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Strongly Anisotropic Spin and Orbital Rashba Effect at a Tellurium - Noble Metal Interface
Authors:
B. Geldiyev,
M. Ünzelmann,
P. Eck,
T. Kißlinger,
J. Schusser,
T. Figgemeier,
P. Kagerer,
N. Tezak,
M. Krivenkov,
A. Varykhalov,
A. Fedorov,
L. Nicolaï,
J. Minár,
K. Miyamoto,
T. Okuda,
K. Shimada,
D. Di Sante,
G. Sangiovanni,
L. Hammer,
M. A. Schneider,
H. Bentmann,
F. Reinert
Abstract:
We study the interplay of lattice, spin and orbital degrees of freedom in a two-dimensional model system: a flat square lattice of Te atoms on a Au(100) surface. The atomic structure of the Te monolayer is determined by scanning tunneling microscopy (STM) and quantitative low-energy electron diffraction (LEED-IV). Using spin- and angle-resolved photoelectron spectroscopy (ARPES) and density functi…
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We study the interplay of lattice, spin and orbital degrees of freedom in a two-dimensional model system: a flat square lattice of Te atoms on a Au(100) surface. The atomic structure of the Te monolayer is determined by scanning tunneling microscopy (STM) and quantitative low-energy electron diffraction (LEED-IV). Using spin- and angle-resolved photoelectron spectroscopy (ARPES) and density functional theory (DFT), we observe a Te-Au interface state with highly anisotropic Rashba-type spin-orbit splitting at the X point of the Brillouin zone. Based on a profound symmetry and tight-binding analysis, we show how in-plane square lattice symmetry and broken inversion symmetry at the Te-Au interface together enforce a remarkably anisotropic orbital Rashba effect which strongly modulates the spin splitting.
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Submitted 4 August, 2023;
originally announced August 2023.
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Demonstration of Universal Parametric Entangling Gates on a Multi-Qubit Lattice
Authors:
M. Reagor,
C. B. Osborn,
N. Tezak,
A. Staley,
G. Prawiroatmodjo,
M. Scheer,
N. Alidoust,
E. A. Sete,
N. Didier,
M. P. da Silva,
E. Acala,
J. Angeles,
A. Bestwick,
M. Block,
B. Bloom,
A. Bradley,
C. Bui,
S. Caldwell,
L. Capelluto,
R. Chilcott,
J. Cordova,
G. Crossman,
M. Curtis,
S. Deshpande,
T. El Bouayadi
, et al. (34 additional authors not shown)
Abstract:
We show that parametric coupling techniques can be used to generate selective entangling interactions for multi-qubit processors. By inducing coherent population exchange between adjacent qubits under frequency modulation, we implement a universal gateset for a linear array of four superconducting qubits. An average process fidelity of $\mathcal{F}=93\%$ is estimated for three two-qubit gates via…
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We show that parametric coupling techniques can be used to generate selective entangling interactions for multi-qubit processors. By inducing coherent population exchange between adjacent qubits under frequency modulation, we implement a universal gateset for a linear array of four superconducting qubits. An average process fidelity of $\mathcal{F}=93\%$ is estimated for three two-qubit gates via quantum process tomography. We establish the suitability of these techniques for computation by preparing a four-qubit maximally entangled state and comparing the estimated state fidelity against the expected performance of the individual entangling gates. In addition, we prepare an eight-qubit register in all possible bitstring permutations and monitor the fidelity of a two-qubit gate across one pair of these qubits. Across all such permutations, an average fidelity of $\mathcal{F}=91.6\pm2.6\%$ is observed. These results thus offer a path to a scalable architecture with high selectivity and low crosstalk.
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Submitted 26 February, 2018; v1 submitted 20 June, 2017;
originally announced June 2017.
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Spectral properties of finite laser-driven lattices of ultracold Rydberg atoms
Authors:
Nikolas Tezak,
Michael Mayle,
Peter Schmelcher
Abstract:
We investigate the spectral properties of a finite laser-driven lattice of ultracold Rydberg atoms exploiting the dipole blockade effect in the frozen Rydberg gas regime. Uniform one-dimensional lattices as well as lattices with variable spacings are considered. In the case of a weak laser coupling, we find a multitude of many-body Rydberg states with well-defined excitation properties which are a…
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We investigate the spectral properties of a finite laser-driven lattice of ultracold Rydberg atoms exploiting the dipole blockade effect in the frozen Rydberg gas regime. Uniform one-dimensional lattices as well as lattices with variable spacings are considered. In the case of a weak laser coupling, we find a multitude of many-body Rydberg states with well-defined excitation properties which are adiabatically accessible starting from the ground state. A comprehensive analysis of the degeneracies of the spectrum as well as of the single and pair excitations numbers of the eigenstates is performed. In the strong laser regime, analytical solutions for the pseudo-fermionic eigenmodes are derived. Perturbative energy corrections for this approximative approach are provided.
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Submitted 14 September, 2011; v1 submitted 17 December, 2010;
originally announced December 2010.