A5055387102- Quantum Information and Cryptography
- Graphene research and applications
- Quantum Mechanics and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Semiconductor materials and devices
- Quantum and electron transport phenomena
- Graphene and Nanomaterials Applications
- Quantum Computing Algorithms and Architecture
- Advancements in Battery Materials
- Magnetic properties of thin films
- Boron and Carbon Nanomaterials Research
- Advancements in Semiconductor Devices and Circuit Design
- Advanced Memory and Neural Computing
- Magnetic Properties and Applications
- Electron and X-Ray Spectroscopy Techniques
- Carbon Nanotubes in Composites
- Advanced NMR Techniques and Applications
- Ion-surface interactions and analysis
- 2D Materials and Applications
- Silicon and Solar Cell Technologies
- Semiconductor materials and interfaces
- Neural Networks and Applications
- Optical properties and cooling technologies in crystalline materials
- Spectroscopy and Quantum Chemical Studies
- Radiation Effects in Electronics
Georgia Tech Research Institute
2021-2024
Georgia Institute of Technology
2010-2024
University of Maryland, College Park
2014-2016
Entanglement generation in trapped-ion systems has relied thus far on two distinct but related geometric phase gate techniques: Molmer-Sorensen and light-shift gates. We recently proposed a variant of the scheme where qubit levels are separated by an optical frequency [B. C. Sawyer K. R. Brown, Phys. Rev. A 103, 022427 (2021)]. Here we report experimental demonstration this entangling using pair $^{40}$Ca$^+$ ions cryogenic surface-electrode ion trap commercial, high-power, 532 nm Nd:YAG...
Abstract The trapped-ion quantum charge-coupled device (QCCD) architecture is a leading candidate for advanced information processing. In current QCCD implementations, imperfect ion transport and anomalous heating can excite motion during calculation. To counteract this, intermediate cooling necessary to maintain high-fidelity gate performance. Cooling the computational ions sympathetically with of another species, commonly employed strategy, creates significant runtime bottleneck. Here, we...
We review the progress towards developing epitaxial graphene as a material for carbon electronics. In particular, we discuss improvements in growth, interface control and understanding of multilayer graphene's (MEG's) electronic properties. Although grown on both polar faces SiC will be discussed, our discussions focus C-face SiC. The unique properties MEG have become apparent. These films behave electronically like stack nearly independent sheets rather than thin Bernal stacked graphite...
We investigate the origin of purported “spin accumulation” signals observed in local “three-terminal” (3T) measurements ferromagnet/insulator/n-Si tunnel junctions using inelastic electron tunneling spectroscopy (IETS). Voltage bias and magnetic field dependences IET spectra were found to account for dominant contribution 3T magnetoresistance, thus indicating that it arises from through impurities defects at junction interfaces within barrier, rather than spin accumulation due pure elastic...
We report on the temperature dependence of spin-pumping effect and Gilbert damping in Co/Pt bilayers grown Silicon oxide by measuring change linewidth a ferromagnetic resonance (FMR) experiment. By varying Co thickness d(Co) between 1.5 nm 50 we find that increases inversely proportional to at all temperatures 300 K 5 K, showing spin pumping does not depend temperature. also with decreasing for thicknesses down about 30 before leveling off constant, or even again. This behavior is similar...
Ion transport is an essential operation in some models of quantum information processing, where fast ion shuttling with minimal motional excitation necessary for efficient, high-fidelity logic. While and cold has been demonstrated, the dynamics specific trajectory during diabatic have not studied detail. Here we describe a position-dependent optical deshelving technique useful sampling ion's position throughout its trajectory, demonstrate on linear $^{40}\text{Ca}^+$ surface-electrode trap....
In this work we use LEEM, XPEEM and XPS to study how the excess Si at graphene-vacuum interface reorders itself high temperatures. We show that silicon deposited room temperature onto multilayer graphene films grown on SiC(000[`1]) rapidly diffuses graphene-SiC when heated temperatures above 1020. a sequence of depositions, have been able intercalate ~ 6 ML into interface.
We implement a two-qubit entangling M{\o}lmer-S{\o}rensen interaction by transporting two co-trapped $^{40}\mathrm{Ca}^{+}$ ions through stationary, bichromatic optical beam within surface-electrode Paul trap. describe procedure for achieving constant Doppler shift during the transport which uses fine temporal adjustment of moving confinement potential. The fixed duration transported laser as well dynamically changing ac Stark require alterations to calibration procedures used stationary...
We characterize multilayer graphene grown on C-face SiC before and after exposure to a total ionizing dose of 12 Mrad(SiO2) using 10 keV x-ray source. While we observe the partial peeling top layers appearance modest Raman D-peak, find that electrical characteristics (mobility, sheet resistivity, free carrier concentration) material are mostly unaffected by radiation exposure. Combined with photoelectron spectroscopy data showing numerous carbon-oxygen bonds irradiation, conclude primary...
Spin accumulation in a paramagnetic semiconductor due to voltage-biased current tunneling from polarized ferromagnet is experimentally manifest as small additional spin-dependent resistance. We describe rigorous model incorporating the necessary self-consistency between electrochemical potential splitting, injection current, and applied voltage that can be used simulate this so-called ``$3T$'' signal function of temperature, doping, bulk spin polarization, tunnel barrier features conduction...
We present a framework for quantum process tomography of two-ion interactions that leverages modulations the trapping potential and composite pulses from global laser beam to achieve individual-ion addressing. Tomographic analysis identity delay processes reveals dominant error contributions decoherence slow qubit frequency drift during experiment. use this on two co-trapped $^{40}$Ca$^+$ ions analyze both an optimized overpowered Mølmer-Sørensen gate compare results less informative...
The trapped-ion quantum charge-coupled device (QCCD) architecture is a leading candidate for advanced information processing. In current QCCD implementations, imperfect ion transport and anomalous heating can excite motion during calculation. To counteract this, intermediate cooling necessary to maintain high-fidelity gate performance. Cooling the computational ions sympathetically with of another species, commonly employed strategy, creates significant runtime bottleneck. Here, we...
Several recent measurements of magnetoresistance in ferromagnet/insulator/semiconductor tunnel junctions have led to controversial claims spin accumulation, where the signal amplitude and derived relaxation time often deviates from theoretically calculated experimentally confirmed values by several orders magnitude. These discrepancies cast doubt on physical origin measured magnetoresistance, which was initially attributed precession dephasing semiconductor. More recently, models...
Ion transport is an essential operation in some models of quantum information processing, where fast ion shuttling with minimal motional excitation necessary for efficient, high-fidelity logic. While and cold has been demonstrated, the dynamics specific trajectory during diabatic have not studied detail. Here we describe a position-dependent optical deshelving technique useful sampling ion's position throughout its trajectory, demonstrate on linear $^{40}\text{Ca}^+$ surface-electrode trap....
We review progress in developing epitaxial graphene as a material for carbon electronics. In particular, improvements growth, interface control and the understanding of multilayer graphene's electronic properties are discussed. Although grown on both polar faces SiC is addressed, our discussions will focus (000-1) C-face SiC. The unique have become apparent. These films behave electronically like stack nearly independent sheets rather than thin Bernal-stacked graphite sample. origin behavior...