1,104 research outputs found
Polarization of electric field noise near metallic surfaces
Electric field noise in proximity to metallic surfaces is a poorly understood
phenomenon that appears in different areas of physics. Trapped ion quantum
information processors are particular susceptible to this noise, leading to
motional decoherence which ultimately limits the fidelity of quantum
operations. On the other hand they present an ideal tool to study this effect,
opening new possibilities in surface science. In this work we analyze and
measure the polarization of the noise field in a micro-fabricated ion trap for
various noise sources. We find that technical noise sources and noise emanating
directly from the surface give rise to different degrees of polarization which
allows us to differentiate between the two noise sources. Based on this, we
demonstrate a method to infer the magnitude of surface noise in the presence of
technical noise
Two mode coupling in a single ion oscillator via parametric resonance
Atomic ions, confined in radio-frequency Paul ion traps, are a promising
candidate to host a future quantum information processor. In this letter, we
demonstrate a method to couple two motional modes of a single trapped ion,
where the coupling mechanism is based on applying electric fields rather than
coupling the ion's motion to a light field. This reduces the design constraints
on the experimental apparatus considerably. As an application of this
mechanism, we cool a motional mode close to its ground state without accessing
it optically. As a next step, we apply this technique to measure the mode's
heating rate, a crucial parameter determining the trap quality. In principle,
this method can be used to realize a two-mode quantum parametric amplifier.Comment: 8 pages, 5 figure
Looking left or looking right?
The perception of political messages may not only be shaped by textual information, but also by its visual appearance. An online experiment investigated how newspaper articles’ layout style and text slant affect the perception of a newspapers’ political orientation on the left-right axis. The layout versions were based on a prior analysis of correlations between design and political direction of quality newspapers. Results suggest the existence of political layout effects: a conservative layout style led to the source of a left-wing slanted text being estimated more right-wing, especially for left-wing-oriented participants. However, it had no effect when it was combined congruently with a right-wing slanted text. A progressive layout style had only an effect for participants with more knowledge on quality newspapers, leading them to locate the source more left-wing
Lifetime development of behavioural phenotype in the house mouse (Mus musculus)
Brust V, Schindler PM, Lewejohann L. Lifetime development of behavioural phenotype in the house mouse (Mus musculus). Frontiers in Zoology. 2015;12(Suppl. 1): S17.With each trajectory taken during the ontogeny of an individual, the number of optional behavioural phenotypes
that can be expressed across its life span is reduced. The initial range of phenotypic plasticity is largely determined
by the genetic material/composition of the gametes whereas interacting with the given environment shapes
individuals to adapt to/cope with specific demands. In mammalian species, the phenotype is shaped as the foetus
grows, depending on the environment in the uterus, which in turn depends on the outer environment the mother
experiences during pregnancy. After birth, a complex interaction between innate constitution and environmental
conditions shapes individual lifetime trajectories, bringing about a wide range of diversity among individual
subjects.
In laboratory mice inbreeding has been systematically induced in order to reduce the genetic variability between
experimental subjects. In addition, within most laboratories conducting behavioural phenotyping with mice,
breeding and housing conditions are highly standardised. Despite such standardisation efforts a considerable
amount of variability persists in the behaviour of mice. There is good evidence that phenotypic variation is not
merely random but might involve individual specific behavioural patterns consistent over time. In order to
understand the mechanisms and the possible adaptive value of the maintenance of individuality we review the
emergence of behavioural phenotypes over the course of the life of (laboratory) mice. We present a literature
review summarizing developmental stages of behavioural development of mice along with three illustrative case
studies. We conclude that the accumulation of environmental differences and experiences lead to a
“mouse individuality” that becomes increasingly stable over the lifetime
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