Monopolistic Intermediation in the Gehrig (1993) Search Model Revisited

We modify the basic Gehrig (1993) model. In this model, individual agents are either buyers or sellers. They can choose between joining the search market, joining the monopolistic intermediary or remaining inactive. In the search market, agents are randomly matched and the price at which exchange takes place is set bilaterally. If agents join the intermediary, buyers have to pay an ask price set in advance by the intermediary. Likewise, if sellers decide to deal through the intermediary, they get the bid price set by the intermediary. As Gehrig shows, this model has an equilibrium in which the search market and the market of the monopolistic intermediary are simultaneously open. The intermediary makes positive profits because he trades at a positive ask-bid spread, and the set of individual agents is tripartite: High valuation buyers and low cost sellers deal through the intermediary, buyers and sellers with average valuations and average costs are active in the search market, and low valuation buyers and high cost sellers remain inactive. We modify this basic model by imposing a sequential structure. We assume that the monopolistic intermediary first has to buy the good from sellers on the input market before he can sell it to buyers on the output market. As a consequence of the sequential structure, the subgame following capacity setting has a unique subgame perfect equilibrium with an active search market. On the equilibrium path, the equilibrium analyzed by Gehrig is replicated.market-making; market microstructure; competing exchange mechanisms

Information and Barometric Prices: An Explanation for Price Stickiness

Price stickiness plays a decisive role in many macroeconomic models, yet why prices are sticky remains a puzzle. We develop a microeconomic model in which two competing firms are free to set prices, but face uncertainty about the state of demand. With some probability, there is a positive demand shock, which is observed but by one firm. In equilibrium, only the informed firm adjusts its price after the shock, while the uninformed firm raises its price only with a delay, after observing the price of its competitor. Hence, prices are sticky in the sense that one firm's price does not adjust immediately. Further, if getting information is costly, the model implies that the larger firm tends to be better informed and to adjust its price first.Price Setting; Sticky Prices; Asymmetric Information; Barometic Price Leadership

On Cheating and Whistle-Blowing

We study the role of whistle-blowing in the following inspection game. Two agents who compete for a valuable prize can either behave legally or illegally. After the competition, a controller investigates the agents' behavior. This control game has a unique equilibrium in mixed strategies. We then add a whistle-blowing stage, where the controller asks the loser to blow the whistle. This extended game has a unique perfect Bayesian equilibrium in which only a cheating loser accuses the winner of cheating and the controller tests the winner if and only if the winner is accused of cheating. Whistle-blowing reduces the frequencies of cheating, is less costly in terms of test frequencies, and leads to a strict Pareto-improvement if punishments for cheating are sufficiently large.Principal-two-Agents; Inspection Games; Asymmetric Information; Signalling

Molecular Electronics – Resonant Transport through Single Molecules

The mechanically controllable break-junction technique (MCBJ) enables us to investigate charge transport through an individually contacted and addressed molecule in ultra-high vacuum (UHV) environment at variable temperature ranging from room temperature down to 4 K. Using a statistical measurement and analysis approach, we acquire current–voltage (I-V) characteristics during the repeated formation, manipulation, and breaking of a molecular junction. At low temperatures, voltages accessing the first molecular orbitals in resonance can be applied, providing spectroscopic information about the junction's energy landscape, in particular about the molecular level alignment in respect to the Fermi energy of the electrodes. Thereby, we can investigate the non-linear transport properties of various types of functional molecules and explore their potential use as functional building blocks for future nano-electronics. An example will be given by the reversible and controllable switching between two distinct conductive states of a single molecule. As a proof-of-principle for functional molecular devices, a single-molecule memory element will be demonstrated

An action plan for a suitable customer loyalty programme for Matterhorn Valley Hotels

Today, a customer loyalty programmes is considered a common marketing tool in tourism. It is said that loyalty programmes increase the revenue of a well-handled business, others doubt the effectiveness. Matterhorn Valley Hotels’ loyalty programme is experiencing issues and therefore, a new loyalty programme is necessary

Functional Nanopores: A Solid-state Concept for Artificial Reaction Compartments and Molecular Factories

On the road towards the long-term goal of the NCCR Molecular Systems Engineering to create artificial molecular factories, we aim at introducing a compartmentalization strategy based on solid-state silicon technology targeting zeptoliter reaction volumes and simultaneous electrical contact to ensembles of well-oriented molecules. This approach allows the probing of molecular building blocks under a controlled environment prior to their use in a complex molecular factory. Furthermore, these ultra-sensitive electrical conductance measurements allow molecular responses to a variety of external triggers to be used as sensing and feedback mechanisms. So far, we demonstrate the proof-of-concept by electrically contacting self-assembled mono-layers of alkane-dithiols as an established test system. Here, the molecular films are laterally constrained by a circular dielectric confinement, forming a so-called `nanopore`. Device yields above 85% are consistently achieved down to sub-50 nm nanopore diameters. This generic platform will be extended to create distributed, cascaded reactors with individually addressable reaction sites, including interconnecting micro-fluidic channels for electrochemical communication among nanopores and sensing sites for reaction control and feedback. In this scientific outlook, we will sketch how such a solid-state nanopore concept can be used to study various aspects of molecular compounds tailored for operation in a molecular factory

Molecular switch controlled by pulsed bias voltages

It was observed in recent experiments that the current-voltage characteristics (IV) of BPDN-DT (bipyridyl- dinitro- oligophenylene- ethynylene- dithiol) can be switched in a very controlled manner between "on" and "off" traces by applying a pulse in a bias voltage, V_bias. We have calculated the polaron formation energies to check a frequently held belief, namely, that the polaron formation can explain the observed bistability. Our results are not consistent with such a mechanism. Instead, we propose a conformational reorientation. The molecule carries an intrinsic dipole moment which couples to V_bias. Ramping V_bias exerts a force on the dipole that can reorient ("rotate") the molecule from the ground state ("off") into a metastable configuration ("on") and back. By elaborated electronic structure calculations, we identify a specific path for this rotation through the molecule's conformational phase space. We show that this path has sufficiently high barriers to inhibit thermal instability but still the molecule can be switched in the voltage range of the junction stability. The theoretical IVs reproduce qualitatively the key experimental observations. We propose, how the alternative mechanism of conductance switching can be experimentally verified.Comment: LaTEX, 6 Figures, published versio

Scalable, Nanometer-Accurate Fabrication of All-Dielectric Metasurfaces with Narrow Resonances Tunable from Near Infrared to Visible Wavelengths

Dielectric metasurfaces are a class of flat-optical elements that provide new ways to manipulate light. Irrespective of the underlying operation principle, the realization of such nanometer-sized structures requires a high fabrication accuracy, e.g., to match resonant conditions. While electron-beam lithography (EBL) achieves feature sizes below 10 nm, transparent substrates, as used for transmission devices, are challenging due to proximity effects. Furthermore, EBL's sequential exposure limits the exposable area, making it unaffordable for applications. Here, a novel fabrication route is described based on a master template created by EBL, which is then replicated by nanoimprint lithography (NIL). A three-layer process enables high-resolution nanoimprint resists with low etching selectivity with respect to semiconductors yet to be used. The resulting structures are highly reproducible and defect-free thanks to the selective removal of residual layers and a master not suffering from proximity effects. Exemplarily, elliptical Mie resonators are fabricated with tunable resonances from the near infrared (NIR) to the visible wavelength regime. They reveal a high uniformity and sensitivity toward dielectric changes. The generic fabrication approach enables upscaling of nanoscale metasurfaces to wafer scales by step-and-repeat techniques and deployment of the optical devices fabricated in real-world applications due to massively reduced costs