Quantum Simulation Logic, Oracles, and the Quantum Advantage

Query complexity is a common tool for comparing quantum and classical computation, and it has produced many examples of how quantum algorithms differ from classical ones. Here we investigate in detail the role that oracles play for the advantage of quantum algorithms. We do so by using a simulation framework, Quantum Simulation Logic (QSL), to construct oracles and algorithms that solve some problems with the same success probability and number of queries as the quantum algorithms. The framework can be simulated using only classical resources at a constant overhead as compared to the quantum resources used in quantum computation. Our results clarify the assumptions made and the conditions needed when using quantum oracles. Using the same assumptions on oracles within the simulation framework we show that for some specific algorithms, like the Deutsch-Jozsa and Simon's algorithms, there simply is no advantage in terms of query complexity. This does not detract from the fact that quantum query complexity provides examples of how a quantum computer can be expected to behave, which in turn has proved useful for finding new quantum algorithms outside of the oracle paradigm, where the most prominent example is Shor's algorithm for integer factorization.Comment: 48 pages, 46 figure

Coping with Heterogeneities in the Difference in Differences Design

Carling, Holmlund and Vejsiu reported in the October 2001 issue of the Economic Journal that a cut in the unemployment insurance replacement rate from 80 to 75 percent caused a 10 percent increase in the job finding rate. They also identify an anticipatory reform effect up to five months before the reform. Implied elasticity at 1,6 is high compared to previous research in Sweden and elsewhere. After analysing their data for various heterogeneities, we conclude that the estimated coefficients designed to capture the reform and the anticipatory effects are statistical artefacts. The standard statistical tests and analytic procedures used by CHV do not warn for this eventuality.Heterogeneities; Difference in differences design; Unemployment insurance; Unemployment compensation

Spin transport in ferromagnetic/normal-metal tunnel junction arrays

An array of alternating ferromagnetic and normal-metal islands separated by small tunnel junctions is theoretically investigated in the sequential tunneling regime. A numerical Monte Carlo method is used to calculate the transport properties. The spin-dependent tunneling currents give rise to nonequilibrium spin accumulation on the normal island. The tunneling magneto resistance (TMR) is calculated for a large range of array parameters. The TMR oscillates with bias voltage and can become negative for certain array parameters. We show that the long-range electrostatic interaction in the arrays can significantly increase the TMR; for experimentally accessible parameters the magnitude of the TMR can be as large as 100%

Seeing all things in space : Kant and the reality of space in the context of early modern philosophy

One of the basic concepts of the metaphysics of the pre-critical Kant is the early modern, Leibnizian concept of the world as a synthetic whole of simple substances. Space is the order according to which these simple substances coexist, in the presence of God. Kant’s turn to critical philosophy contained a re-evaluation of Leibnizian metaphysics. Space is an ideal form of sensibility, not a real order of coexisting simple substances. This dissertation argues that Kant’s critical turn inspired him to outline a new science of subjective space – the Transcendental Aesthetic. Leibnizians argued that our knowledge of space is innate, but still abstracted from the common sense idea of extension. In the Critique of Pure Reason Kant responded that this misrepresents our knowledge of the subjective space, which is the topic of the Transcendental Aesthetic. An exposition of the marks of the concept of subjective space not only shows that space is a form of sensibility, but that it is a continuous, actually infinite whole, which precedes its potentially infinite parts. In Kant’s terminology space is an analytic whole, which gives a key to the ideality of space, according to this dissertation. One important topic in the literature concerns Kant’s awareness of the Leibnizian alternative that space might be both a form of sensibility and an order of coexistence. This dissertation claims that Kant could not rule out this alternative completely. However, in one aspect, Kant was successful: Leibnizians had to admit that continuity belongs to space, not as an order of coexistence, but as a form of sensibility. We see all things in continuous space, not in God. However, seeing things in space is analogous to seeing them in God.Kantin niin sanotun esikriittisen metafysiikan yksi leibnizilaisista peruskäsityksistä on, että maailma on yksinkertaisten substanssien muodostama synteettinen kokonaisuus. Tässä näkemyksessä avaruus on järjestys, jonka mukaisesti yksinkertaiset substanssit ovat yhdessä olemassa Jumalan läsnäollessa. Kantin kriittiseen filosofiaan sisältyy leibnizilaisen metafysiikan uudelleen arviointi. Sen sijaan, että avaruus olisi yhdessä olemassa olevien yksinkertaisten substanssien reaalinen järjestys, avaruus on aistimellisuuden ideaali muoto. Tässä väitöskirjassa esitetään, kuinka Kantin kriittinen käänne sai hänet hahmottelemaan uuden subjektiivisen avaruuden tieteen – transsendentaalisen estetiikan. Leibnizilaiset väittivät, että tietomme avaruudesta on sisäsyntyistä, joskin abstrahoitu arkiajatteluunkin kuuluvasta ulotteisuuden ideasta. Puhtaan järjen kritiikissä Kant puolestaan väittää, että leibnizilaiset vääristävät tietomme subjektiivisesta avaruudesta, joka on aiheena transsendentaalisessa estetiikassa. Subjektiivisen avaruuden käsitteen erittely osoittaa, että avaruus on paitsi aistimellisuuden muoto, myös jatkuva, aktuaalisesti ääretön kokonaisuus, joka edeltää sen potentiaalisesti äärettömiä osia. Kantin terminologiassa avaruus on analyyttinen kokonaisuus, joka tässä väitöskirjassa esitetyn perusteella toimii avaimena avaruuden ideaalisuuteen. Tutkimuskirjallisuudessa tärkeä aihe on, miten tietoinen Kant oli leibnizilaisesta vaihtoehdosta, että avaruus saattaisi olla sekä aistimellisuuden muoto että yhdessä olemisen järjestys. Tässä väitöskirjassa esitetään, ettei Kant voinut kokonaan sulkea pois tätä vaihtoehtoa. Yhdessä mielessä Kant kuitenkin onnistui: leibnizilaiset olivat pakotettuja myöntämään, että jatkuvuus kuuluu avaruuteen aistimellisuuden muotona eikä yhdessä olemisen järjestyksenä. Näemme kaikki oliot jatkumollisessa avaruudessa, emme Jumalassa. Niiden näkeminen avaruudessa on kuitenkin analogista niiden näkemiselle Jumalassa

Didactic and Curriculum in ECEC from a Froebelian standpoint

How can we use Friedrich Froebel’s play theory in order to analyze ECEC, Early Childhood Education and Care? Wolfgang Klafki builds his theory of categorical Bildung on Froebel’s play theory, which presupposes the interaction between child, adult and content, as in the didactic triangle. Froebel’s play theory was lost in the hands of his followers Bertha von Marenholtz-Bülow and Henriette Schrader-Breymann. Developmental theories such as the cultural level theory and the recapitulation theory had a strong influence. One result was a child-centered laissez-faire pedagogy, waiting for the child to mature enough to be able to start school. With Klafki and his perspective on Froebel, it is possible to ask a set of questions in order to describe and analyze contemporary ECEC programs: (i) What are the didactic relations between child, adult and content, as in the didactic triangle? (ii) What is the content and how is it selected and organized? (iii) What kind of play and learning is intended

Researching ‘with’ not ‘on’: Engaging Foundation GNVQ students in the research process - emerging themes from the study

This paper discusses practical and methodological issues arising from ongoing case study research exploring the hopes, aspirations and learning identity of 4 cohorts of GNVQ Foundation (level 1) students in 2 English General Further Education (FE) colleges. This paper focuses on work with the student participants in the study and poses a number of questions. How can young people be engaged with a research process? How can that process be meaningful to them in the context of their lives and experiences? How can the significant ethical issues involved with working with these students be addressed? Part of the thesis for this work has been the lack of value placed on students enrolled on Foundation level programmes. Therefore, it was important to demonstrate value for them throughout this process, and one way in which this was achieved was by engaging the young people with the research process as actively as possible. Working within a Social Justice theoretical framework, and specifically considering the notion of knowledge/power relationships the paper outlines the participative approach which was taken in the development of interview questions, informed by the ‘arenas of action and centres of choice’ described by Ball et. al (2000:148). Further, it explores the practical issues and ethical tensions which arose associated with respecting the young people and facilitating their involvement in the research process whilst working within the constraints placed by their level of experience and understanding, and discusses some of the unanticipated challenges that arose from this process. The paper concludes with a discussion of the way the research has evolved in response to these issues and of the ‘added value’ to the research which has arisen from the participants’ engagement with the process

Permanence of Carbon Sequestered in Forests under Uncertainty

In this paper we examine the issue of permanence in the context of sequestering carbon through afforestation. We develop a dynamic nested optimal control model of carbon sequestration associated with the decision to afforest a tract of land given there are uncertainties associated with fire and insect/disease hazards. Conceptually, these potential hazards are similar in that their occurrence at any time t is uncertain and landowners can take specific actions – although generally different actions - in any time period t to reduce the probability of sustaining losses related to them. The hazards differ, however, in that fire represents a large loss in carbon at a moment in time, while insect/disease infestations are more likely to be reflected in a period of significant slowing of the rate of carbon accumulation than was anticipated followed by a sustained period of slowly decreasing carbon losses. The nature of these losses will influence the design of incentives under GHG mitigation frameworks that require carbon losses to be replaced as well as the strategies farmers adopt to deal with the uncertainties associated with these events occurring.carbon sequestration, uncertainty, optimal control, hazard function, forestry, permanence, Environmental Economics and Policy, Land Economics/Use,