Collective decoherence of cold atoms coupled to a Bose-Einstein condensate

We examine the time evolution of cold atoms (impurities) interacting with an environment consisting of a degenerate bosonic quantum gas. The impurity atoms differ from the environment atoms, being of a different species. This allows one to superimpose two independent trapping potentials, each being effective only on one atomic kind, while transparent to the other. When the environment is homogeneous and the impurities are confined in a potential consisting of a set of double wells, the system can be described in terms of an effective spin-boson model, where the occupation of the left or right well of each site represents the two (pseudo)-spin states. The irreversible dynamics of such system is here studied exactly, i.e. not in terms of a Markovian master equation. The dynamics of one and two impurities is remarkably different in respect of the standard decoherence of the spin-boson system. In particular, we show: (i) the appearance of coherence oscillations, (ii) the presence of super and subdecoherent states that differ from the standard ones of the spin-boson model, and (iii) the persistence of coherence in the system at long times. We show that this behaviour is due to the fact that the pseudospins have an internal spatial structure. We argue that collective decoherence also prompts information about the correlation length of the environment. In a one-dimensional (1D) configuration, one can change even more strongly the qualitative behaviour of the dephasing just by tuning the interaction of the bath.

Premiere of "Spaced Images with Noise and Lines" Performance at the Joinery, Dublin, at at Spatial Music Collective concert. Authors: Lyon, E. Keywords: (Spatial Audio, Electroacoustic Music, Computer Music, Algorithmic Music) Publication date: 07 Oct 2011

Performance at the Joinery, Dublin, at at Spatial Music Collective concert

Web-based social movements contesting marketing strategy: Mobilization of multiple actors and rhetorical strategies

Previous studies suggest that marketing strategy is developed and used to mobilise and configure the actions of firm actors, creating a set of stabilising activities focused on the firm–customer dyad. Destabilising forces precipitated by the Internet and associated digital technologies involving contention and disruption by multiple actors are much less prevalent in the marketing literature. The central point we advance is that rather than marketing strategy being a controlled and stabilising force for firms in their relationships with customers, it can often lead to socially produced spaces where consumers and, importantly, other multiple actors form a social movement to actively attempt to destabilise it and contest its legitimacy. Using an innovative research approach, the findings of this study show how social movements proactively enrol and mobilise a wide range of relevant actors into a network of influence. Critical to this are rhetorical strategies, acting as important levers in attempts to destabilise and delegitimise a dominant firm's marketing strategy.

Strong Coupling and Long-Range Collective Interactions in Optomechanical Arrays

We investigate the collective optomechanics of an ensemble of scatterers inside a Fabry-Pérot resonator and identify an optimized configuration where the ensemble is transmissive, in contrast to the usual reflective optomechanics approach. In this configuration, the optomechanical coupling of a specific collective mechanical mode can be several orders of magnitude larger than the single-element case, and long-range interactions can be generated between the different elements since light permeates throughout the array. This new regime should realistically allow for achieving strong single-photon optomechanical coupling with massive resonators, realizing hybrid quantum interfaces, and exploiting collective long-range interactions in arrays of atoms or mechanical oscillators.

'Sometimes I wish I was an "ex" ex-prisoner': identity processes in the collective action participation of former prisoners in Northern Ireland

Since the signing of the Northern Ireland peace agreement a plethora of community based prisoner self-help organisations have been established wherein former prisoners staff, manage and deliver services to colleagues. By forging and maintaining their collective identities through community based mutual aid, members of these self-help organisations have progressed to create not only individual change/assistance but have also developed and evolved to tackle serious wider social issues which impact on the members of their organisations. This article critically analyses how the conditions of a post conflict society can influence both the development and evolution of these organisations and also how members situate their claims about the self in the organisation and beyond. Using the social movement framework it is argued that the work of these self-help organisations have given rise to a new politics of identity … that is the ‘politically motivated’ ex-prisoner. ©2013 Taylor & Francis

Fragility of the spin-glass-like collective state to a magnetic field in an interacting Fe-C nanoparticle system

The effect of applied magnetic fields on the collective nonequilibrium dynamics of a strongly interacting Fe-C nanoparticle system has been investigated. It is experimentally shown that the magnetic aging diminishes to finally disappear for fields of moderate strength. The field needed to remove the observable aging behavior increases with decreasing temperature. The same qualitative behavior is observed in an amorphous metallic spin glass (Fe0.15Ni0.85)(75)P16B6Al3.

Variation and Change in French Morphosyntax: The Case of Collective Nouns

Collective nouns such as majorité or foule have long been of interest to linguists for their unusual semantic properties, and provide a valuable source of new data on the evolution of French grammar. This book tests the hypothesis that plural agreement with collective nouns is becoming more frequent in French. Through an analysis of data from a variety of sources, including sociolinguistic interviews, gap-fill tests and corpora, the complex linguistic and external factors which affect this type of agreement are examined, shedding new light on their interaction in this context. Broader questions concerning the methodological challenges of studying variation and change in morphosyntax, and the application of sociolinguistic generalisations to the French of France, are also addressed.

Reviews:

‘Cet ouvrage constitue un apport majeur dans le champ de la linguistique variationniste et diachronique, tant par les résultats mis au jour que par la qualité de sa démarche méthodologique.’ — Sophie Prévost, French Studies 69.4, October 2015, 578-79

‘While language variation and change have been the focal point for linguists on this side of the Atlantic, Tristram argues that studies on morphosyntactic variation in French studies are lacking due to a focus on phonology and dialectology as well as denial of variation and change in the French language. Tristram’s book is thus a welcome contribution.’ — Samira Hassa, French Review 89.3, 2016, 108

‘Anyone teaching variation in French will want to talk about the findings and reflections reported in this study. A remarkable amount of ground is covered in a small compass. This is a highly welcome addition to the Legenda list, and one must hope that further linguistics titles will be added to it before very long.’ — Nigel Armstrong, Journal of French Language Studies 26.2, 2016, 211-13

Optimizing Research on End-of-Life Care for Seniors:The Collective New Emerging Team on End of Life Care for Seniors University of Ottawa, Institute of Palliative Care

Background: End-of-life care for seniors is an important and neglected area of research. The University of Ottawa Institute of Palliative Care has expanded its research capacity by developing a Canadian Institutes of Health Research (CIHR) funded new emerging team on end-of-life care for seniors. This initiative brings together an interdisciplinary team of researchers from palliative care and geriatrics to develop a comprehensive program of research. Methods: 1) A variety of investigators from the fields of palliative care and geriatrics and disciplines of epidemiology, medicine, nursing, psychology and social work will collaborate on the development of a research agenda focussed on end-of-life care for seniors. 2) The conceptual model for the research program consists of 4 broad interrelated domains that are congruent with the CIHR themes of health services, clinical issues, population health and psychosocial, cultural, spiritual and ethical issues; this framework will guide the research program and all studies emanating from the program. 3) Research studies will focus on 5 areas of inquiry that are central to end-of-life care for seniors: palliative end-of-life care for rural seniors, care settings, burden, role of volunteers, and delirium. Results: This new team has the potential to obtain peer-reviewed funding, recruit and train a new generation of researchers, and build a network of concerned researchers. Conclusions: The new team should ultimately contribute to an improved quality of care for seniors who are approaching death.

Community identity as resource and context: A mixed method investigation of coping and collective action in a disadvantaged community

Community identities enhance well-being through the provision of social support and feelings of collective efficacy as well as by acting as a basis for collective action and social change. However, the precise mechanisms through which community identity acts to enhance well-being are complicated by stigmatisation which potentially undermines solidarity and collective action. The present research examines a real-world stigmatised community group in order to investigate: (1) the community identity factors that act to enhance well-being, and (2) the consequences of community identity for community action. Study 1 consisted of a household survey conducted in disadvantaged areas of Limerick city in Ireland. Participants (n=322) completed measures of community identification, social support, collective efficacy, community action, and psychological well-being. Mediation analysis indicated that perceptions of collective efficacy mediated the relationship between identification and well-being. However, levels of self-reported community action were low and unrelated to community identification. In Study 2, twelve follow–up multiple-participant interviews with residents and community group workers were thematically analysed, revealing high levels of stigmatisation and opposition to identity-related collective action. These findings suggest the potential for stigma to reduce collective action through undermining solidarity and social support.