Subnanosecond Fluctuations in Low-Barrier Nanomagnets

Fast magnetic fluctuations due to thermal torques have useful technological functionality ranging from cryptography to probabilistic computing. The characteristic time of fluctuations in typical uniaxial anisotropy magnets studied so far is bounded from below by the well-known energy relaxation mechanism. This time scales as $\alpha^{-1}$, where $\alpha$ parameterizes the strength of dissipative processes. Here, we theoretically analyze the fluctuating dynamics in easy-plane and antiferromagnetically coupled nanomagnets. We find in such magnets, the dynamics are strongly influenced by fluctuating intrinsic fields, which give rise to an additional dephasing-type mechanism for washing out correlations. In particular, we establish two time scales for characterizing fluctuations (i) the average time for a nanomagnet to reverse|which for the experimentally relevant regime of low damping is governed primarily by dephasing and becomes independent of $\alpha$, (ii) the time scale for memory loss of a single nanomagnet|which scales as $\alpha^{-1/3}$ and is governed by a combination of energy dissipation and dephasing mechanism. For typical experimentally accessible values of intrinsic fields, the resultant thermal-fluctuation rate is increased by multiple orders of magnitude when compared with the bound set solely by the energy relaxation mechanism in uniaxial magnets. This could lead to higher operating speeds of emerging devices exploiting magnetic fluctuations

Integrating Groupware Activities into Workflow Management Systems

Computer supported cooperative work (CSCW) has been recognized as a crucial enabling technology for multi-user computer-based systems, particularly in cases where synchronous human-human interaction is required between geographically dispersed users. Workflow is an emerging technology that supports complex business processes in modern corporations by allowing to explicitly define the process, and by supporting its execution in a workflow management system (WFMS). Since workflow inherently involves humans carrying out parts of the process, it is only natural to explore how to synergize these two technologies. We analyze the relationships between groupware and workflow management, present our general approach to integrating synchronous groupware tools into a WFMS, and conclude with an example process that was implemented in the Oz WFMS and integrated such tools. Our main contribution lies in the integration and synchronization of individual groupware activities into modeled workflow processes, as opposed to being a built-in part of the workflow WFMS

Critical Behavior of Hadronic Fluctuations and the Effect of Final-State Randomization

The critical behaviors of quark-hadron phase transition are explored by use of the Ising model adapted for hadron production. Various measures involving the fluctuations of the produced hadrons in bins of various sizes are examined with the aim of quantifying the clustering properties that are universal features of all critical phenomena. Some of the measures involve wavelet analysis. Two of the measures are found to exhibit the canonical power-law behavior near the critical temperature. The effect of final-state randomization is studied by requiring the produced particles to take random walks in the transverse plane. It is demonstrated that for the measures considered the dependence on the randomization process is weak. Since temperature is not a directly measurable variable, the average hadronic density of a portion of each event is used as the control variable that is measurable. The event-to-event fluctuations are taken into account in the study of the dependence of the chosen measures on that control variable. Phenomenologically verifiable critical behaviors are found and are proposed for use as a signature of quark-hadron phase transition in relativistic heavy-ion collisions.Comment: 17 pages (Latex) + 24 figures (ps file), submitted to Phys. Rev.

Spatial distribution of Gaussian fluctuations of the molecular field and magnetization in the pyramid-like Ising nanoscopic system interacting with the substrate

We study thermodynamic properties of an Ising model of a ferromagnetic nanoscopic pyramid deposited onto a ferromagnetic bulk substrate. The influence of the interaction between the pyramid and the substrate is calculated in terms of the equilibrium reduced-state (density) operator used for description of thermodynamic properties of nanoscopic systems. The spatial distribution of the fluctuations of molecular field and magnetization in the nanoscopic pyramid is obtained in the Gaussian fluctuations approximation. Experimental consequences for the magnetic force measurements are briefly discussed.Comment: 13 pages, 10 figure

Psychometric Properties of the Norwegian Short Version of the Team Climate Inventory (TCI)

Objective: To examine the psychometric properties of the short version of the Team Climate Inventory (TCI) in a Norwegian sample. Method: A multilevel confirmatory factor analysis (MCFA) was conducted using Mplus. The sample (N = 1380) comprised employees working in the private- (n = 657) and in the public sector (n = 723) in Norway. A multi-group comparison was conducted to examine if the structure of the TCI fits across groups. Results: The fit indices with the original four-factor structure on the within- and between level revealed acceptable results for the total sample (TLI .91, CFI .93, and RMSEA .042). The multi-group analysis did result in significant change to model fit when the factor loadings and intercepts on the between level were fixed across groups, ∆χ2 (25) = 182.58. The individual- and group-level reliability estimates for the total scale of the TCI were satisfying, but not acceptable for two (Participative safety and Support for innovation) of the four scales. Conclusion: The results of the MCFA indicated that the short version of the TCI may be used for assessing team climate for organizations and for research purposes, but some caution should be taken when interpreting results from two sub-scales with marginal reliability

Implementing Activity Structures Process Modeling On Top Of The MARVEL Environment Kernel

Our goal was to implement the activity structures model defined by Software Design & Analysis on top of the MARVEL environment kernel. This involved further design of the activity structures process definition language and enaction model as well as translation and run-time support in terms of facilities provided by MARVEL. The result is an elegant declarative control language for multi-user software processes, with data and activities defined as classes and rules in the previously existing MARVEL Strategy Language. Semantics-based concurrency control is provided by a combination of the MARVEL kernel‘s lock and transaction managers and the send/receive synchronization primitives of the activity structures model

Production of Sodium Bose--Einstein condensates in an optical dimple trap

We report on the realization of a sodium Bose--Einstein condensate (BEC) in a combined red-detuned optical dipole trap, formed by two beams crossing in a horizontal plane and a third, tightly focused dimple trap propagating vertically. We produce a BEC in three main steps: loading of the crossed dipole trap from laser-cooled atoms, an intermediate evaporative cooling stage which results in efficient loading of the auxiliary dimple trap, and a final evaporative cooling stage in the dimple trap. Our protocol is implemented in a compact setup and allows us to reach quantum degeneracy even with relatively modest initial atom numbers and available laser power

Classical Nambu-Goldstone fields

It is shown that a Nambu-Goldstone (NG) field may be coherently produced by a large number of particles in spite of the fact that the NG bosons do not couple to flavor conserving scalar densities like $\bar{\psi}\psi$. If a flavor oscillation process takes place the phases of the pseudo-scalar or flavor violating densities of different particles do not necessarily cancel each other. The NG boson gets a macroscopic source whenever the total (spontaneously broken) quantum number carried by the source particles suffers a net increase or decrease in time. If the lepton numbers are spontaneously broken such classical NG (majoron) fields may significantly change the neutrino oscillation processes in stars pushing the observational capabilities of neutrino-majoron couplings down to $m_{\nu}/300$ GeV.Comment: 11 pages, updated, to appear in PR