1,422 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
Everything Everywhere All At Once: A First Principles Numerical Demonstration of Emergent Decoherent Histories
Within the histories formalism the decoherence functional is a formal tool to
investigate the emergence of classicality in isolated quantum systems, yet an
explicit evaluation of it from first principles has not been reported. We
provide such an evaluation for up to five-time histories based on exact
numerical diagonalization of the Schroedinger equation. We find a robust
emergence of decoherence for slow and coarse observables of a generic random
matrix model and extract a finite size scaling law by varying the Hilbert space
dimension over four orders of magnitude. Specifically, we conjecture and
observe an exponential suppression of coherent effects as a function of the
particle number of the system. This suggests a solution to the preferred basis
problem of the many worlds interpretation (or the set selection problem of the
histories formalism) within a minimal theoretical framework -- without relying
on environmentally induced decoherence, quantum Darwinism, Markov
approximations or ensemble averages. We further discuss the implications of our
results for the wave function of the Universe, interpretations of quantum
mechanics and the arrow(s) of time.Comment: 14 pages with 11 figures plus references. Substantially revised
presentation and discussion compared to v1 but the same main result
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