An atomic magnetometer is a sensor which is used to measure a magnetic field through its interaction with the atomic sample. Significant research into atomic magnetometry has led to the development of very sensitive atomic sensors capable of matching the sensitivity of the most sensitive magnetometers, superconducting quantum interference devices (SQUIDs). Because SQUIDS require cryogenics to operate, atomic magnetometers provide a sensitive, yet low-cost alternative. They have found use in many areas such as medicine, security, explosives detection and fundamental physics research. One of the primary factors influencing sensitivity is the detuning of the probe beam from the resonant transitions of the atomic ground state. A caesium room temperature radio-frequency (rf) magnetometer is constructed and used to investigate the influence of the probe beam detuning on the magnetometer signal of the F = 3 and F = 4 ground states. The results of probing near and far from resonance revealed an off-resonant regime and two absorptive regimes. In the off-resonant regime, the atomic spins are unperturbed by the probe beam; it is a quantum non-demolition (QND) interaction. The two absorptive regimes, found when the probe beam is in the vicinity of either the 62S1 2 F = 3 → 6 2P3 2 F 0 = 2,3,4 or the 62S1 2 F = 4 → 6 2P3 2 F 0 = 3,4,5 transitions, is characterised as a non-QND interaction in which the probe beam influences the measurement. The sensitivity of the rf magnetometer is determined to be ≈ 1.98 fT/ √ Hz. In addition, the exploration of the relationship between the signal to noise ratio (SNR) and probe beam detuning revealed that the SNR is constant with detuning but the larger the detuning, the higher the probe beam power needs to be to reach the optimum SNR.

Two searches for Beyond Standard Model resonances are performed using 13 TeV proton–proton collision data collected by the ATLAS detector in 2015 and 2016 using the invariant mass distribution of pairs of jets, where at least one or both jets are identified as containing a b-quark. The searches are sensitive to resonances decaying to a pair of b-quarks or a b-quark and a gluon. A high-mass search probes the mass region 1.4 – 6 TeV using a data-set corresponding to an integrated luminosity of 13.3 fb−1. A low-mass search utilises real-time b-jet identification to probe the mass region 0.6 – 1.5 TeV using a data- set corresponding to an integrated luminosity of 24.3 fb−1. No evidence of a resonance is found. Excited b∗ quarks with masses from 1.4 to 2.3 TeV and a set of Z′ boson models with masses from 0.6 to 1.25 TeV or at 1.5 TeV are excluded at the 95% credibility-level. In addition, 95% credibility-level upper limits are set on generic signals with a Gaussian distribution in the mass range 0.65 – 6 TeV.

The following thesis presents the result of a Beyond the Standard Model search for heavy resonances (V'/A) decaying into a Standard Model W or Z boson, and a Higgs (h) boson with a final state signature llbb̄, lνbb̄, or ννbb̄, where l= e/μ , in proton-proton collisions at a center of mass energy of √s = 13 TeV. The data is collected using the ATLAS detector at the Large Hadron Collider, during the data periods of 2015+2016, amounting to 36.1 fb^{-1}. The search is conducted using the (transverse) invariant mass spectrum of the reconstructed Standard Model W/Z boson and Higgs boson system, W/Z + h, to search for excesses using the CL_{s} binned profile likelihood test statistic. No excess is observed, therefore the results are interpreted in terms of constraints on σ_{V/A} × BR(h→bb̄), for heavy vector bosons predicted by Heavy Vector Triplet models (HVT ), W'/Z', or the CP-odd scalar boson A predicted by Two-Higgs Doublet Models (2HDM ). The upper limits on the production cross-sections are then used to assign constraints to the model parameter space. For the HVT interpretation, limits on two benchmark models corresponding to fermiophobic and fermiophilic extensions, labelled A and B, of the heavy resonances are set: m_{V'} = 2800(2930) GeV. For 2HDMs, limits on the production cross-section for mediator masses ranging from 220-2000 GeV are set: 5.5 × 10^{−3} pb → 2.4 × 10^{−1} pb for gg→A production, and 3.4 × 10^{−3} → 7.3 × 10^{−1} pb for bbA associated production.

The majority of biology can be adequately described by classical laws, yet there are suggestions that a variety of organisms may harness non-trivial quantum phenomena to gain a biological advantage. This thesis is concerned with the light induced dynamics in photosynthetic light harvesting antennae. Quantum coherences persisting on picosecond time-scales have been repeatedly observed in a variety of species. This ran contrary to the prevailing theories of energy transfer dynamics in these systems. A consensus has emerged that a delicate competition between electronic and vibrational interactions is responsible for prolonging coherences between electronic states of chromophores. In particular, interactions with specific under-damped vibrational modes are known to play a fundamental role. This thesis demonstrates that room temperature, efficient vibration-assisted energy transfer in a biologically relevant exciton-vibration dimers can manifest and benefit from non-classical fluctuations of collective pigment motions. The inadequacy of a classical description of selected vibrations is further illustrated by identifying features of electronic dynamics that are enhanced by quantum properties. A quan\-tum-thermo\-dynamical form\-alism describing heat and work fluxes between partitions of a closed quan\-tum system is extended to open quan\-tum systems in the non-per\-turb\-ative regime. This reveals non-trivial relations between the electronic interactions among chromophores and the relative contribution of work- and heat-like energy fluxes between electronic and vibrational motions. This in turn highlights relations between structure and energy transformations in photosynthetic complexes. Finally, the thesis investigates energy transfer within and between antennae of purple bacteria acclimated to different illumination conditions. The protein composition is altered depending on the light levels. Consequently, the electronic energy landscape is modified to accelerate intra-complex energy transfer without detriment to inter-complex transfer, thereby promoting or diminishing resonances with specific vibrational motions. This suggests that acclimation may serve to exploit non-trivial quantum phenomena.

This thesis comprises an interdisciplinary examination of the phenomenon of scientific classification. The major aims of the thesis are two-fold: To show that scientific classification comprises a mixture of metaphysics and epistemology. To illustrate that the psychological explanation-based account of categorisation is an appropriate model for scientific as well as for lay classification. I begin by characterising the doctrine of Objectivism which provides the philosophical backdrop for traditional accounts of categorisation in both philosophy and psychology. I illustrate some of the shortcomings of Objectivism and propose an alternative doctrine in its place - internal or experimental realism. This alternative doctrine forms the philosophical backdrop for my own account of (scientific) classification. Next, I provide a short history of theories in the psychology of categorisation. I argue that there has been a shift from very tightly defined, inflexible and context-insensitive accounts (the classical view) to much more flexible, context-sensitive and human-oriented accounts (the explanation-based view). I go on to examine the criticisms which an objectivist philosopher, Georges Rey, has levied against work in the psychology of categorisation. I then put forward for my own positive account of scientific classification. This incorporates a number of claims: that classification involves more than a reflection of metaphysics, that human beings (and so epistemology) make an active contribution to the classificatory process, that the dividing line between metaphysics and epistemology is blurred, that there are problems with applying the objectivist doctrine of essentialism to scientific classification and as a result of the foregoing points, that the explanation-based account of categorisation is a suitable model of classification by scientific experts. The material which I use in support of these claims comes from three case studies in the history and sociology of science and from a number of philosophical arguments.

This thesis presents a detailed account of what printworkers know, the way in which they know it, and what they do with that knowledge in order for production to happen : the substantive and cognitive content of print knowledge, its distribution and mobilisation. It looks at everyday industrial practice in terms more usually reserved for the knowledge of scientists, engineers or other professionals, and finds that they are also useful for characterising the substantive and cognitive content of knowledge used in a largely "blue-collar" manufacturing environment. Drawing on work from the sociology of scientific knowledge, the history and sociology of science and technology, and other relevant fields, the thesis reviews existing frameworks for conceptualising and analysing knowledge and practice, and the power relations inherent therein. It discusses the applicability (and limitations) of these frameworks to current everyday manufacturing production activity in the light of the empirical data, in order to increase understanding of technological knowledge and practice. Fieldwork was carried out in three firms in different sectors of the industry, using a variety of data collection methods including interviews, participant observation and action research/consultancy. Data are presented ethnographically, in the form of case studies. The thesis argues that social, economic, technical and political factors both structural and local shape the content and distribution of print knowledge and power within and between firms, creating both the industry's established technological communities and its day-to-day technological networks. It suggests that there are two main types of mobilisation process in print production, recursively related through institutionalisation : DEFINITION, when "common knowledge" is mobilised by individuals who belong to a technological community; and PROBLEM-SOLUTION, which requires the "collective mobilisation" of diverse personal knowledge (underpinned by common knowledge) by technological networks of heterogeneous composition. The non-human world, in the form of texts, tools and machines, is crucial to both processes and to the relation between them.

北海道大学 / 博士 / 工学

北海道大学 / 博士 / 工学

北海道大学 / 博士 / 工学

北海道大学 / 博士 / 工学