The cosmological constant and the relaxed universe

We study the role of the cosmological constant (CC) as a component of dark energy (DE). It is argued that the cosmological term is in general unavoidable and it should not be ignored even when dynamical DE sources are considered. From the theoretical point of view quantum zero-point energy and phase transitions suggest a CC of large magnitude in contrast to its tiny observed value. Simply relieving this disaccord with a counterterm requires extreme fine-tuning which is referred to as the old CC problem. To avoid it, we discuss some recent approaches for neutralising a large CC dynamically without adding a fine-tuned counterterm. This can be realised by an effective DE component which relaxes the cosmic expansion by counteracting the effect of the large CC. Alternatively, a CC filter is constructed by modifying gravity to make it insensitive to vacuum energy.Comment: 6 pages, no figures, based on a talk presented at PASCOS 201

"Silver" product design: Product innovation for older people

Aging populations challenge companies across different countries and industries to respond to the changing needs, demands and expectations of their growing shares of older customers. This opens room for improving or developing innovations - products as well as services - that correspond to the diverse expectations. New product development for older customers or 'Silver' product design is one way to approach the 'silver' market - without explicitly excluding younger customers. Research in this field is still in its infancy. Silver product design focuses on individual autonomy, representing an elementary aspect of good life, disappearing in a more or less continuous manner over the life cycle of a human being. Offering solutions that will allow people to maintain or recover autonomy and to use products and services in an independent manner therefore seems to be a promising avenue for companies innovating across different industries. The general concept of autonomy can be perceived as a boundary-spanning argument and a common denominator for starting development initiatives leading to innovations targeting the silver market. Cross-case analysis based on four different product innovations addressing typical needs of older people are used to present how firms in different industrial contexts and user-settings address such needs, which have their roots in a need to stay autonomous and independent. Technological, marketing and strategy-related observations as well as communalities and differences of the cases are being discussed and very first implications for managing the front end of silver product development sketched. --Demographic change,aging,older users,silver market,innovation management,silver product design,individual autonomy

Microscopic Origin of the 0.7-Anomaly in Quantum Point Contacts

A Quantum point contact (QPC) is a one dimensional constriction, separating two extended electron systems allowing transport between them only though a short and narrow channel. The linear conductance of QPCs is quantized in units of the conductance quantum G_Q=2e^2/h, where e is the electron charge and h is Planck's constant. Thus the conductance shows a staircase when plotted as a function of gate-voltage which defines the width of the channel. In addition measured curves show a shoulder-like step around 0.7G_Q. In this regime QPCs show anomalous behaviour in quantities like electrical or thermal conductance, noise, and thermopower, as a function of external parameters such as temperature, magnetic field, or applied voltage. These phenomena, collectively known as the 0.7-anomaly in QPCs are subject of controversial discussion. This thesis offers a detailed description of QPCs in the parameter regime of the 0.7-anomaly. A model is presented which reproduces the phenomenology of the 0.7-anomaly. We give an intuitive picture and a detailed description of the microscopic mechanism leading to the anomalous behavior. Further, we offer detailed predictions for the behavior of the 0.7-anomaly in the presence of spin-orbit interactions. Our best theoretical results were achieved using an approximation scheme within the functional renormalization group (fRG) which we developed to treat inhomogeneous interacting fermi systems. This scheme, called the coupled ladder approximation (CLA), allows the flow of the two-particle vertex to be incorporated even if the number of interacting sites N, is large, by reducing the number of independent variables which represent the two-particle vertex from O(N^4) to O (N^2)