Majorana fermions manifested as interface-states in semiconductor hybrid structures

Motivated by recent proposals for the generation of Majorana fermions in semiconducting hybrid structures, we examine possible experimental fingerprints of such excitations. Whereas previous works mainly have focused on zero-energy states in vortex cores in this context, we demonstrate analytically an alternative route to detection of Majorana excitations in semiconducting hybrid structures: interface-bound states that may be probed directly via conductance spectroscopy or STM-measurements. We estimate the necessary experimental parameters required for observation of our predictions.Comment: 4 pages, 2 figures

How can non-elected representatives secure democratic representation?

Research on the democratic legitimacy of non-elected actors influencing policy while acting as representatives is often lacking in governance literature, despite being increasingly relevant worldwide. Recent theories of representation argue that there are non-electoral mechanisms to appoint such non-elected representatives and hold them responsible for their actions. Consequently, democratic non-electoral representation can be achieved. Through empirical analysis, this article explores democratic non-electoral representation in governance networks by comparing how non-elected representatives, their constituents and the decision-making audience understand the outcome of representation to benefit the constituency, authorisation and accountability. The research findings conclude that all three groups mostly share the understanding of democratic non-electoral representation as ongoing interactions between representatives and constituents, multiple (if any) organisational and discursive sources of authorisation and deliberative aspects of accountability. All of these are non-electoral mechanisms that secure democratic representation. These findings make an important contribution to the literature on non-electoral representation in policymaking.publishedVersio

Encounters with Alex

In the 80th anniversary book for Alex M\"uller I wrote a story of our scientific collaboration, Shared Fascinations. This time I will be more personal, about the human side of our collaboration and encounters, while also referring to episodes mentioned in Shared Fascinations.Comment: 9 pages, 5 figure

To kalon and the experience of art

Under embargo until: 2021-09-18In the Republic, Plato seems to advocate the banning of most extant poetry, because of its corrupting effect on the soul. A central claim in the next section will be that thumos as a specific module or capacity of the soul, as this is depicted in the Republic, is supposed to be trained to respond to what is kalon. The very notion of truth seems at times to be considered primarily in terms of impact with regard to the kalon. It is in this sense that “telling the greatest falsehood about the most important things make a fine story. Aristotle takes the artist’s activity and product to be kalon in being ideally suited to create a special form of cognitive experience in the spectator or reader. To very briefly recapitulate the philosophers’ paradigmatic art recipients, Plato’s audience is a mass of people, some of them very young, corrupted on a psychological level below the threshold of rational, even conscious processing.acceptedVersio

The consequences of institutional design on collaborative arrangements’ power to influence urban freight policymaking

Karin Fossheim, Jardar Andersen, The consequences of institutional design on collaborative arrangements’ power to influence urban freight policymaking, Case Studies on Transport Policy, Volume 10, Issue 2, 2022, Pages 1325-1331, ISSN 2213-624X, https://doi.org/10.1016/j.cstp.2022.04.017 (https://www.sciencedirect.com/science/article/pii/S2213624X2200092X)Collaborative governance is becoming increasingly important as a mode of urban freight policymaking. Bringing together actors from private and public sectors in forums makes it possible to move beyond general discussions of delivery challenges to the innovation of joint solutions and lasting improvements to the freight transport system. For such cross-sector collaborations to function, participants must experience a sense of power to influence policy. The institutional design, i.e., the inclusiveness of the collaboration and the interdependence between the participants, may condition this possibility. Consequently, this article investigates how the institutional design of collaborative arrangements associated with urban freight affects participants’ perceptions of power to influence policymaking. We interviewed 37 participants in three different collaborations in Oslo, Norway. The results indicate that institutional design affects participants’ perceptions of power to influence policymaking. Inclusive collaborations, in which participants are not interdependent, provide participants with the most power to influence policy, rather than exclusive collaborations, in which participants are highly interdependent.The consequences of institutional design on collaborative arrangements’ power to influence urban freight policymakingpublishedVersio

Phase transitions in a three dimensional U(1)×U(1)U(1) \times U(1) lattice London superconductor

We consider a three-dimensional lattice $U(1) \times U(1)$ superconductor in the London limit, with two individually conserved condensates. The problem, generically, has two types of intercomponent interactions of different characters. First, the condensates are interacting via a minimal coupling to the same fluctuating gauge field. A second type of coupling is the direct dissipationless drag represented by a local intercomponent current-current coupling term in the free energy functional. The interplay between these two types of interactions produces a number of physical effects not present in previously investigated $U(1)\times U(1)$ models with only one kind of intercomponent interaction. In this work, we present a study of the phase diagram of a $U(1) \times U(1)$ superconductor which includes both of these interactions. We study phase transitions and two types of competing paired phases which occur in this general model: (i) a metallic superfluid phase (where there is order only in the gauge invariant phase difference of the order parameters), (ii) a composite superconducting phase where there is order in the phase sum of the order parameters which has many properties of a single-component superconductor but with a doubled value of electric charge. We investigate the phase diagram with particular focus on what we call "preemptive phase transitions". These are phase transitions {\it unique to multicomponent condensates with competing topological objects}. A sudden proliferation of one kind of topological defects may come about due to a fluctuating background of topological defects in other sectors of the theory.Comment: 17 pages, 6 figures. Submitted to Physical Review

Tunneling conductance in ss- and d-wave superconductor-graphene junctions: Extended Blonder-Tinkham-Klapwijk formalism

We investigate the conductance spectra of a normal/superconductor graphene junction using the extended Blonder-Tinkham-Klapwijk formalism, considering pairing potentials that are both conventional (isotropic s-wave) and unconventional (anisotropic d-wave). In particular, we study the full crossover from normal to specular Andreev reflection without restricting ourselves to special limits and approximations, thus expanding results obtained in previous work. In addition, we investigate in detail how the conductance spectra are affected if it is possible to induce an unconventional pairing symmetry in graphene, for instance a d-wave order parameter. We also discuss the recently reported conductance-oscillations that take place in normal/superconductor graphene junctions, providing both analytical and numerical results.Comment: 14 pages, 16 figures. High-resolution figures available in the published versio

Costume matter. Exploring microorganisms, fungi and berries as biobased material in contemporary costume design.

Costume materiality has emerged as a current focus in costume theory and practice, as is the significance of costume material and costume as material with agency. Biobased material development is a rapidly evolving research landscape in a variety of fields, as well as a timely topic given the current global considerations of the impact of human activity on the environment. Material knowledge is a fundamental part of a costume designer´s practice, yet how biobased materials can be explored and understood as medium for subjective creative expression through contemporary costume design is currently understudied. This thesis is a personal exploration and reflection on working with selected species of fungi, algae, berries and microbes as medium in costume design. This thesis aims to present biobased materials as viable material alternatives in contemporary costume design, and to explore how selected such materials may be assimilated into the complex processes of costume design and collaborative performance making. This thesis consists of an artistic exploration with biobased materials in the context of costume design, through three specific contemporary dance productions, and a written study reflecting on this practice. The artistic component is located within my own work as costume designer on the dance production a life - nomadic melodrama (2017), which, together with the productions Posthuman (2016) and Posthuman days (2018) inform the thesis. These three contemporary dance works are connected through using specific new materialist philosophy as theoretical starting points for the collective performance making process, and through my approach as costume designer exploring a biobased costume materiality as a conceptual response to this theory. I apply a multi-method research approach to this practice-based thesis In this written reflection and analysis of the works I attempt to trace a narrative of my personal artistic process of engaging with biobased materials in relation to costume design, and how this material approach has affected my understanding of costume materiality in the context of live contemporary dance performance. My costume material approach is a continuous enquiry that develops from one production to the next one, and in this written thesis I trace, analyse and reflect on this process. This thesis suggests that biobased materials can not only be viable as material alternatives in costume practices, but also have the potential to generate interesting aesthetic and performative qualities to the materiality of a live performance when embedded into the shared process of performance making