No abstract

Recently, many digital service providers started to gamify their services to promote continued service usage. Although gamification has drawn attention in both practice and research, it remains unclear how users experience gamified services and how these gameful experiences may increase service usage. This research adopts a user-centered perspective to reveal the underlying gameful experience dimensions during gamified service usage and how they drive continued service usage. Findings from Study 1-a survey with 148 app-users-reveal four essential gameful experience dimensions (skill development, social comparison, social connectedness, and expressive freedom) and how they relate to game mechanics. Study 2, which is based on a survey among 821 app-users, shows that gameful experiences trigger continued service usage through two different types of motivation, namely autonomous and controlled motivation.

No abstract

We employ a functional renormalization group approach to ascertain the pairing mechanism and symmetry in the recently observed superconducting phase of rhombohedral trilayer graphene. Superconductivity in this system occurs in a regime of carrier density and displacement field with a weakly distorted annular Fermi sea. We find that repulsive Coulomb interactions can induce electron pairing on the Fermi surface by taking advantage of momentum-space structure associated with its finite width. The degeneracy between spin-singlet and spin-triplet pairing is lifted by valleyexchange interactions that strengthen under the RG flow and develop nontrivial momentum-space structures. In our calculation, the inner and outer Fermi surfaces prefer d-wave spin-singlet and p-wave spin-triplet pairings, respectively. We predict that a transition from the spin-singlet pairing observed at present to spin-triplet pairing will occur when the electrical gates of the device are positioned further from the dielectric encapsulated trilayer.

We provide a complete theoretical interpretation of the metallic broken spin/valley symmetry states recently discovered in ABC trilayer graphene (ABC) perturbed by a large transverse displacement field. Our conclusions combine insights from ABC trilayer graphene electronic structure models and mean field theory, and are guided by precise magneto-oscillation Fermi-surface-area measurements. We conclude that the physics of ABC trilayer graphene is shaped by the principle of momentum-space condensation, which favors Fermi surface reconstructions enabled by broken spin/valley flavor symmetries when the single-particle bands imply thin annular Fermi seas. We find one large outer Fermi surface enclosed majority-flavor states and one or more small inner hole-like Fermi surfaces enclosed minority-flavor states that are primarily responsible for nematic order. The smaller surfaces can rotate along a ring of van-Hove singularities or reconstruct into multiple Fermi surfaces with little cost in energy. We propose that the latter property is responsible for the quantum oscillation frequency fractionalization seen experimentally in some regions of the carrier-density/displacement-field phase diagram.