672 research outputs found

    On the ubiquity of Beutler-Fano profiles: from scattering to dissipative processes

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    Fano models - consisting of a Hamiltonian with discrete-continuous spectrum - are one of the basic toy models in spectroscopy. They have been succesfull in explaining the lineshape of experiments in atomic physics and condensed matter. These models however have largely been out of the scope of dissipative dynamics, with ony a handful of works considering the effect of a thermal bath. Yet in nanostructures and condensed matter systems, dissipation strongly modulates the dynamics. In this article, we present an overview of the theoretical works dealing with Fano interferences coupled to a thermal bath and compare them to the scattering formalism. We provide the solution to any discrete-continuous Hamiltonian structure within the wideband approximation coupled to a Markovian bath. In doing so, we update the toy models that have been available for unitary evolution since the 1960s. We find that the Fano lineshape is preserved as long as we allow a rescaling of the parameters, and an additional Lorentzian contribution that reflects the destruction of the interference by dephasings. We discuss the pertinence of each approach - dissipative and unitary - to different experimental setups: scattering, transport and spectroscopy of dissipative systems. We finish by discussing the current limitations of the theories due to the wideband approximation and the memory effects of the bath.Comment: Expanded bibliography, minor typos correcte

    Introducing conflict as the microfoundation of organizational ambidexterity

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    This article contributes to our understanding of organizational ambidexterity by introducing conflict as its microfoundation. Existing research distinguishes between three approaches to how organizations can be ambidextrous, that is, engage in both exploitation and exploration. They may sequentially shift the strategic focus of the organization over time, they may establish structural arrangements enabling the simultaneous pursuit of being both exploitative and explorative, or they may provide a supportive organizational context for ambidextrous behavior. However, we know little about how exactly ambidexterity is accomplished and managed. We argue that ambidexterity is a dynamic and conflict-laden phenomenon, and we locate conflict at the level of individuals, units, and organizations. We develop the argument that conflicts in social interaction serve as the microfoundation to organizing ambidexterity, but that their function and type vary across the different approaches toward ambidexterity. The perspective developed in this article opens up promising research avenues to examine how organizations purposefully manage ambidexterity

    Bell-type inequalities for cold heteronuclear molecules

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    We introduce Bell-type inequalities allowing for non-locality and entanglement tests with two cold heteronuclear molecules. The proposed inequalities are based on correlations between each molecule spatial orientation, an observable which can be experimentally measured with present day technology. Orientation measurements are performed on each subsystem at diferent times. These times play the role of the polarizer angles in Bell tests realized with photons. We discuss the experimental implementations of the proposed tests, which could also be adapted to other high dimensional quantum angular momenta systems.Comment: 4 page

    Fano-Liouville Spectral Signatures in Open Quantum Systems

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    The scattering amplitude from a set of discrete states coupled to a continuum became known as the Fano profile, characteristic for its asymmetric lineshape and originally investigated in the context of photoionization. The generality of the model, and the proliferation of engineered nanostructures with confined states gives immense success to the Fano lineshape, which is invoked whenever an asymmetric lineshape is encountered. However, many of these systems do not conform to the initial model worked out by Fano in that i) they are subject to dissipative processes and ii) the observables are not entirely analogous to the ones measured in the original photoionization experiments. In this letter, we work out the full optical response of a Fano model with dissipation. We find that the exact result for absorption, Raman, Rayleigh and fluorescence emission is a modified Fano profile where the typical lineshape has an additional Lorentzian contribution. Expressions to extract model parameters from a set of relevant observables are given.Comment: corrected typo
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