Universal spectra of random Lindblad operators

To understand typical dynamics of an open quantum system in continuous time, we introduce an ensemble of random Lindblad operators, which generate Markovian completely positive evolution in the space of density matrices. Spectral properties of these operators, including the shape of the spectrum in the complex plane, are evaluated by using methods of free probabilities and explained with non-Hermitian random matrix models. We also demonstrate universality of the spectral features. The notion of ensemble of random generators of Markovian qauntum evolution constitutes a step towards categorization of dissipative quantum chaos.Comment: 6 pages, 4 figures + supplemental materia

Keeping calm in the face of change: towards optimisation of FRP by reasoning about change

Functional Reactive Programming (FRP) is an approach to reactive programming where systems are structured as networks of functions operating on signals (time-varying values). FRP is based on the synchronous data-flow paradigm and supports both (an approximation to) continuous-time and discrete-time signals (hybrid systems).What sets FRP apart from most other languages for similar applications is its support for systems with dynamic structure and for higher-order reactive constructs. This paper contributes towards advancing the state of the art of FRP implementation by studying the notion of signal change and change propagation in a setting of structurally dynamic networks of n-ary signal functions operating on mixed continuous-time and discrete-time signals. We first define an ideal denotational semantics (time is truly continuous) for this kind of FRP, along with temporal properties, expressed in temporal logic, of signals and signal functions pertaining to change and change propagation. Using this framework, we then show how to reason about change; specifically, we identify and justify a number of possible optimisations, such as avoiding recomputation of unchanging values. Note that due to structural dynamism, and the fact that the output of a signal function may change because time is passing even if the input is unchanging, the problem is significantly more complex than standard change propagation in networks with static structure

The Kochen - Specker theorem in quantum mechanics: a philosophical comment (part 1)

Non-commuting quantities and hidden parameters – Wave-corpuscular dualism and hidden parameters – Local or nonlocal hidden parameters – Phase space in quantum mechanics – Weyl, Wigner, and Moyal – Von Neumann’s theorem about the absence of hidden parameters in quantum mechanics and Hermann – Bell’s objection – Quantum-mechanical and mathematical incommeasurability – Kochen – Specker’s idea about their equivalence – The notion of partial algebra – Embeddability of a qubit into a bit – Quantum computer is not Turing machine – Is continuality universal? – Diffeomorphism and velocity – Einstein’s general principle of relativity – „Mach’s principle“ – The Skolemian relativity of the discrete and the continuous – The counterexample in § 6 of their paper – About the classical tautology which is untrue being replaced by the statements about commeasurable quantum-mechanical quantities – Logical hidden parameters – The undecidability of the hypothesis about hidden parameters – Wigner’s work and и Weyl’s previous one – Lie groups, representations, and psi-function – From a qualitative to a quantitative expression of relativity − psi-function, or the discrete by the random – Bartlett’s approach − psi-function as the characteristic function of random quantity – Discrete and/ or continual description – Quantity and its “digitalized projection“ – The idea of „velocity−probability“ – The notion of probability and the light speed postulate – Generalized probability and its physical interpretation – A quantum description of macro-world – The period of the as-sociated de Broglie wave and the length of now – Causality equivalently replaced by chance – The philosophy of quantum information and religion – Einstein’s thesis about “the consubstantiality of inertia ant weight“ – Again about the interpretation of complex velocity – The speed of time – Newton’s law of inertia and Lagrange’s formulation of mechanics – Force and effect – The theory of tachyons and general relativity – Riesz’s representation theorem – The notion of covariant world line – Encoding a world line by psi-function – Spacetime and qubit − psi-function by qubits – About the physical interpretation of both the complex axes of a qubit – The interpretation of the self-adjoint operators components – The world line of an arbitrary quantity – The invariance of the physical laws towards quantum object and apparatus – Hilbert space and that of Minkowski – The relationship between the coefficients of -function and the qubits – World line = psi-function + self-adjoint operator – Reality and description – Does a „curved“ Hilbert space exist? – The axiom of choice, or when is possible a flattening of Hilbert space? – But why not to flatten also pseudo-Riemannian space? – The commutator of conjugate quantities – Relative mass – The strokes of self-movement and its philosophical interpretation – The self-perfection of the universe – The generalization of quantity in quantum physics – An analogy of the Feynman formalism – Feynman and many-world interpretation – The psi-function of various objects – Countable and uncountable basis – Generalized continuum and arithmetization – Field and entanglement – Function as coding – The idea of „curved“ Descartes product – The environment of a function – Another view to the notion of velocity-probability – Reality and description – Hilbert space as a model both of object and description – The notion of holistic logic – Physical quantity as the information about it – Cross-temporal correlations – The forecasting of future – Description in separable and inseparable Hilbert space – „Forces“ or „miracles“ – Velocity or time – The notion of non-finite set – Dasein or Dazeit – The trajectory of the whole – Ontological and onto-theological difference – An analogy of the Feynman and many-world interpretation − psi-function as physical quantity – Things in the world and instances in time – The generation of the physi-cal by mathematical – The generalized notion of observer – Subjective or objective probability – Energy as the change of probability per the unite of time – The generalized principle of least action from a new view-point – The exception of two dimensions and Fermat’s last theore

Here and Nowhere.The Making of Urban Space

My interest is in the conscious role of space and time or of geography and history in contemporary urban development, particularly in the generation of urban projects. Can urban development be seen in relationship to form and thus to urban projects that are shaping and being shaped by contemporary culture? I would like to draw attention to a shift of attitude in a series of urban projects within the field of architecture and urbanism based on a ‘more fluid and kaleidoscopic socio-economic landscape’ that is characterised by programmatic indeterminacy and instability. This parallels a shift in society: The fragmenting of centralised flows of power towards the power of flows induced by networks that become the dominant social morphology (Castells 1996). I then introduce the notion of a material culture based on object form and the production and consumption of form through complex processes of negotiation. This negotiation of form is increasingly a conscious process on the level of configuration, a conceptual and diagrammatic level within the design process between the virtual and the real that allows interaction and participation. This in turn refers to the notion of the deleuzian abstract machines in cultural and historical processes and evolution in general. Geography has created GIS (Geographical Information Systems), a digital tool with which we within the diagrammatic process of configuration can create any map and map anything, an interface for participatory action. What is the historical equivalent of this tool, which are the generative engines of change over time and how are they configured

A very modern professional: the case of the IT service support worker

The IT profession has retained a reputation as a ‘privileged area of the labour market’ (Webster, 2005, p.4; Bannerji, 2011). Workers practicing IT skills have been at the forefront of the competitive drive for innovation and efficiency gains promoted by a neoliberal enterprise ideology (Blackler et al, 2003). In the last two decades, as systems thinking (e.g. Ackoff, 1999) and customer-centric practices (e.g. Levitt, 2006) have converged in a globally powerful IT service management (ITSM) ‘best practice’ discourse (Trusson et al, 2013), the IT service support worker has emerged to be a worker-type of considerable socio-economic importance. Aside from keeping organizational information systems operative, when such systems fail these workers are called upon to rapidly restore the systems and thus head-off any negative commercial or political consequences. Yet these workers are acknowledged only as objectified resources within the ITSM ‘best practice’ literature (e.g. Taylor, Iqbal and Nieves, 2007) and largely overlooked as a distinctive contemporary worker-type within academic discourse. This paper, through analysis of salary data and qualitative data collected for a multiple case study research project, considers the extent to which these workers might be conceived of as being ‘professionals’. The project approached the conceptual study of these workers through three lenses. This paper focuses on the project’s consideration of them as rationalised information systems assets within ‘best practice’ ITSM theory. It also draws upon our considerations of them as knowledge workers and service workers. We firstly situate the IT service support worker within a broader model of IT workers comprising four overlapping groupings: managers, developers, technical specialists and IT service support workers. Three types of IT service support worker are identified: first-line workers who routinely escalate work; second-line workers; and ‘expert’ single-line workers. With reference to close associations made with call centre workers (e.g. Murphy, 2011) the status of IT service support workers is explored through analysis of: (i) salary data taken from the ITJOBSWATCH website; and (ii) observational and interview data collected in the field. From this we challenge the veracity of the notion that the whole occupational field of IT might be termed a profession concurrently with the notion that a profession implies work of high status. Secondly, the paper explores two forces that might be associated with the professionalization of IT as an occupation: (i) rationalisation of the field (here promoted by the British Computer Society); and (ii) formalisation of IT theoretical/vocational education. A tension is identified, with those IT service support workers whose work is least disposed to rationalisation and whose complex ‘stocks of knowledge’ (Schutz, 1953) have been acquired through time-spent practice laying claim to greater IT professional status. Thirdly, consideration is given to individuals’ personal career orientations: occupational, organizational and customer-centric (Kinnie and Swart, 2012). We find that whilst organizations expect IT service support workers to be orientated towards serving the interests of the organization and its clients, the most individualistically professional tend towards being occupationally orientated, enthusiastically (re)developing their skills to counter skills obsolescence in an evolving technological arena (Sennett, 2006)

THE RIGHT INFORMATION IN THE RIGHT PLACE AT THE RIGHT TIME: PRECISION AND MULTIPLICITY IN MEDICAL PRACTICES

Does the quest for ‘the right information in the right place at the right time’ create a blind spot in development and implementation of ICT support for complex work practices by spurring wild-goose-chases for ‘the one, right representation’? Could resources be spent more fruitfully by shifting focus towards the multiplicities of information practices in such settings, and how to support rather than attempting to obliterate them? Based on the study of a hospital ICT implementation, this paper challenges the notion of a singular and linear precision. Illustrated by the measuring and (re)presentation of blood pressure, precision emerges as a multiplicity, enacted in different socio-material practices; blood pressure is not only a function of how it is produced, but also of the diverse purposes it serves. It is argued that this should have implications for how we think about information and its representations in all phases of the system lifecycle

The Ghoul Box: An Affective Ecopoetics of The Anthropocene

The Ghoul Box is a collection of poetry which explores the complex entanglements and affects of the Anthropocene – a proposed geological age defined by the impact of human activity on the global climate and the biosphere. The collection strives to convey a sense of anxiety related to our increasingly fraught relationship with the environment and a pervasive sense of crisis, while exploring the sources of this anxiety. My reflective essay discusses the development of my collection from my initial interest in shifting concepts of nature and ecology towards a more experimental exploration of energy, complexity, chaos, assemblage, and self-organization. I interrogate ideas of environmental melancholia, negative capability, and affective ecopoetic techniques. My research of nature poetry, environmental poetry, and ecopoetry informed the development of my collection, and I examine this impact at length. The Anthropocene is a relatively recent concept but one with increasing influence. My poetry collection addresses the notion of complex interconnections across time and space, between the local and the universal, the personal and the social, through the frame of the Anthropocene. It offers a new perspective on our modern age – one which mingles memory and myth with technological mediation and immediate experience to form a novel image of our contemporary environmental and existential crisis

Reinforcement learning control of a biomechanical model of the upper extremity

Among the infinite number of possible movements that can be produced, humans are commonly assumed to choose those that optimize criteria such as minimizing movement time, subject to certain movement constraints like signal-dependent and constant motor noise. While so far these assumptions have only been evaluated for simplified point-mass or planar models, we address the question of whether they can predict reaching movements in a full skeletal model of the human upper extremity. We learn a control policy using a motor babbling approach as implemented in reinforcement learning, using aimed movements of the tip of the right index finger towards randomly placed 3D targets of varying size. We use a state-of-the-art biomechanical model, which includes seven actuated degrees of freedom. To deal with the curse of dimensionality, we use a simplified second-order muscle model, acting at each degree of freedom instead of individual muscles. The results confirm that the assumptions of signal-dependent and constant motor noise, together with the objective of movement time minimization, are sufficient for a state-of-the-art skeletal model of the human upper extremity to reproduce complex phenomena of human movement, in particular Fitts' Law and the 2/3 Power Law. This result supports the notion that control of the complex human biomechanical system can plausibly be determined by a set of simple assumptions and can easily be learned.Comment: 19 pages, 7 figure

Evolution and complexity: the double-edged sword

We attempt to provide a comprehensive answer to the question of whether, and when, an arrow of complexity emerges in Darwinian evolution. We note that this expression can be interpreted in different ways, including a passive, incidental growth, or a pervasive bias towards complexification. We argue at length that an arrow of complexity does indeed occur in evolution, which can be most reasonably interpreted as the result of a passive trend rather than a driven one. What, then, is the role of evolution in the creation of this trend, and under which conditions will it emerge? In the later sections of this article we point out that when certain proper conditions (which we attempt to formulate in a concise form) are met, Darwinian evolution predictably creates a sustained trend of increase in maximum complexity (that is, an arrow of complexity) that would not be possible without it; but if they are not, evolution will not only fail to produce an arrow of complexity, but may actually prevent any increase in complexity altogether. We conclude that, with regard to the growth of complexity, evolution is very much a double-edged sword