53 research outputs found
Dissipative quantum control of a spin chain
A protocol is discussed for preparing a spin chain in a generic many-body
state in the asymptotic limit of tailored non-unitary dynamics. The dynamics
require the spectral resolution of the target state, optimized coherent pulses,
engineered dissipation, and feedback. As an example, we discuss the preparation
of an entangled antiferromagnetic state, and argue that the procedure can be
applied to chains of trapped ions or Rydberg atoms.Comment: 5 pages, 4 figure
Quantum simulation of the hexagonal Kitaev model with trapped ions
We present a detailed study of quantum simulations of coupled spin systems in
surface-electrode ion-trap arrays, and illustrate our findings with a proposed
implementation of the hexagonal Kitaev model [A. Kitaev, Annals of Physics
321,2 (2006)]. The effective (pseudo)spin interactions making up such quantum
simulators are found to be proportional to the dipole-dipole interaction
between the trapped ions, and are mediated by motion which can be driven by
state-dependent forces. The precise forms of the trapping potentials and the
interactions are derived in the presence of a surface electrode and a cover
electrode. These results are the starting point to derive an optimized
surface-electrode geometry for trapping ions in the desired honeycomb lattice
of Kitaev's model, where we design the dipole-dipole interactions in a way that
allows for coupling all three bond types of the model simultaneously, without
the need for time discretization. Finally we propose a simple wire structure
that can be incorporated in a microfabricated chip to generate localized
state-dependent forces which drive the couplings prescribed by this particular
model; such a wire structure should be adaptable to many other situations.Comment: 24 pages, 7 figures. v2: simplified the derivation of (28) without
changing conclusions; minor edits. v3: minor edit
Quantum walk on a line for a trapped ion
We show that a multi-step quantum walk can be realized for a single trapped
ion with interpolation between quantum and random walk achieved by randomizing
the generalized Hadamard coin flip phase. The signature of the quantum walk is
manifested not only in the ion's position but also its phonon number, which
makes an ion trap implementation of the quantum walk feasible.Comment: 5 pages, 3 figure
Trap-Integrated Superconducting Nanowire Single-Photon Detectors with Improved RF Tolerance for Trapped-Ion Qubit State Readout
State readout of trapped-ion qubits with trap-integrated detectors can
address important challenges for scalable quantum computing, but the strong rf
electric fields used for trapping can impact detector performance. Here, we
report on NbTiN superconducting nanowire single-photon detectors (SNSPDs)
employing grounded aluminum mirrors as electrical shielding that are integrated
into linear surface-electrode rf ion traps. The shielded SNSPDs can be
successfully operated at applied rf trapping potentials of up to
at and temperatures of up to
, with a maximum system detection efficiency of
. This performance should be sufficient to enable parallel
high-fidelity state readout of a wide range of trapped ion species in typical
cryogenic apparatus.Comment: 6 pages, 4 figures. The following article has been submitted to
Applied Physics Letter
- …