In the unique bid auction, the bidder with the lowest unmatched bid wins.

By Simone Pigolotti, Sebastian Bernhardsson, Jeppe Juul, Gorm Galster, and Pierpaolo Vivo

In lowest unique bid auctions, N players bid for an item. The winner is whoever places the lowest bid, provided that it is also unique. We derive an analytical expression for the equilibrium distribution of the game as a function of N and study its properties, which are then compared with a large dataset of internet auctions. The empirical collective strategy reproduces the theoretical equilibrium with striking accuracy for small N, while for larger N the quality of the fit deteriorates. As a consequence, the same game exhibits lottery-like and game-of-skill features, depending on the collective size of the bidding pool. Our results question the actual possibility of a large population to adapt and find the optimal strategy when participating in a collective game.

The article can be found here.

In the multiple disease model, disease clusters spread in fractal shapes.

By Jeppe Juul and Kim Sneppen

Diseases emerge, persist and vanish in an ongoing battle for available hosts. Hosts, on the other hand, defend themselves by developing immunity that limits the ability of pathogens to reinfect them. We here explore a multi-disease system with emphasis on mutual exclusion. We demonstrate that such a system develops towards a steady state, where the spread of individual diseases self-organizes to a state close to that of critical percolation, without any global control mechanism or separation of time scale. For a broad range of introduction rates of new diseases, the likelihood of transmitting diseases remains approximately constant.

The article can be found here.

Cross section of the superconducting cable used.

By Jeppe Juul, Esben Mølgaard, Jens Jensen, Niels Hessel Andersen, Asger Bech Abrahamsen, Dag Willen, Chresten Træholt, Carsten Thidemann, Heidi Lentge

The AC losses in superconducting multifilament BiSCCO-2223 tapes and a 3.15 m single phase test cable were measured at 77 K using an electrical transport method. The cable had an inner diameter of 42 mm, it was composed of a single layer of 31 multifilament tapes and had a critical current of Ic=4.1 kA. The measured losses of the tapes were found to be in good agreement with the Norris ellipse model. The losses of the cable were, for high currents, found to be bounded by the monoblock and independent Norris ellipse models.

You can find the article online here or download it here