Numerically exact full counting statistics of the energy current in the Kondo regime

We use the inchworm Quantum Monte Carlo method to investigate the full counting statistics of particle and energy currents in a strongly correlated quantum dot. Our method is used to extract the heat fluctuations and entropy production of a quantum thermoelectric device, as well as cumulants of the particle and energy currents. The energy--particle current cross correlations reveal information on the preparation of the system and the interplay of thermal and electric currents. We furthermore demonstrate the signature of a crossover from Coulomb blockade to Kondo physics in the energy current fluctuations, and show how the conventional master equation approach to full counting statistics systematically fails to capture this crossover

Calculation of the current response in a nanojunction for an arbitrary time-dependent bias: application to the molecular wire

Recently [Phys. Rev. B 91, 125433 (2015)] we derived a general formula for the time-dependent quantum electron current through a molecular junction subject to an arbitrary time-dependent bias within the Wide Band Limit Approximation (WBLA) and assuming a single particle Hamiltonian. Here we present an efficient numerical scheme for calculating the current and particle number. Using the Pad\'e expansion of the Fermi function, it is shown that all frequency integrals occurring in the general formula for the current can be removed analytically. Furthermore, when the bias in the reservoirs is assumed to be sinusoidal it is possible to manipulate the general formula into a form containing only summations over special functions. To illustrate the method, we consider electron transport through a one-dimensional molecular wire coupled to two leads subject to out-of-phase biases. We also investigate finite size effects in the current response and particle number that results from the switch-on of such a bias

Social enterprise as a socially rational business

Purpose: This paper examines the discourses that influence policy and practice in social enterprises. In institutional circles, arguments are shaped by the desire to protect assets for the community, while entrepreneurial discourses favour a mixture of investment sources, surplus sharing and inclusive systems of governance. A critique is outlined that challenges policy-makers and academics to move beyond the heated debate on ‘business-like’ activity through a deeper understanding of the social relations entered into (and created by) different social entrepreneurial activities. Design/Methodology/Approach: The paper is wholly theoretical. Firstly, contradictions are exposed through a review of practitioner and scholarly literature. Thereafter, empirically grounded studies are used to develop a theoretical model that accommodates and accounts for diverse practices. A broader perspective, that views human behaviour as a product of, and support system for, our socio-sexual choices, is deployed to extend understanding of social capital. By integrating this into governance theory, workplaces come to be seen as complex centres of community building replete with economic and social goals. The concept of ‘social rationality’ is elaborated as an alternative way to understand the legitimacy of social entrepreneurial activity and management practice. Originality/Value: The paper concludes by developing a framework and typology that theorises social enterprise as a heterogeneous business movement. Each form of social enterprise integrates socially rational thinking into its policies and practices. This suggests a different educational agenda for social entrepreneurs oriented towards the equitable distribution, and not accumulation, of social and economic capital. Keywords: Social Enterprise, Governance, Social Rationality, Social Capital, Co-operative Practice Paper Type: Conceptual pape