Dynamics in a Bistable-Element-Network with Delayed Coupling and Local Noise

The dynamics of an ensemble of bistable elements under the influence of noise and with global time-delayed coupling is studied numerically by using a Langevin description and analytically by using 1) a Gaussian approximation and 2) a dichotomous model. We find that for a strong enough positive feedback the system undergoes a phase transition and adopts a non-zero stationary mean field. A variety of coexisting oscillatory mean field states are found for positive and negative couplings. The magnitude of the oscillatory states is maximal for a certain noise temperature, i.e., the system demonstrates the phenomenon of coherence resonance. While away form the transition points the system dynamics is well described by the Gaussian approximation, near the bifurcations it is more adequately described by the dichotomous model.Comment: 2 pages, 2 figures. To be published in the proceedings of "The 3rd International Symposium on Slow Dynamics in Complex Systems", eds. M. Tokuyama, I. Oppenheim, AIP Conf. serie

Judicial Unification in Post-Colonial Indonesia

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AB and Berry phases for a quantum cloud of charge

We investigate the phase accumulated by a charged particle in an extended quantum state as it encircles one or more magnetic fluxons, each carrying half a flux unit. A simple, essentially topological analysis reveals an interplay between the Aharonov-Bohm phase and Berry's phase.Comment: 10 pages, TAUP 2110-93. Te

Quantum Control of Photodissociation via Manipulation of Bond Softening

We present a method to control photodissociation by manipulating the bond softening mechanism occurring in strong shaped laser fields, by varying the chirp sign and magnitude of an ultra-short laser pulse. Manipulation of bond-softening is experimentally demonstrated for strong field (795 nm, 10^12 - 10^13 W/cm^2) photodissociation of H2+, exhibiting substantial increase of dissociation by positively chirped pulses with respect to both negatively chirped and transform limited pulses. The measured kinetic energy release and angular distributions are used to quantify the degree of control of dissociation. The control mechanism is attributed to the interplay of dynamic alignment and chirped light induced potential curves.Comment: 4 pages, 4 figure

Capability in the digital: institutional media management and its dis/contents

This paper explores how social media spaces are occupied, utilized and negotiated by the British Military in relation to the Ministry of Defence’s concerns and conceptualizations of risk. It draws on data from the DUN Project to investigate the content and form of social media about defence through the lens of ‘capability’, a term that captures and describes the meaning behind multiple representations of the military institution. But ‘capability’ is also a term that we hijack and extend here, not only in relation to the dominant presence of ‘capability’ as a representational trope and the extent to which it is revealing of a particular management of social media spaces, but also in relation to what our research reveals for the wider digital media landscape and ‘capable’ digital methods. What emerges from our analysis is the existence of powerful, successful and critically long-standing media and reputation management strategies occurring within the techno-economic online structures where the exercising of ‘control’ over the individual – as opposed to the technology – is highly effective. These findings raise critical questions regarding the extent to which ‘control’ and management of social media – both within and beyond the defence sector – may be determined as much by cultural, social, institutional and political influence and infrastructure as the technological economies. At a key moment in social media analysis, then, when attention is turning to the affordances, criticisms and possibilities of data, our research is a pertinent reminder that we should not forget the active management of content that is being similarly, if not equally, effective

Word-Length Correlations and Memory in Large Texts: A Visibility Network Analysis

We study the correlation properties of word lengths in large texts from 30 ebooks in the English language from the Gutenberg Project (www.gutenberg.org) using the natural visibility graph method (NVG). NVG converts a time series into a graph and then analyzes its graph properties. First, the original sequence of words is transformed into a sequence of values containing the length of each word, and then, it is integrated. Next, we apply the NVG to the integrated word-length series and construct the network. We show that the degree distribution of that network follows a power law, P(k)∼k−γP(k)∼k-γ, with two regimes, which are characterized by the exponents γs≈1.7γs≈1.7 (at short degree scales) and γl≈1.3γl≈1.3 (at large degree scales). This suggests that word lengths are much more strongly correlated at large distances between words than at short distances between words. That finding is also supported by the detrended fluctuation analysis (DFA) and recurrence time distribution. These results provide new information about the universal characteristics of the structure of written texts beyond that given by word frequencies