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Control Barrier Function (CBF) is an emerging method that guarantees safety in path planning problems by generating a control command to ensure the forward invariance of a safety set. Most of the developments up to date assume availability…
We report an ultrafast optical spectroscopy study on the coherent phonon dynamics in the topological semimetal CeBi and its nonmagnetic isostructural compound LaBi, revealing profound insights into their electronic and magnetic…
We propose and demonstrate a relaxed-SiGe/strained-Si (SiGe/s-Si) enhancement-mode gate stack for quantum dots. The enhancement-mode SiGe/s-Si structure is pursued because it spaces the quantum dot away from charge and spin defect rich…
The Belle II experiment at the SuperKEKB electron-positron collider aims to collect an unprecedented data set of $\rm 50~{\rm ab}^{-1}$ to study $CP$-violation in the $B$-meson system and to search for Physics beyond the Standard Model…
We report on the SuperKEKB Phase I operations of the Large Angle Beamstrhalung Monitor (LABM). The detector is described and its performance characterized using the synchrotron radiation backgrounds from the last Beam Line magnets. The…
Collimator wakefields in the Beam Delivery System (BDS) of future linear colliders, such as the International Linear Collider (ILC) and the Compact Linear Collider (CLIC), can be an important source of emittance growth and beam jitter…
The crab-waist collision scheme has been the baseline choice for SuperKEKB and future circular $e^+e^-$ colliders. Achieved through properly phased sextupoles, the crab-waist transform is essential in suppressing beam-beam resonances,…
We report on the realization of a superinductor, a dissipationless element whose microwave impedance greatly exceeds the resistance quantum. The design of the superinductor, implemented as a ladder of nanoscale Josephson junctions, enables…
In this paper, we study single-bunch instabilities observed in the CERN Super Proton Synchrotron (SPS). According to the linearized Vlasov theory, radial or azimuthal mode-coupling instabilities result from a coupling of bunch-oscillation…
Atomic layers deposited on semiconductor substrates introduce a platform for the realization of the extended electronic Hubbard model, where the consideration of electronic repulsion beyond the onsite term is paramount. Recently, the onset…
Recent research interest in emerging logic systems based on quantum dots has been sparked by the experimental demonstration of nanometer-scale logic devices composed of atomically sized quantum dots made of silicon dangling bonds (SiDBs),…
We investigate the non-equilibrium behavior of BCS superconductors subjected to slow ramps of their internal interaction strength. We identify three dynamical regimes as a function of ramp duration. For short ramp times, these systems…
Dielectric properties of semiconductor substrate with imposed two dimensional (2D) periodic grid of quantum wires or nanotubes (quantum crossbars, QCB) are studied. It is shown that a capacitive contact between QCB and semiconductor…
KEK-ATF is doing R&D establishing high-current and low-emittance electron beam for the future linear colliders. In ATF, 15 ps length electron beam is generated by combination of a thermionic gun, a couple of 357 MHz SHBs, and a S-band TW…
This article reviews the beam dynamics issues, such as intra-beam scattering, beam-beam interaction, lattice nonlinearity, and space charge, in SuperKEKB before its commissioning.
We present a new symmetry-based concept for an achromatic low-beta collider interaction region design. A specially-designed symmetric Chromaticity Compensation Block (CCB) induces an angle spread in the passing beam such that it cancels the…
A beam position monitor (BPM) upgrade at the KEK Accelerator Test Facility (ATF) damping ring has been accomplished, carried out by a KEK/FNAL/SLAC collaboration under the umbrella of the global ILC R&D effort. The upgrade consists of a…
In DAFNE, the Frascati $e^+e^-$ collider operating since 1998, an innovative collision scheme, the crab waist, has been successfully implemented during the years 2008-09. During operations for the Siddharta experiment an unusual synchrotron…
We investigate the instabilities that may lead to the breakdown of the Luttinger liquid in the small-diameter (5,0) nanotubes, paying attention to the competition between the effective interaction mediated by phonon-exchange and the Coulomb…
This work presents a safe control design approach that integrates the disturbance observer (DOB) and the control barrier function (CBF) for systems with external disturbances. Different from existing robust CBF results that consider the…