generated by a bosonic quadratic Hamiltonian. This is true for a large class of initial states - pure or mixed - which have to satisfy merely weak conditions concerning the decay of correlations. The considered setting is a proven instance of a situation where dynamically evolving closed quantum systems locally appear as if they had truly relaxed, to maximum entropy states for fixed second moments. This furthers the understanding of relaxation in suddenly quenched quantum many-body systems. The proof features a non-commutative central limit theorem for non-i.i.d. random variables, showing convergence to Gaussian characteristic functions, giving rise to trace-norm closeness. We briefly relate our findings to ideas of typicality and concentration of measure.Comment: 27 pages, final versio

Entanglement area law from specific heat capacity

We study the scaling of entanglement in low-energy states of quantum many-body models on lattices of arbitrary dimensions. We allow for unbounded Hamiltonians such that systems with bosonic degrees of freedom are included. We show that if at low enough temperatures the specific heat capacity of the model decays exponentially with inverse temperature, the entanglement in every low-energy state satisfies an area law (with a logarithmic correction). This behaviour of the heat capacity is typically observed in gapped systems. Assuming merely that the low-temperature specific heat decays polynomially with temperature, we find a subvolume scaling of entanglement. Our results give experimentally verifiable conditions for area laws, show that they are a generic property of low-energy states of matter, and, to the best of our knowledge, constitute the first proof of an area law for unbounded Hamiltonians beyond those that are integrable.Comment: v3 now featuring bosonic system

Equivalence of Statistical Mechanical Ensembles for Non-Critical Quantum Systems

We consider the problem of whether the canonical and microcanonical ensembles are locally equivalent for short-ranged quantum Hamiltonians of $N$ spins arranged on a $d$-dimensional lattices. For any temperature for which the system has a finite correlation length, we prove that the canonical and microcanonical state are approximately equal on regions containing up to $O(N^{1/(d+1)})$ spins. The proof rests on a variant of the Berry--Esseen theorem for quantum lattice systems and ideas from quantum information theory

An Economic Assessment of the Myanmar Rice Sector: Current Developments and Prospects

In this study, the Myanmar rice economy is described in the context of the current political situation and state of national economic development. The forces that are changing rice production and exports are identified; however, the rate of development involves a complex integration of government intervention and politics, as well as availability of resources. Probable scenarios for rice production and export are projected based on recent growth trends and expected infrastructure development. The Arkansas Global Rice Model is used to integrate the Myanmar rice sector with the global rice market in developing projections

Thermalization and Return to Equilibrium on Finite Quantum Lattice Systems

Thermal states are the bedrock of statistical physics. Nevertheless, when and how they actually arise in closed quantum systems is not fully understood. We consider this question for systems with local Hamiltonians on finite quantum lattices. In a first step, we show that states with exponentially decaying correlations equilibrate after a quantum quench. Then we show that the equilibrium state is locally equivalent to a thermal state, provided that the free energy of the equilibrium state is sufficiently small and the thermal state has exponentially decaying correlations. As an application, we look at a related important question: When are thermal states stable against noise? In other words, if we locally disturb a closed quantum system in a thermal state, will it return to thermal equilibrium? We rigorously show that this occurs when the correlations in the thermal state are exponentially decaying. All our results come with finite-size bounds, which are crucial for the growing field of quantum thermodynamics and other physical applications.Comment: 8 pages (5 for main text and 3 for appendices); v2 is essentially the published versio

Reference effects in consumer food choice

In general, people prefer their current situation, even if they would be better off in another situation. This concept is relevant to public policy aimed at changing food habits into healthier food intake in the population. The increasing prevalence of citizens in industrialized countries being overweight or obese in the last 25 years has direct consequences on development of cardiovascular diseases, diabetes and some cancers (WHO, 2000). This is often caused by an unbalanced energy management which can be attributed to changed patterns of food consumption and a more sedentary lifestyle. Because of their repetitive nature, unhealthy food choices can be characterized as habits. A conscious decision process is therefore less likely to occur and past behaviour is often a strong predictor of current choices (Albarracin & Wyer Jr., 2000; Betsch, Haberstroh, Molter, & Glöckner, 2004; Brug, De Vet, De Nooijer, & Verplanken, 2006). The popularity of unhealthy food products is commonly ascribed to the hedonic aspects of these goods. The intrinsic appeal of hedonic goods might cause difficulties in attempts to change preferences for unhealthy food. This thesis focuses on reference effects to relate unconscious processes to consumer decision making for food products. In an intuitive type of reasoning, a person might be more vulnerable to the use of heuristics and biases in a choice situation (Kahneman, 2003). One of these biases is loss aversion which is explained by Prospect Theory (Kahneman & Tversky, 1979). According to Prospect Theory, the loss of utility associated with giving up a good is perceived as greater than the utility gain associated with receiving the good, causing a preference for one’s current endowments and resulting in consumers who rather stick to their status quo than switch to an alternative (Kahneman, Knetsch, & Thaler, 1990; Kahneman & Tversky, 1979; Knetsch, 1995). A broader perspective on loss aversion or the endowment effect may lead to consumer food habits being considered as a preference for the status quo type of food intake (Samuelson & Zeckhauser, 1988). This may lead to the prevalence of a lifestyle which is then difficult to change. This thesis describes several experiments to understand the impact of reference effects in consumer decision making with respect to hedonic versus utilitarian food products. Two basic consumption effects: (1) consummatory affective (hedonic) gratification from sensory attributes, and (2) instrumental, utilitarian functions or consequences of consumption (Batra & htola, 1991; Dhar & Wertenbroch, 2000; Hirschman & Holbrook, 1982) suggest that some types of food choices might also be more susceptible to loss aversion or status quo effects than other types. In experimental classroom settings, participants (16-18 years old) received either a hedonic or a utilitarian type of food product and made a decision between keeping their endowment or exchanging it for the other type of food. The outcomes of the experiments showed that the endowment effect was significantly stronger for hedonic than for utilitarian food products. Also, the strong influence of the hedonic value difference in the choice of hedonic food products was shown which was consistent with our assumption predicting different endowment effects for the two goods. Basically, there are two different ways in which consumers can make decisions: by reasoning and by using emotions or cues. A few additional experiments focused on the effects of cognitive constraints on food choices. Cognitive constraints tend to reduce consumers’ attention to the food choice process such as in the process of a food habit. The outcomes of two experiments showed that the endowment effect was significantly stronger under cognitive constraint than without constraint, which was consistent with our assumption. In addition, the influence of cognitive constraints on consumer choices was significantly stronger for hedonic than for utilitarian food items. Being forced to rely on a more intuitive type of decision making, in case of distractions, increased the endowment effect of specifically hedonic food products. Although there is some agreement on the influence of gender in different consumer decision domains like verbal or analytic skills, consumption or investments, there is still much unknown about the meaning of gender differences in consumer food choices. Males more often than females use the intuitive mode of processing, whereas females on the other hand, are more likely to use a detailed analytic processing mode (Kempf, Palan, & Laczniak, 1997; Meyers-Levy, 1989; Meyers-Levy & Maheswaran, 1991). Comparisons across the cognitive load conditions showed that girls’ endowment effects, independent of product type and in case of a hedonic good in endowment, were significantly stronger when they experienced cognitive constraints, compared to the unconstrained case. A stronger preference for hedonic goods in the choice condition, in addition to the finding that cognitive constraints did not influence the endowment effects for boys suggests that a heuristic processing style seemed indeed most appropriate for boys’ food choices. Because losses are considered as more painful than the same gain provides pleasure, choice preferences may change subject to whether they are experienced in the loss or gain domain of the value function (Knetsch, 2001). Providing information about positive or negative aspects of choice alternatives may result in a change of the reference point of evaluation resulting in preference reversals and leading to, for example, less strong ‘want’ preferences. In addition, focusing on the alternative instead of the status quo in choice situations may increase the attractiveness of the alternative and consequently lead to preference reversals for both goods (Tversky & Kahneman, 1991). The results of the experiments showed that message framing influenced the status quo bias for a hedonic food product leading to a healthier food choice. When participants were asked to retrieve information about the goods from their own memory, the effect on product choice was relatively strong. Especially preferences to keep a Mars bar in endowment decreased when the focus of attention was on including an apple in one’s consumption pattern. A final study was designed to test the endowment effect on food product bundles to relate endowment effects of single food products to food portfolios and food consumption patterns. The results showed that endowment effects significantly decreased when an extra choice option was introduced to keep one of the two goods and exchange the other item confirming our assumptions. In addition, giving up on only one good required less willpower compared to giving up on two goods. A probit regression analysis showed that when participants indicated that their choice was driven by their emotions and heart, indicating impulsiveness, they were more inclined to keep both goods in endowment, whereas desire for variety did not significantly influence their choice. Although many aspects related to reference effects and consumer food choice are worthwhile to investigate further, the outcomes of this thesis might already be useful in attempts to influence consumers’ unhealthy food choices. Endowment effects may be important in establishing a status quo bias for an unhealthy food consumption pattern. A more intuitive type of reasoning leads to stronger endowment effects for especially hedonic goods. Distractions in everyday life may lead to more intuitive decision processes. Outcomes of several experiments suggested that it might be useful to take unconscious processes such as reference effects into account when changing consumer preferences. In addition it might be interesting to focus on the magnitude of the change. Changing consumer food choices is difficult, but findings presented in this thesis indicated that reference effects might be useful to include in this process. <br/

Rural Household Food Consumption in China: Evidence from the Rural Household Survey

Food Consumption/Nutrition/Food Safety,

BOOTSTRAPPING IN VECTOR AUTOREGRESSIONS: AN APPLICATION TO THE PORK SECTOR

Standard bootstrap method is used to generate confidence intervals (CIs) of impulse response functions of VAR and SVAR models in the pork sector. In the VAR model, the bootstrap method does not produce significant different results from Monte Carlo simulations. In the SVAR analysis, on the other hand, the bootstrap CIs are significantly different from Monte Carlo CIs after a six period forecast intervals. This suggests that the choice of method used to measure reliability of IRFs is not trivial. Furthermore, bootstrap CIs in SVAR model seem to be more stable than MC CIs, which tend to be wider in the longer horizons.Research Methods/ Statistical Methods,

Hamster-to-rat heart and liver xenotransplantation with FK506 plus antiproliferative drugs

Heterotopic hamster hearts transplanted to unmodified LEW rats underwent humoral rejection in 3 days. Survival was prolonged to a median of 4 days with 2 mg/kg/day FK506. As monotherapy, 15 mg/kg/day cyclophosphamide greatly prolonged graft survival-far more than could be accomplished with RS-61443, brequinar (BQR), mizoribine, methotrexate, or deoxyspergualin. However, when FK506 treatment, which was ineffective alone, was combined with a short induction course (14 or 30 days) of subtherapeutic BQR, RS-61443, or cyclophosphamide, routine survival of heart xenografts was possible for as long as the daily FK506 was continued. In addition, a single large dose of 80 mg/kg cyclophosphamide 10 days preoperatively allowed routine cardiac xenograft survival under FK506. The ability of these antimetabolites to unmask the therapeutic potential of FK506 correlated, although imperfectly, with the prevention of rises of preformed heterospecific cytotoxic antibodies immediately postoperatively. As an adjunct to FK506, azathioprine was of marginal value, whereas mizoribine, methotrexate, and deoxyspergualin (DSPG) were of intermediate efficacy. After orthotopic hepatic xenotransplantation, the perioperative survival of the liver with its well-known resistance to antibodies was less dependent than the heart on the antimetabolite component of the combined drug therapy, but the unsatisfactory results with monotherapy of FK506, BQR, RS-61443, or cyclophosphamide were changed to routine success by combining continuous FK506 with a short course of any of the other drugs. Thus, by breaking down the antibody barrier to xenotransplantation with these so-called antiproliferative drugs, it has been possible with FK506 to transplant heart and liver xenografts with consistent long-term survival of healthy recipients