Dependence of the 0.5(2e2/h) conductance plateau on the aspect ratio of InAs quantum point contacts with in-plane side gates

The observation of a 0.5 conductance plateau in asymmetrically biased quantum point contacts with in-plane side gates has been attributed to the onset of spin-polarized current through these structures. For InAs quantum point contacts with the same width but longer channel length, there is roughly a fourfold increase in the range of common sweep voltage applied to the side gates over which the 0.5 conductance plateau is observed when the QPC aspect ratio (ratio of length over width of the narrow portion of the structure) is increased by a factor 3. Non-equilibrium Green s function simulations indicate that the increase in the size of the 0.5 conductance plateau is due to an increased importance, over a larger range of common sweep voltage, of the effects of electron-electron interactions in QPC devices with larger aspect ratio. The use of asymmetrically biased QPCs with in-plane side gates and large aspect ratio could therefore pave the way to build robust spin injectors and detectors for the successful implementation of spin field effect transistorsComment: 30 pages, 9 figure

Isotope Shifts in the 7 s → 8 s Transition of Francium: Measurements and Comparison to ab initio Theory

We observe the electric-dipole forbidden 7s→8s transition in the francium isotopes 208−211Fr and 213Fr using a two-photon excitation scheme. We collect the atoms online from an accelerator and confine them in a magneto-optical trap for the measurements. In combination with previous measurements of the 7s→7p1/2 transition we perform a King plot analysis. We compare the thus-determined ratio of the field shift constants (1.228 ± 0.019) to results obtained from new ab initio calculations (1.234 ± 0.010)

Eating from the wild: an insight into the indigenous wild edible plants consumed by the Digaru Mishmi tribe of Arunachal Pradesh

Anjaw district is situated at the extreme foothill of eastern himalaya of Arunachal Pradesh, distinctive in its nature by having a rich diversity of wild edible plants rich in nutrition as well as medicinal properties. Ethnically, the Digaru Mishmi tribe (inhabitants) of the district adopted the traditional way of consuming these rich ethnobotanical resources to fulfill their daily nutrition & health care. These plants have traditionally occupied an important position in their socio-cultural, spiritual and health aspects of the rural tribal lives. So, the consumption of wild edible plants as a food source has been an integral part of the indigenous people’s culture. To get an insight into the Digaru Mishmi people’s way of lifestyle, the present study was conducted to explore, identify & document the ethno botany of the Digaru Mishmi people and to record their unique knowledge about wild edible plants. Around 57 species were found & all the plants used by the tribe are tabulated inalphabetical order along with botanical name, vernacular name (Digaru Mishmi), family, parts used, food value and ethnomedicinal uses. Wild edible plants form a good source of protein, fat, vitamins, sugar and minerals requirement of the tribal people to a greater extent. Hence, the paper highlights the identification diversity of wild edible plants andits documentation

First Measurement of the Atomic Electric Dipole Moment of \u3csup\u3e225\u3c/sup\u3eRa

The radioactive radium-225 (225Ra) atom is a favorable case to search for a permanent electric dipole moment. Because of its strong nuclear octupole deformation and large atomic mass, 225Ra is particularly sensitive to interactions in the nuclear medium that violate both time-reversal symmetry and parity. We have developed a cold-atom technique to study the spin precession of 225Ra atoms held in an optical dipole trap, and demonstrated the principle of this method by completing the first measurement of its atomic electric dipole moment, reaching an upper limit of |d(225Ra)|\u3c5.0×10−22  e cm (95% confidence)

Sub- and above barrier fusion of loosely bound 6^6Li with 28^{28}Si

Fusion excitation functions are measured for the system $^6$Li+$^{28}$Si using the characteristic $\gamma$-ray method, encompassing both the sub-barrier and above barrier regions, viz., $E_{lab}$= 7-24 MeV. Two separate experiments were performed, one for the above barrier region ($E_{lab}$= 11-24 MeV) and another for the below barrier region ($E_{lab}$= 7-10 MeV). The results were compared with our previously measured fusion cross section for the $^7$Li+$^{28}$Si system. We observed enhancement of fusion cross section at sub-barrier regions for both $^6$Li and $^7$Li, but yield was substantially larger for $^6$Li. However, for well above barrier regions, similar type of suppression was identified for both the systems.Comment: 8 pages, 6 figures, as accepted for publication in Eur.Phys.J.

Evidence for Cold-stream to Hot-accretion Transition as Traced by Ly alpha Emission from Groups and Clusters at 2 < z < 3.3

We present Keck Cosmic Web Imager observations of giant Ly alpha halos surrounding nine galaxy groups and clusters at 2 < z < 3.3, including five new detections and one upper limit. We find observational evidence for the cold-stream to hot-accretion transition predicted by theory by measuring a decrease in the ratio between the spatially extended Ly alpha luminosity and the expected baryonic accretion rate (BAR), with increasing elongation above the transition mass (M-stream). This implies a modulation of the share of BAR that remains cold, diminishing quasi-linearly (logarithmic slope of 0.97 +/- 0.19, 5 sigma significance) with the halo to M-stream mass ratio. The integrated star formation rates (SFRs) and active galactic nucleus (AGN) bolometric luminosities display a potentially consistent decrease, albeit significant only at 2.6 sigma and 1.3 sigma, respectively. The higher scatter in these tracers suggests the Ly alpha emission might be mostly a direct product of cold accretion in these structures rather than indirect, mediated by outflows and photoionization from SFR and AGNs; this is also supported by energetics considerations. Below M-stream (cold-stream regime), we measure L (Ly alpha) /BAR = 10(40.51 +/- 0.16) erg s(-1) M-circle dot(-1) yr, consistent with predictions, and SFR/BAR = 10(-0.54 +/- 0.23): on average, 30(-10)(+20) M-stream (hot-accretion regime), L-Ly alpha is set by M-stream (within 0.2 dex scatter in our sample), independent of the halo mass but rising 10-fold from z = 2 to 3.Peer reviewe