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  1. Abstract In two-dimensional (2D) NbSe 2 crystal, which lacks inversion symmetry, strong spin-orbit coupling aligns the spins of Cooper pairs to the orbital valleys, forming Ising Cooper pairs (ICPs). The unusual spin texture of ICPs can be further modulated by introducing magnetic exchange. Here, we report unconventional supercurrent phase in van der Waals heterostructure Josephson junctions (JJs) that couples NbSe 2 ICPs across an atomically thin magnetic insulator (MI) Cr 2 Ge 2 Te 6 . By constructing a superconducting quantum interference device (SQUID), we measure the phase of the transferred Cooper pairs in the MI JJ. We demonstrate a doubly degenerate nontrivial JJ phase ( ϕ ), formed by momentum-conserving tunneling of ICPs across magnetic domains in the barrier. The doubly degenerate ground states in MI JJs provide a two-level quantum system that can be utilized as a new dissipationless component for superconducting quantum devices. Our work boosts the study of various superconducting states with spin-orbit coupling, opening up an avenue to designing new superconducting phase-controlled quantum electronic devices.
    Free, publicly-accessible full text available December 1, 2022
  2. The field of Mechatronics and Robotics Engineering (MRE) is emerging as a distinct academic discipline. Previously, courses in this field have been housed in departments of Mechanical Engineering, Electrical Engineering, or Computer Science, instead of a standalone department or curriculum. More recently, single, freestanding courses have increasingly grown into course sequences and concentrations, with entire baccalaureate and graduate degree programs now being offered. The field has been legitimized in recent years with the National Center for Education Statistics creating the Classification of Instructional Programs (CIP) code 14.201 Mechatronics, Robotics, and Automation Engineering. As of October 2019, ABET accredits a total of 9 B.S. programs in the field: 5 Mechatronics Engineering, 3 Robotics Engineering, 1 Mechatronics and Robotics Engineering, and none in Automation Engineering. Despite recent tremendous and dynamic growth, MRE lacks a dedicated professional organization and has no discipline-specific ABET criteria. As the field grows more important and widespread, it becomes increasingly relevant to formalize and standardize the curricula of these programs. This paper begins a conversation about the contents of a cohesive concept inventory for MRE. The impetus for this effort grew from a set of four industry and government sponsored workshops held around the country named the Futuremore »of Mechatronics and Robotics Engineering (FoMRE). These workshops brought together multidisciplinary academic professionals and industry leaders in the field, and ran from September 2018 to September 2019. The study presented here focuses primarily on programs at the baccalaureate level, but informs discussion at the graduate level as well. A survey is prepared with lists of potential concept inventory items, and asks university faculty, students and practicing engineers to identify which concepts lie at the core of MRE. Because of the interdisciplinary nature of the field, a wide range of basic concepts including physical quantities and units, circuit analysis, digital logic, electronics, programming, computer-aided design, solid and fluid mechanics, chemistry, dynamic systems and controls, and mathematics are considered. Questions ask participants to rank the priority or importance of potential core concepts from these categories and also provide opportunities for open-ended response. The results of this survey identify gaps between existing undergraduate curricula, student experience, and employer expectations, and continuing work will provide insight into the direction of a unifying curricular design for MRE education.« less
  3. ABSTRACT We study the projected spatial offset between the ultraviolet continuum and Ly α emission for 65 lensed and unlensed galaxies in the Epoch of Reionization (5 ≤ z ≤ 7), the first such study at these redshifts, in order to understand the potential for these offsets to confuse estimates of the Ly α properties of galaxies observed in slit spectroscopy. While we find that ∼40 per cent of galaxies in our sample show significant projected spatial offsets ($|\Delta _{\rm {Ly}\alpha -\rm {UV}}|$), we find a relatively modest average projected offset of $|\widetilde{\Delta }_{\rm {Ly}\alpha -\rm {UV}}|$  = 0.61 ± 0.08 proper kpc for the entire sample. A small fraction of our sample, ∼10 per cent, exhibit offsets in excess of 2 proper kpc, with offsets seen up to ∼4 proper kpc, sizes that are considerably larger than the effective radii of typical galaxies at these redshifts. An internal comparison and a comparison to studies at lower redshift yielded no significant evidence of evolution of $|\Delta _{\rm {Ly}\alpha -\rm {UV}}|$ with redshift. In our sample, ultraviolet (UV)-bright galaxies ($\widetilde{L_{\mathrm{ UV}}}/L^{\ast }_{\mathrm{ UV}}=0.67$) showed offsets a factor of three greater than their fainter counterparts ($\widetilde{L_{\mathrm{ UV}}}/L^{\ast }_{\mathrm{ UV}}=0.10$), 0.89 ± 0.18 versus 0.27 ± 0.05 proper kpc, respectively. The presence of companion galaxies and early stage merging activitymore »appeared to be unlikely causes of these offsets. Rather, these offsets appear consistent with a scenario in which internal anisotropic processes resulting from stellar feedback, which is stronger in UV-brighter galaxies, facilitate Ly α fluorescence and/or backscattering from nearby or outflowing gas. The reduction in the Ly α flux due to offsets was quantified. It was found that the differential loss of Ly α photons for galaxies with average offsets is not, if corrected for, a limiting factor for all but the narrowest slit widths (<0.4 arcsec). However, for the largest offsets, if they are mostly perpendicular to the slit major axis, slit losses were found to be extremely severe in cases where slit widths of ≤1 arcsec were employed, such as those planned for James Webb Space Telescope/NIRSpec observations.« less