On universal decoherence under gravity: a perspective through the Equivalence Principle

In Nature Phys. 11, 668 (2015) (Ref. [1]), a composite particle prepared in a pure initial quantum state and propagated in a uniform gravitational field is shown to undergo a decoherence process at a rate determined by the gravitational acceleration. By assuming Einstein's Equivalence Principle to be valid, we demonstrate, first in a Lorentz frame with accelerating detectors, and then directly in the Lab frame with uniform gravity, that the dephasing between the different internal states arise not from gravity but rather from differences in their rest mass, and the mass dependence of the de Broglie wave's dispersion relation. We provide an alternative view to the situation considered by Ref. [1], where we propose that gravity plays a kinematic role in the loss of fringe visibility by giving the detector a transverse velocity relative to the particle beam; visibility can be easily recovered by giving the screen an appropriate uniform velocity. We finally propose that dephasing due to gravity may in fact take place for certain modifications to the gravitational potential where the Equivalence Principle is violated.Comment: 5 pages, 3 figure

LC decoupling circuit for arbitrarily placed coils

published_or_final_versio

Carbon and Nitrogen Pools in Soil Aggregates Were Affected by Grazing Component ---- Results from Dry and Wet Sieving Methods

Grazing intensity can affect soil carbon (C) sequestration in semiarid grassland, but less is known about the effects of grazing component (defoliation, trampling, excreta return and their combinations) on the C and Nitrogen (N) in soil aggregates. In this study, a simulated grazing experiment was established in a typical steppe of Inner Mongolia, and we investigated the impacts of different grazing component treatments on the different size of aggregates distribution and their C and N content from dry and wet physical separations. Different soil C fractions were showed in different sieving method. The C content of different aggregate size showed microaggregates (250-53μm, 7-17%)\u3emacroaggregates (\u3e250μm, 4-12%) \u3efine fraction (\u3c53μm, 0.4-3%) when dry sieving method was performed, but wet sieving resulted in the higher C content in microaggregates (6-14%) and fine fraction (5-11%) than macroaggregates (1-5%). N content of different size of aggregates showed similar trend with C content. The results revealed that grazing component had a marked impact on soil fraction and C and N content with the significant decreasing percentage of macroaggregates and their C and N storage under defoliation. Our result indicated that both dry-sieved aggregates and water-stable aggregates should be concerned to evaluate the short-term grazing disturbance on C and N distribution in soil aggregates. Furthermore, we suggest that trampling is critical for the soil compaction, but defoliation may play a more important role in soil aggregation and C storage in grazing grassland

Compensation for mutual coupling in transmit SENSE

Transmit SENSE has been developed to decrease the RF excitation duration by using a transmit coil array. In this work, mutual coupling between coils is taken into account by introducing a coupling coefficient matrix into the central equation of transmit SENSE. Simulations demonstrate that this method is effective to compensate for aliasing artifacts in transmit SENSE.published_or_final_versio

Modified microstrip volume coil for ultrahigh field

It is a challenge to design a lumped-element microstrip volume resonator at ultrahigh field (>7T) with large size. A new modified microstrip volume coil with large coil dimension (o.d.=18cm) and coil thickness (3.3cm) is fabricated, tested and simulated in this paper. Through deploying ground line at the back of each strip line, this modified microstrip resonator can be easily tuned to 300MHz.published_or_final_versio