Partition theory: A very simple illustration

We illustrate the main features of a recently proposed method based on ensemble density functional theory to divide rigorously a complex molecular system into its parts [M.H. Cohen and A. Wasserman, J. Phys. Chem. A 111, 2229 (2007)]. The illustrative system is an analog of the hydrogen molecule for which analytic expressions for the densities of the parts (hydrogen "atoms") are found along with the "reactivity potential" that enters the theory. While previous formulations of Chemical Reactivity Theory lead to zero, or undefined, values for the chemical hardness of the isolated parts, we demonstrate they can acquire a finite and positive hardness within the present formulation.Comment: 8 pages, 8 figure

The performativity of sustainability: Assessing the continuity of artisanal fishing livelihoods in Galápagos' precarious waters

This work is about how people develop strategies to make sense of and to deal with the challenges of situating themselves within the global push for 'sustainability.' Sustainability is a concept that I understand to be imagined, socially constructed, remade and ritualized as global actors tote the 'sustainable development' discourse globally and impose it upon local actors' practices. Such foisting typically promises to resolve socio-ecological problems by providing communities with certainties and stabilities such as redeeming issues linked to threatened eco-systems and local actors' precarious livelihoods therein. However, I argue that 'sustainability' indeed fails to fulfil its ideological aspirations. In this light, I take the stance that sustainability is performative, and therefore, enacted through sets of relationships which require critical interrogation. I use the example of artisanal fishermen in the Galápagos Islands to demonstrate how: (i) they deal with local managing authorities and the enterprise of sustainability that disturb their daily lives on land and at sea; (ii) they situate themselves within co-management processes; and (iii) their performativities allow them to make sense of and to deal with their precarious livelihoods by remaking, challenging, and subverting 'sustainability' in effort to remain relevant in Galápagos' evolving eco-political landscape. This occurs, I argue, as fishermen enact performativities that are situated in their material practices, collective, and authoritative. Notions of performativity thus contribute to conceptual understandings of how global actors' ambitions to remake local actors' practices 'sustainably' produces and distributes precarity – and therefore exposes how the latter deal with the precarity resulting from their attempts to remain relevant in Galápagos' eco-political landscape over time

Meditation Matters: Replies to the Anti-McMindfulness Bandwagon!

A critical reply to the anti-mindfulness critics in the collection, who oppose the popular secularized adoption of mindfulness on various grounds (it is not Buddhism, it is Buddhism, it is a tool of neo-capitalist exploitation, etc.), I argue that mindfulness is a quality of consciousness, opposite mindlessness, that may be cultivated through practice, and is almost always beneficial to those who cultivate it

Post-National Foundation of Judith Butler’s and Rossi Braidotti’s Relational Subjectivity

This article draws on examples of Indigenous conceptualizations of nationhood to question the post-national foundation of Judith Butler’s and Rossi Braidotti’s theories of affective subjectivity. The article concludes that the responsibility to respect certain political boundaries is necessary in fostering non-oppressive affective relations. RésuméCet article s’appuie sur des exemples de conceptualisations autochtones de la notion de nation pour remettre en question le fondement post-national des théories de la subjectivité affective de Judith Butler et Rossi Braidotti. L’article conclut que la responsabilité de respecter certaines limites politiques est nécessaire pour favoriser des relations affectives non oppressives

Continuum states from time-dependent density functional theory

Linear response time-dependent density functional theory is used to study low-lying electronic continuum states of targets that can bind an extra electron. Exact formulas to extract scattering amplitudes from the susceptibility are derived in one dimension. A single-pole approximation for scattering phase shifts in three dimensions is shown to be more accurate than static exchange for singlet electron-He$^+$ scattering.Comment: 5 pages, 2 figures, J. Chem. Phys. accepte

Using polymer electrolyte gates to set-and-freeze threshold voltage and local potential in nanowire-based devices and thermoelectrics

We use the strongly temperature-dependent ionic mobility in polymer electrolytes to 'freeze in' specific ionic charge environments around a nanowire using a local wrap-gate geometry. This enables us to set both the threshold voltage for a conventional doped substrate gate and the local disorder potential at temperatures below 200 Kelvin, which we characterize in detail by combining conductance and thermovoltage measurements with modeling. Our results demonstrate that local polymer electrolyte gates are compatible with nanowire thermoelectrics, where they offer the advantage of a very low thermal conductivity, and hold great potential towards setting the optimal operating point for solid-state cooling applications.Comment: Published in Advanced Functional Materials. Includes colour versions of figures and supplementary informatio

Thermoelectric power factor limit of a 1D nanowire

In the past decade, there has been significant interest in the potentially advantageous thermoelectric properties of one-dimensional (1D) nanowires, but it has been challenging to find high thermoelectric power factors based on 1D effect in practice. Here we point out that there is an upper limit to the thermoelectric power factor of non-ballistic 1D nanowires, as a consequence of the recently established quantum bound of thermoelectric power output. We experimentally test this limit in quasi-ballistic InAs nanowires by extracting the maximum power factor of the first 1D subband through I-V characterization, finding that the measured maximum power factors conform to the theoretical limit. The established limit predicts that a competitive power factor, on the order of mW/m-K^2, can be achieved by a single 1D electronic channel in state-of-the-art semiconductor nanowires with small cross-section and high crystal quality

Visualization of usage patterns for web personalization

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Nonlinear thermoelectric response due to energy-dependent transport properties of a quantum dot

Quantum dots are useful model systems for studying quantum thermoelectric behavior because of their highly energy-dependent electron transport properties, which are tunable by electrostatic gating. As a result of this strong energy dependence, the thermoelectric response of quantum dots is expected to be nonlinear with respect to an applied thermal bias. However, until now this effect has been challenging to observe because, first, it is experimentally difficult to apply a sufficiently large thermal bias at the nanoscale and, second, it is difficult to distinguish thermal bias effects from purely temperature-dependent effects due to overall heating of a device. Here we take advantage of a novel thermal biasing technique and demonstrate a nonlinear thermoelectric response in a quantum dot which is defined in a heterostructured semiconductor nanowire. We also show that a theoretical model based on the Master equations fully explains the observed nonlinear thermoelectric response given the energy-dependent transport properties of the quantum dot.Comment: Cite as: A. Svilans, et al., Physica E (2015), http://dx.doi.org/10.1016/j.physe.2015.10.00