A Dynamic Analysis of Licensing: The Boomerang Effect and Grant-Back Clauses

This paper develops an incomplete contract model of the licensing relationship to analyze the dynamic effects of licensing on R&D competition in the innovation market and to examine the rationale for often observed grant-back clauses. Of particular concern are how the consideration of future competition distorts the licensing relationship and how the "grant-back" clause can mitigate this distortion. I also evaluate the validity of the casual antitrust argument that grant-back clauses may adversely affect competition because they reduce the licensee's incentive to engage in R&D and thereby limit rivalry in innovation markets.

Magnetic phases of orbital bipartite optical lattices

In the Hamburg cold atom experiment with orbital states in an optical lattice, $s$- and $p$-orbital atomic states hybridize between neighbouring sites. In this work we show how this alternation of sites hosting $s$- and $p$-orbital states gives rise to a plethora of different magnetic phases, quantum and classical. We focus on phases whose properties derive from frustration originating from a competition between nearest and next nearest neighbouring exchange interactions. The physics of the Mott insulating phase with unit filling is described by an effective spin-1/2 Hamiltonian showing great similarities with the $J_1$-$J_2$ model. Based on the knowledge of the $J_1$-$J_2$ model, together with numerical simulations, we discuss the possibility of realising a quantum spin liquid phase in the present optical lattice system. In the superfluid regime we consider the parameter regime where the $s$-orbital states can be adiabatically eliminated to give an effective model for the $p$-orbital atoms. At the mean-field level we derive a generalized classical $XY$ model, and show that it may support maximum frustration. When quantum fluctuations can be disregarded, the ground state is expected to be a spin glass. Even with quantum fluctuations present it has been debated whether a spin liquid may persist at the point of full frustration.Comment: 27 page

Patent Pools and Cross-Licensing in the Shadow of Patent Litigation

This paper develops a framework to analyze the incentives to form a patent pool or engage in cross-licensing arrangements in the presence of uncertainty about the validity and coverage of patents that makes disputes inevitable. It analyzes the private incentives to litigate and compares them with the social incentives. It shows that pooling arrangements can have the effect of sheltering invalid patents from challenges. This result has an antitrust implication that patent pools should not be permitted until after patentees have challenged the validity of each other’s patents if litigation costs are not too large.

Tying in Two-Sided Markets with Multi-Homing

This paper analyzes the effects of tying arrangements on market competition and social welfare in two-sided markets when economic agents can engage in multi-homing; that is, they can participate in multiple platforms in order to reap maximal network benefits. The model shows that tying induces more consumers to multi-home and makes platform-specific exclusive contents available to more consumers, which is also beneficial to content providers. As a result, tying can be welfare-enhancing if multi-homing is allowed, even in cases where its welfare impacts are negative in the absence of multi-homing. The analysis thus can have important implications for recent antitrust cases in industries where multi-homing is prevalent.tying, two-sided markets, (indirect) network effects, multi-homing

Glueball-Induced Partonic Energy Loss in Quark-Gluon Plasma

We discuss the energy loss of energetic parton jets in quark-gluon plasma above the deconfinement temperature $T_c$ by the interaction with scalar and pseudoscalar glueballs. It is shown that the loss by this mechanism is quite important and may play the important role of the observed jet-quenching.Comment: 5 pages, 3 figures, version to appear in Phys.Rev.