The trapped-ion qubit tool box

Ozeri, Roee

doi:10.1080/00107514.2011.603578

Cited by 41 publications

(59 citation statements)

References 73 publications

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“…In this work, we show how one can abandon the far-detuned regime, while still preserving the nice properties of the driven single-sideband gate. Below, we show that by working in the context of the geometric phase gates [17,19,35], our driven nearly resonant single-sideband gate: (i) can attain speeds that are one order of magnitude faster than the far-detuned gate [8] for comparable parameters. For the specific parameters considered in this paper (see table 1) we can attain a gate speed of t g ∼ 63 µs.…”

Section: Drivenmentioning

confidence: 88%

Driven geometric phase gates with trapped ions

2013

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We describe a hybrid laser-microwave scheme to implement twoqubit geometric phase gates in crystals of trapped ions. The proposed gates can attain errors below the fault-tolerance threshold in the presence of thermal, dephasing, laser-phase and microwave-intensity noise. Moreover, our proposal is technically less demanding than previous schemes, since it does not require a laser arrangement with interferometric stability. The laser beams are tuned close to a single vibrational sideband to entangle the qubits, while strong microwave drivings provide the geometric character to the gate, and thus protect the qubits from these different sources of noise. A thorough analytic and numerical study of the performance of these gates in realistic noisy regimes is presented. A. Magnus expansion for the driven single-sideband Hamiltonian 28 Appendix B. Stochastic processes for the noise sources 31 References 372. Driven single-sideband geometric phase gates Two-ion crystals as the hardware for quantum logic gatesLet us start by describing the system under consideration: a two-ion (N = 2) crystal confined in a linear Paul trap [10]. Under certain conditions [11], such radio-frequency traps provide an effective quadratic confining potential, which is characterized by the so-called axial ω z , and radial {ω x , ω y } trap frequencies. Moreover, when {ω x , ω y } ω z , the ion equilibrium positions arrange in a string along the trap z-axis. As customary in these cases, when the particles only 2 During the completion of this work, we became aware of the results of [9]. In this work, the authors have also generalized the scheme described in [8] to the near-resonance regime where faster gates can be achieved. Moreover, they have presented an experimental realization of these ideas, showing that two-qubit gates with errors ε 2,q ≈ 2.6 × 10 −2 can be achieved using this hybrid laser-microwave scheme.

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Section: Drivenmentioning

confidence: 88%

Driven geometric phase gates with trapped ions

2013

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“…To perform error correction with the surface code, the required operations are single-qubit gates (H), two-qubit (gates controlled-NOT or CNOT), state initialization ( 0ñ | state), and measurement (Z-basis). Single-qubit gates are performed by the application of laser fields [36][37][38] or microwave radiation [39,40] to manipulate the hyperfine states of trapped 171 Yb + ( 2 S 1/2 F m 0; 0…”

Section: Mapping the Surface Code To An Ion Chainmentioning

confidence: 99%

“…We chose to study the surface code because the memory pseudothreshold, the error rate below which the encoded qubit outperforms the physical qubit, is superior to the 5-qubit code, the Steane code, and the Bare code, and comparable to the Bacon-Shor and twisted surface code [35].Atomic ions have proven to be high-fidelity qubits for quantum information processing. The internal states of the ions are controlled by the application of electromagnetic radiation with lasers [36][37][38] or microwaves [39,40]. Two-qubit gates are performed by conditionally exciting the coupled motion of ions in the chain dependent on the ionʼs internal states [41][42][43][44].…”

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confidence: 99%

Simulating the performance of a distance-3 surface code in a linear ion trap

Trout

Gutiérrez

et al. 2018

New J. Phys.

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We explore the feasibility of implementing a small surface code with 9 data qubits and 8 ancilla qubits, commonly referred to as surface-17, using a linear chain of 171 Yb+ ions. Two-qubit gates can be performed between any two ions in the chain with gate time increasing linearly with ion distance. Measurement of the ion state by fluorescence requires that the ancilla qubits be physically separated from the data qubits to avoid errors on the data due to scattered photons. We minimize the time required to measure one round of stabilizers by optimizing the mapping of the two-dimensional surface code to the linear chain of ions. We develop a physically motivated Pauli error model that allows for fast simulation and captures the key sources of noise in an ion trap quantum computer including gate imperfections and ion heating. Our simulations showed a consistent requirement of a two-qubit gate fidelity of 99.9% for the logical memory to have a better fidelity than physical two-qubit operations. Finally, we perform an analysis of the error subsets from the importance sampling method used to bound the logical error rates to gain insight into which error sources are particularly detrimental to error correction.

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“…If this frequency difference is tuned close to one of the normal mechanical modes of the crystal, the ODF can be made to excite collective vibrations of the ions. In general, a quantum harmonic oscillator driven offresonantly will traverse a closed loop in phase space with radius proportional to the driving force [19]. The system returns to its initial motional state at times τ = 2π/δ where δ is the detuning from resonance, acquiring a geometric phase proportional to the area of the loop.…”

Section: Global Unitary Operationsmentioning

confidence: 99%

Trapped-ion quantum error-correcting protocols using only global operations

et al. 2015

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Quantum error-correcting codes are many-body entangled states used to robustly store coherent quantum states over long periods of time in the presence of noise. Practical implementations will require efficient entangling protocols that minimise the introduction of noise during encoding or readout. We propose an experiment that uses only global operations to encode information to either the five-qubit repetition code or the five-qubit code on a two-dimensional ion Coulomb crystal architecture. We show we can prepare, read out, and acquire syndrome information for these two codes using only six and ten global entangling pulses respectively. We provide an error analysis, estimating we can achieve a six-fold improvement in coherence time with as much as 1% noise in the control parameters for each entangling operation.

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The trapped-ion qubit tool box

Cited by 41 publications

References 73 publications

Driven geometric phase gates with trapped ions

Driven geometric phase gates with trapped ions

Simulating the performance of a distance-3 surface code in a linear ion trap

Trapped-ion quantum error-correcting protocols using only global operations

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