Bath-induced decoherence in finite-size Majorana wires at non-zero temperature

Braiding Majorana zero-modes around each other is a promising route towards topological quantum computing. Yet, two competing maxims emerge when implementing Majorana braiding in real systems: On the one hand, perfect braiding should be conducted adiabatically slowly to avoid non-topological errors. On the other hand, braiding must be conducted fast such that decoherence effects introduced by the environment are negligible, which are generally unavoidable in finite-size systems. This competition results in an intermediate time scale for Majorana braiding that is optimal, but generally not error-free. Here, we calculate this intermediate time scale for a T-junction of short one-dimensional topological superconductors coupled to a bosonic bath that generates fluctuations in the local electric potential, which stem from, e.g., environmental photons or phonons of the substrate. We thereby obtain boundaries for the speed of Majorana braiding with a predetermined gate fidelity. Our results emphasize the general susceptibility of Majorana-based information storage in finite-size systems and can serve as a guide for determining the optimal braiding times in future experiments.

Controlling dynamical entanglement in a Josephson tunneling junction

We analyze the evolution of an entangled many-body state in a Josephson tunneling junction and its dependence on the number of bosons and interaction strength. A N00N state, which is a superposition of two complementary Fock states, appears in the evolution with sufficient probability only for a moderate many-body interaction on an intermediate time scale. This time scale is inversely proportional to the tunneling rate. Many-body interaction strongly supports entanglement: The probability for creating an entangled state decays exponentially with the number of particles without many-body interaction, whereas it decays only like the inverse square root of the number of particles in the presence of many-body interaction.

Incompressible impulsive sloshing

The incompressible impulsive time scale for inviscid liquid sloshing in open rigid containers suddenly put into motion is defined as the intermediate time scale in between the acoustic time scale and the gravitational time scale. Surge and sway boundary-value problems for incompressible impulsive sloshing in some realistic container shapes are solved analytically to the leading order in a small-time expansion. A solution is provided for two types of horizontal cylinders: a triangular cylindrical wedge and a half-filled circular cylinder. The surface velocity and the hydrodynamic force with its corresponding virtual fluid mass are calculated. The cases of constant impulsive velocity and constant impulsive acceleration are linked by transformation equations. Flows with waterline singularities are discussed, being leading-order outer flows in terms of matched asymptotic expansions.

FOOD QUALITY GENES AND GENETIC MODIFICATION OF FRUIT AND VEGETABLE PRODUCE

For many branded food products, the raw material is purchased as a commodity. Food companies provide added-value based on processing technology or marketing. The tools of plant biotechnology, which shorten the time for crop improvement and permit development of novel germplasm, offer the food industry the opportunity to modify raw materials and develop proprietary branded products. Such modifications will permit development of plant cultivars specifically selected for traits with added-value for the processor or the consumer. Biotechnology-developed cultivars offer the opportunity to develop produce that can be branded. The cell genetics tools of clonal propagation, somaclonal variation, gametoclonal variation, and protoplast fusion permit new cultivar development in an intermediate time scale, making them attractive for market introduction of proprietary products. When integrated with conventional breeding, these intermediate-term technologies will permit modification of fruits and vegetables over the course of the next several years. The longer-term technologies of plant genetic engineering will continue to have an impact on manipulation of specific traits, resulting in second-generation products specifically designed for consumers.

Bimodality of evolutionary rates

A simple theoretical argument shows that the evolutionary process will look gradual if it is considered on too fine or too coarse a time scale. There exists an intermediate time scale in which the distribution of evolutionary rates will appear as bimodal.