Lasing in circuit quantum electrodynamics with strong noise

We study a model which can describe a superconducting single electron transistor (SSET) or a double quantum dot coupled to transmission-line oscillator. In both cases the degree of freedom is given by a charged particle, which couples strongly to the electromagnetic environment or phonons. We consider the case where a lasing condition is established and study the dependence of the average photon number in the resonator on the spectral function of the electromagnetic environment. We focus on three important cases: a strongly coupled environment with a small cut-off frequency, a structured environment peaked at a specific frequency and 1/f-noise. We find that the electromagnetic environment can have a substantial impact on the photon creation. Resonance peaks are in general broadened and additional resonances can appear

Irreversibility on the Level of Single-Electron Tunneling

We present a low-temperature experimental test of the fluctuation theorem for electron transport through a double quantum dot. The rare entropy-consuming system trajectories are detected in the form of single charges flowing against the source-drain bias by using time-resolved charge detection with a quantum point contact. We find that these trajectories appear with a frequency that agrees with the theoretical predictions even under strong nonequilibrium conditions, when the finite bandwidth of the charge detection is taken into account

Statistics of voltage fluctuations in resistively shunted Josephson junctions

The intrinsic nonlinearity of Josephson junctions converts Gaussian current noise in the input into non-Gaussian voltage noise in the output. For a resistively shunted Josephson junction with white input noise we determine numerically exactly the properties of the few lowest cumulants of the voltage fluctuations, and we derive analytical expressions for these cumulants in several important limits. The statistics of the voltage fluctuations is found to be Gaussian at bias currents well above the Josephson critical current, but Poissonian at currents below the critical value. In the transition region close to the critical current the higher-order cumulants oscillate and the voltage noise is strongly non-Gaussian. For coloured input noise we determine the third cumulant of the voltage.Comment: 9 pages, 5 figure

An integrative approach to conceptualizing sustainable resilience

Vulnerability, resilience, and sustainability are three concepts commonly used in assessing the quality of a variety of systems. While each can be applied independently when performing risk analysis, there is growing interest across multiple disciplines in understanding how these concepts can be integrated when considering complex adaptive systems, such as communities. In this paper, we identify issues related to the use of these respective concepts in assessing complex adaptive systems, and describe how these issues may produce imbalanced results and maladaptive outcomes. We identify five critical areas where alignment and integration across concepts can lead to improved system assessment. As a result, we introduce a new paradigm, sustainable resilience, in which these concepts are integrated to enable alignment of adaptation and transformation strategies with desired resilience outcomes. This work provides the foundation for the development of an integrated assessment framework to help guide informed risk-based decisionmaking for sustainable and resilient systems