Numeric Optimization for Configurable, Parallel, Error‐Robust Entangling Gates in Large Ion Registers

  title={Numeric Optimization for Configurable, Parallel, Error‐Robust Entangling Gates in Large Ion Registers},
  author={Christopher D. B. Bentley and Harrison Ball and Michael J. Biercuk and Andr'e R. R. Carvalho and Michael R. Hush and Harry J. Slatyer},
  journal={Advanced Quantum Technologies},
A class of entangling gates for trapped atomic ions is studied and the use of numeric optimization techniques to create a wide range of fast, error‐robust gate constructions is demonstrated. A numeric optimization framework is introduced targeting maximally‐ and partially‐entangling operations on ion pairs, multi‐ion registers, multi‐ion subsets of large registers, and parallel operations within a single register. Ions are assumed to be individually addressed, permitting optimization over… 
Numerical Engineering of Robust Adiabatic Operations
Adiabatic operations are powerful tools for robust quantum control in numerous fields of physics, chemistry and quantum information science. The inherent robustness due to adiabaticity can, however,
Programming the full stack of an open-access quantum computer
This work presents a new quantum programming language called ‘Quala’ that enables true full-stack programming of quantum hardware and intends for this language to bridge the gap between circuit-level programming and physical operations on real hardware while maintaining full transparency in each level of the stack.
Software tools for quantum control: improving quantum computer performance through noise and error suppression
This manuscript introduces software tools for the application and integration of quantum control in quantum computing research, serving the needs of hardware R&D teams, algorithm developers, and end users, and describes a software architecture leveraging both high-performance distributed cloud computation and local custom integration into hardware systems.
Batch Optimization of Frequency-Modulated Pulses for Robust Two-Qubit Gates in Ion Chains
Mingyu Kang, 2, ∗ Qiyao Liang, 2 Bichen Zhang, 3, † Shilin Huang, 3 Ye Wang, 3 Chao Fang, 3 Jungsang Kim, 2, 3, 4 and Kenneth R. Brown 2, 3, 5, ‡ Duke Quantum Center, Duke University, Durham, North
Designing Filter Functions of Frequency-Modulated Pulses for High-Fidelity Two-Qubit Gates in Ion Chains
Mingyu Kang, 2, ∗ Ye Wang, 3, † Chao Fang, 3 Bichen Zhang, 3 Omid Khosravani, 3 Jungsang Kim, 2, 3, 4 and Kenneth R. Brown 2, 3, 5, ‡ Duke Quantum Center, Duke University, Durham, NC 27701, USA
Quantum control methods for robust entanglement of trapped ions
A major obstacle in the way of practical quantum computing is achieving scalable and robust high-fidelity entangling gates. To this end, quantum control has become an essential tool, as it can make
Quantum optimal control in quantum technologies. Strategic report on current status, visions and goals for research in Europe
Quantum optimal control, a toolbox for devising and implementing the shapes of external fields that accomplish given tasks in the operation of a quantum device in the best way possible, has evolved
More speed out of the quantum gate
Quantum gates on trapped ions may be quicker and more reliable owing to squeezing of their vibrational motion. A threefold drop in operation time shows potential for applications in quantum
Robust entanglement by continuous dynamical decoupling of the J-coupling interaction
We propose a σ z ⊗ σ z laser-free entangling gate which uses the intrinsic J-coupling of ions in a static magnetic gradient. Dephasing of the interaction is suppressed by means of continuous
Scalable hyperfine qubit state detection via electron shelving in the 2D5/2 and 2F7/2 manifolds in 171Yb+
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


Phase-Modulated Entangling Gates Robust to Static and Time-Varying Errors
Entangling operations are among the most important primitive gates employed in quantum computing and it is crucial to ensure high-fidelity implementations as systems are scaled up. We experimentally
Parallel entangling operations on a universal ion-trap quantum computer
Parallel two-qubit entangling gates are realized in an array of fully connected trapped-ion qubits, achieving a full-adder operation on a quantum processor with an average fidelity of 83.3 per cent.
Theory of robust multiqubit nonadiabatic gates for trapped ions
The prevalent approach to executing quantum algorithms on quantum computers is to break-down the algorithms to a concatenation of universal gates, typically single and two-qubit gates. However such a
Global entangling gates on arbitrary ion qubits
This work proposes and implements a scalable scheme for realizing global entangling gates on multiple 171Yb+ ion qubits by coupling to multiple motional modes through modulated laser fields and develops a system with fully independent control capability on each ion.
Trapped ion scaling with pulsed fast gates
Fast entangling gates for trapped ions offer vastly improved gate operation times relative to implemented gates, as well as approaches to trap scaling. Gates on neighbouring ions only involve local
Phase-modulated decoupling and error suppression in qubit-oscillator systems.
It is demonstrated how the exclusive use of discrete shifts in the phase of the field moderating the qubit-oscillator interaction is sufficient to both ensure multiple oscillator modes are decoupled and to suppress the effects of fluctuations in the driving field.
Resilient Entangling Gates for Trapped Ions.
This work experimentally demonstrates how a new type of Mølmer-Sørensen gate protects against infidelity caused by heating of the motional mode used during the gate, and shows how the same technique simultaneously provides significant protection against slow fluctuations and mis-sets in the secular frequency.
Fast quantum logic gates with trapped-ion qubits
This work demonstrates entanglement generation for gate times as short as 480 nanoseconds—less than a single oscillation period of an ion in the trap and eight orders of magnitude shorter than the memory coherence time measured in similar calcium-43 hyperfine qubits.
Robust 2-Qubit Gates in a Linear Ion Crystal Using a Frequency-Modulated Driving Force.
An optimized frequency-modulated 2-qubit gate that can suppress errors to less than 0.01% and is robust against frequency drifts over ±1  kHz is obtained.
Experimental comparison of two quantum computing architectures
It is shown that quantum algorithms and circuits that use more connectivity clearly benefit from a better-connected system of qubits, and suggested that codesigning particular quantum applications with the hardware itself will be paramount in successfully using quantum computers in the future.