We report high-fidelity laser-beam-induced quantum logic gates on magnetic-field-insensitive qubits comprised of hyperfine states in $^{9}$Be$^+$ ions with a memory coherence time more than 1 s. demonstrate single-qubit error per gate $3.8(1)\times 10^{-5}$. By creating Bell state deterministic two-qubit gate, we deduce $8(4)\times10^{-4}$. characterize the errors our implementation and discuss methods to further reduce imperfections towards values that are compatible fault-tolerant...

We investigate the motional dynamics of single and multiple ions during transport between separation into spatially distinct locations in a multi-zone linear Paul trap. A 9Be+ ion 2 MHz harmonic well located one zone was laser-cooled to near its ground state motion transported 370 micrometers by moving another zone. This accomplished 8 microseconds, corresponding 16 periods oscillation. Starting from with n=0.1 quanta, excited displaced coherent n=1.6 quanta but on completion returned close...

As experimental platforms for quantum information processing continue to mature, characterization of the quality unitary gates that can be applied their bits (qubits) becomes essential. Eventually, must sufficiently high support arbitrarily long computations. Randomized benchmarking already provides a platform-independent method assessing one-qubit rotations. Here we describe an extension this multi-qubit gates. We provide protocol evaluating performance Clifford unitaries, which form basis...

Teleporting a trapped-ion quantum gate Gating—controlling the state of one qubit conditioned on another—is key procedure in all information processors. As scale processors increases, qubits will need to interact over larger and distances, which presents an experimental challenge solid-state architectures. Wan et al. implemented 20-year-old theoretical proposal teleportation that allows separated effectively. They deterministically teleported controlled-NOT between two computational spatially...

Encoding logical qubits in bosonic modes provides a potentially hardware-efficient implementation of fault-tolerant quantum information processing. Here, we demonstrate high-fidelity and deterministic preparation highly nonclassical states the mechanical motion trapped ion. Our approach implements error-suppressing pulses through optimized dynamical modulation laser-driven spin-motion interactions to generate target state single step. We fidelities for Gottesman-Kitaev-Preskill as high...

We use electromagnetically-induced-transparency laser cooling to cool motional modes of a linear ion chain. As demonstration, we apply on 24Mg+ ions the axial 9Be+-24Mg+ pair and 9Be+-24Mg+-24Mg+-9Be+ chain, thereby sympathetically 9Be+ ions. Compared previous implementations conventional Raman sideband cooling, achieve approximately an order-of-magnitude reduction in duration required near ground state significant intensity.

We demonstrate a trapped-ion entangling-gate scheme proposed by Bermudez et al. [Phys. Rev. A 85, 040302 (2012)]. Simultaneous excitation of strong carrier and single-sideband transition enables deterministic creation entangled states. The method works for magnetic field-insensitive states, is robust against thermal excitations, includes dynamical decoupling from qubit dephasing errors, provides simplifications in experimental implementation compared to some other entangling gates with...

The accuracy of state-of-the-art atomic clocks is derived from the insensitivity narrow optical resonances to environmental perturbations. Two such in singly ionized lutetium have been identified with potentially lower sensitivities compared other clock candidates. Here we report measurement most significant unknown property both transitions, static differential scalar polarizability. From this, fractional blackbody radiation shift for one transitions found be -1.36(9) × 10-18 at 300 K,...

Analog quantum computers can calculate molecular vibronic spectra using time-domain simulation, with exponentially greater scalability than previous, frequency-domain approaches. An accurate, trapped-ion simulation of SO 2 validates the approach.

Identifying and calibrating quantitative dynamical models for physical quantum systems is important a variety of applications. Here we present closed-loop Bayesian learning algorithm estimating multiple unknown parameters in model, using optimized experimental ``probe'' controls measurement. The estimation based on particle filter, designed to autonomously choose informationally probe experiments with which compare model predictions. We demonstrate the performance both simulated calibration...

Abstract We propose a protocol for the preparation of generalized Greenberger–Horne–Zeilinger (GHZ) states N atoms each with d = 3 or 4 internal levels. generalize celebrated one-axis twisting (OAT) Hamiltonian qubits to qudits by including OAT interactions equal strengths between every pair qudit levels, we call as balanced (BOAT). Analogous qubits, find that starting from product state an arbitrary number , dynamics under BOAT leads formation GHZ qutrits ( 3) and ququarts 4). While could...

We apply laser fields to trapped atomic ions constrain the quantum dynamics from a simultaneously applied global microwave field an initial product state and target entangled state. This approach comes under what has become known in literature as "quantum Zeno dynamics" we use it prepare states of two three ions. With ^{9}Be^{+} ions, obtain Bell fidelities up 0.990_{-5}^{+2}; with W-state fidelity 0.910_{-7}^{+4} is obtained. Compared other methods producing entanglement this procedure can...

We examine a range of effects arising from ac magnetic fields in high-precision metrology. These results are directly relevant to measurements and accuracy assessments for state-of-the-art optical clocks. Strategies characterize these discussed simple technique accurately determine trap-induced linear Paul trap is demonstrated by using $^{171}\mathrm{Yb}^{+}$.

We demonstrate precision measurement and control of inhomogeneous broadening in a multi-ion clock consisting three $^{176}{\mathrm{Lu}}^{+}$ ions. Microwave spectroscopy between hyperfine states the $^{3}{D}_{1}$ level is used to characterize differential systematic shifts ions, most notably those associated with electric quadrupole moment. By appropriate alignment magnetic field, we suppression these effects $\ensuremath{\sim}{10}^{\ensuremath{-}17}$ relative...

We report correlation measurements on two ^{9}Be^{+} ions that violate a chained Bell inequality obeyed by any local-realistic theory. The correlations can be modeled as derived from mixture of probabilistic distribution and violates the inequality. A statistical framework is formulated to quantify fraction allowable in observed without fair-sampling or independent-and-identical-distributions assumptions. exclude models our experiment whose above 0.327 at 95% confidence level. This bound...

Measurement of the ^{138}Ba^{+} ^{2}S_{1/2}-^{2}D_{5/2} clock transition frequency and D_{5/2} Landé g_{J} factor are reported. The ν_{Ba^{+}}=170126432449333.31±(0.39)_{stat}±(0.29)_{sys} Hz, is obtained with accuracy limited by calibration maser used as a reference oscillator. for ^{2}D_{5/2} level determined to be g_{D}=1.20036739(24), which 30-fold improvement on previous measurements. g-factor measurements corrected an ac-magnetic field from trap-drive-induced currents in electrodes,...

We propose and experimentally demonstrate a scheme that realizes hyperfine averaging during Ramsey interrogation of clock transition. The method eliminates the need to average over multiple optical transitions, reduces sensitivity its environment, inhomogeneous broadening in multi-ion clock. is compatible with autobalanced spectroscopy, which facilitates elimination residual shifts due imperfect implementation ac stark from probe. using correlation spectroscopy...

Qubits encoded in hyperfine states of trapped ions are ideal for quantum computation given their long lifetimes and low sensitivity to magnetic fields, yet they suffer from off-resonant scattering during detection, often limiting measurement fidelity. In ${}^{171}{\text{Yb}}^{+}$ this is exacerbated by a fluorescence yield, which leads need complex expensive hardware, problematic bottleneck especially when scaling up the number qubits. We demonstrate detection routine based on electron...

Measurement of the branching ratios for $6P_{1/2}$ decays to $6S_{1/2}$ and $5D_{3/2}$ in $^{138}$Ba$^+$ are reported with decay probability from measured be $p=0.268177\pm(37)_\mathrm{stat}-(20)_\mathrm{sys}$. This result differs a recent report by $12\sigma$. A detailed account systematics is given likely source discrepancy identified. The new value ratio combined previous experimental results give estimate $\tau=7.855(10)\,\mathrm{ns}$ lifetime. In addition, matrix elements calculated...

We perform high resolution spectroscopy on $^{176}$Lu$^+$ including the $^1S_0\leftrightarrow{^3}D_1$ and $^1S_0\leftrightarrow{^3}D_2$ clock transitions. Hyperfine structures optical frequencies relative to $^1S_0$ ground state of four low lying excited states are given a few tens kHz resolution. This covers most relevant transitions involved in operation with this isotope. Additionally, measurements $^3D_2$ hyperfine structure may provide access higher order nuclear moments, specifically...

We report measurements of the branching fraction, hyperfine constant, and second-order Zeeman coefficient D$_{5/2}$ level in $^{171}$Yb$^+$ with up to two orders-of-magnitude improvement precision compared previously reported values. estimate electric quadrupole reduced matrix element S$_{1/2}$ $\leftrightarrow$ transition be 12.5(4) $e a_0^2$. Furthermore, we determine frequency F$_{7/2}$ $^{1}$D$[3/2]_{3/2}$ at 760 nm a $\sim$25-fold precision. These provide benchmarks for...