5,260 research outputs found
Creation of two-dimensional coulomb crystals of ions in oblate Paul traps for quantum simulations
We develop the theory to describe the equilibrium ion positions and phonon
modes for a trapped ion quantum simulator in an oblate Paul trap that creates
two-dimensional Coulomb crystals in a triangular lattice. By coupling the
internal states of the ions to laser beams propagating along the symmetry axis,
we study the effective Ising spin-spin interactions that are mediated via the
axial phonons and are less sensitive to ion micromotion. We find that the axial
mode frequencies permit the programming of Ising interactions with inverse
power law spin-spin couplings that can be tuned from uniform to with
DC voltages. Such a trap could allow for interesting new geometrical
configurations for quantum simulations on moderately sized systems including
frustrated magnetism on triangular lattices or Aharonov-Bohm effects on ion
tunneling. The trap also incorporates periodic boundary conditions around loops
which could be employed to examine time crystals.Comment: 17 pages, 8 figures, submitted to the journal EPJ Quantum Technology
for the thematic Series on Quantum Simulation
Cold molecular ions on a chip
We report the sympathetic cooling and Coulomb crystallization of molecular
ions above the surface of an ion-trap chip. N and CaH ions were
confined in a surface-electrode radiofrequency ion trap and cooled by the
interaction with laser-cooled Ca ions to secular translational
temperatures in the millikelvin range. The configuration of trapping potentials
generated by the surface electrodes enabled the formation of planar bicomponent
Coulomb crystals and the spatial separation of the molecular from the atomic
ions on the chip. The structural and thermal properties of the Coulomb crystals
were characterized using molecular dynamics simulations. The present study
extends chip-based trapping techniques to Coulomb-crystallized molecular ions
with potential applications in mass spectrometry, cold chemistry, quantum
information science and spectroscopy.Comment: 5 pages, 4 figure
Simulating open quantum systems: from many-body interactions to stabilizer pumping
In a recent experiment, Barreiro et al. demonstrated the fundamental building
blocks of an open-system quantum simulator with trapped ions [Nature 470, 486
(2011)]. Using up to five ions, single- and multi-qubit entangling gate
operations were combined with optical pumping in stroboscopic sequences. This
enabled the implementation of both coherent many-body dynamics as well as
dissipative processes by controlling the coupling of the system to an
artificial, suitably tailored environment. This engineering was illustrated by
the dissipative preparation of entangled two- and four-qubit states, the
simulation of coherent four-body spin interactions and the quantum
non-demolition measurement of a multi-qubit stabilizer operator. In the present
paper, we present the theoretical framework of this gate-based ("digital")
simulation approach for open-system dynamics with trapped ions. In addition, we
discuss how within this simulation approach minimal instances of spin models of
interest in the context of topological quantum computing and condensed matter
physics can be realized in state-of-the-art linear ion-trap quantum computing
architectures. We outline concrete simulation schemes for Kitaev's toric code
Hamiltonian and a recently suggested color code model. The presented simulation
protocols can be adapted to scalable and two-dimensional ion-trap
architectures, which are currently under development.Comment: 27 pages, 9 figures, submitted to NJP Focus on Topological Quantum
Computatio
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