Nonadiabatic Geometric Quantum Computation Using A Single-loop Scenario

A single-loop scenario is proposed to realize nonadiabatic geometric quantum computation. Conventionally, a so-called multi-loop approach is used to remove the dynamical phase accumulated in the operation process for geometric quantum gates. More intriguingly, we here illustrate in detail how to use a special single-loop method to remove the dynamical phase and thus to construct a set of universal quantum gates based on the nonadiabatic geometric phase shift. The present scheme is applicable to NMR systems and may be feasible in other physical systems.Comment: 4 pages, 3 figure

Chaotic Properties of Subshifts Generated by a Non-Periodic Recurrent Orbit

The chaotic properties of some subshift maps are investigated. These subshifts are the orbit closures of certain non-periodic recurrent points of a shift map. We first provide a review of basic concepts for dynamics of continuous maps in metric spaces. These concepts include nonwandering point, recurrent point, eventually periodic point, scrambled set, sensitive dependence on initial conditions, Robinson chaos, and topological entropy. Next we review the notion of shift maps and subshifts. Then we show that the one-sided subshifts generated by a non-periodic recurrent point are chaotic in the sense of Robinson. Moreover, we show that such a subshift has an infinite scrambled set if it has a periodic point. Finally, we give some examples and discuss the topological entropy of these subshifts, and present two open problems on the dynamics of subshifts

Erosion-induced massive organic carbon burial and carbon emission in the Yellow River basin, China

Soil erosion and terrestrial deposition of soil organic carbon (SOC) can potentially play a significant role in global carbon cycling. Assessing the redistribution of SOC during erosion and subsequent transport and burial is of critical importance. Using hydrological records of soil erosion and sediment load, and compiled organic carbon (OC) data, estimates of the eroded soils and OC induced by water in the Yellow River basin during the period 1950–2010 were assembled. The Yellow River basin has experienced intense soil erosion due to combined impact of natural process and human activity. Over the period, 134.2 ± 24.7 Gt of soils and 1.07 ± 0.15 Gt of OC have been eroded from hillslopes based on a soil erosion rate of 1.7–2.5 Gt yr⁻¹. Approximately 63% of the eroded soils were deposited in the river system, while only 37% were discharged into the ocean. For the OC budget, approximately 0.53 ± 0.21 Gt (49.5%) was buried in the river system, 0.25 ± 0.14 Gt (23.5%) was delivered into the ocean, and the remaining 0.289 ± 0.294 Gt (27%) was decomposed during the erosion and transport processes. This validates the commonly held assumption that 20–40% of the eroded OC would be oxidized after erosion. Erosion-induced OC redistribution on the landscape likely represented a carbon source, although a large proportion of OC was buried. In addition, about half of the terrestrially redeposited OC (49.4%) was buried behind dams, revealing the importance of dam trapping in sequestering the eroded OC. Although several uncertainties need to be better constrained, the obtained budgetary results provide a means of assessing the redistribution of the eroded OC within the Yellow River basin. Human activities have significantly altered its redistribution pattern over the past decades

Mineralogical and geochemical study of carp otoliths from Baiyangdian Lake and Miyun Water Reservoir in China

Carp otoliths from two different freshwaters (Baiyangdian Lake and Miyun Water Reservoir) were mineralogically and chemically analyzed. The water quality standard of Miyun Water Reservoir is Grade 2 which is much better than the Grade 5 of Baiyangdian Lake. The aim of this study was to examine the differences in otoliths in mineralogy and chemistry from the two sites with quite different qualities. All the analyzed carps showed lapillus and sagitta otoliths made of aragonite, except for B-22 (from Baiyangdian Lake) whose lapillus consisted of vaterite and sagitta consisted of aragonite and vaterite; all asteriscus are composed of vaterite. It is inferred that the occurrence of vaterictic otoliths is linked to poor water quality. Chemical analysis showed that significant difference of Pb concentration between sites was tested by t-test of the compare means (t-test comparison: t = 2.043, P<0.05). While the sitespecific differences of the other metals were not significant. In addition, a significant difference of Sn concentration was tested as well (t-test comparison: t = 2.652, P<0.05). Average content of lapilli Pb is consistent with the water dissolved Pb measurement, with higher dissolved Pb concentration in Baiyangdian Lake relative to the Miyun Water Reservoir.Key words: Carp otoliths, water quality, mineralogy, chemistry, Pb