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In holonomic quantum computation, single-qubit gates are performed using driving protocols that trace out closed loops on the Bloch sphere, making them robust to certain pulse errors. However, dephasing noise that is transverse to the…

Quantum Physics · Physics 2021-09-01 Wenzheng Dong , Fei Zhuang , Sophia E. Economou , Edwin Barnes

A magnitude-least-squares radiofrequency pulse design algorithm is reported which uses interleaved exact and stochastically-generated inexact updates to escape local minima and find low-cost solutions. Inexact updates are performed using a…

Medical Physics · Physics 2024-07-23 Jonathan B. Martin , Charlotte R. Sappo , Benjamin M. Hardy , William A. Grissom

Single-qubit gates are in many quantum platforms applied using a linear drive resonant with the qubit transition frequency which is often theoretically described within the rotating-wave approximation (RWA). However, for fast gates on…

We study the suppression of noise-induced phase decoherence in a single atomic qubit by employing pulse sequences. The atomic qubit is composed of a single neutral atom in a far-detuned optical dipole trap and the phase decoherence may…

Quantum Physics · Physics 2015-05-13 Chih-Sung Chuu , Chuanwei Zhang

We consider a model of two interacting always-on, exchange-only qubits for which controlled phase ($CPHASE$), controlled NOT ($CNOT$), quantum Fourier transform ($QFT$) and $SWAP$ operations can be implemented only in a few electrical…

Mesoscale and Nanoscale Physics · Physics 2018-05-09 Jakub Łuczak , Bogdan R. Bułka

The benefit of exchange-only qubits compared to other spin qubit types is the universal control using only voltage controlled exchange interactions between neighboring spins. As a compromise, qubit operations have to be constructed from…

Superconducting qubits are one of the most advanced candidates to realize scalable and fault-tolerant quantum computing. Despite recent significant advancements in the qubit lifetimes, the origin of the loss mechanism for state-of-the-art…

Parametrized gate circuits are used in plentiful applications in the current NISQ era of quantum computing. These parametrized gates are chiefly implemented using analytically found pulse protocols, often yielding suboptimal gate times, and…

Quantum Physics · Physics 2025-04-10 Robert de Keijzer , Jurgen Snijders , André Carvalho , Servaas Kokkelmans

Considering the problem of the control of a two-state quantum system by an external field, we establish a general and versatile method that allows the derivation of smooth pulses, suitable for ultrafast applications, that feature the…

Quantum Physics · Physics 2015-06-15 D. Daems , A. Ruschhaupt , D. Sugny , S. Guerin

Long-time dynamical decoupling and quantum control of qubits require high-precision control pulses. Full characterization (quantum tomography) of imperfect pulses presents a bootstrap problem: tomography requires initial states of a qubit…

Quantum Physics · Physics 2015-05-18 V. V. Dobrovitski , G. de Lange , D. Ristè , R. Hanson

For superconducting quantum processors, stable high-fidelity two-qubit operations depend on precise flux control of the tunable coupler. However, the pulse distortion poses a significant challenge to the control precision. Current…

In trapped-ion quantum computers, two-qubit entangling gates are generated by applying spin-dependent force which uses phonons to mediate interaction between the internal states of the ions. To maintain high-fidelity two-qubit gates under…

Quantum Physics · Physics 2023-04-05 Zhubing Jia , Shilin Huang , Mingyu Kang , Ke Sun , Robert F. Spivey , Jungsang Kim , Kenneth R. Brown

Using a circuit QED device, we demonstrate a simple qubit measurement pulse shape that yields fast ring-up and ring-down of the readout resonator regardless of the qubit state. The pulse differs from a square pulse only by the inclusion of…

Quantum Physics · Physics 2016-02-03 D. T. McClure , Hanhee Paik , L. S. Bishop , M. Steffen , Jerry M. Chow , Jay M. Gambetta

Many techniques in quantum control rely on frequency separation as a means for suppressing unwanted couplings. In its simplest form, the mechanism relies on the low bandwidth of control pulses of long duration. Here we perform a…

Quantum Physics · Physics 2015-06-17 Felix Motzoi , Frank K. Wilhelm

We propose and validate on real quantum computing hardware a new method for extended two-qubit gate set design, replacing iterative, fine calibration with fast characterization of a small number of gate parameters which are then tracked and…

Unitary operations acting on a quantum system must be robust against systematic errors in control parameters for reliable quantum computing. Composite pulse technique in nuclear magnetic resonance (NMR) realises such a robust operation by…

Quantum Physics · Physics 2012-09-04 Tsubasa Ichikawa , Masamitsu Bando , Yasushi Kondo , Mikio Nakahara

Achieving high-fidelity control of quantum systems is essential for realization of a practical quantum computer. Composite pulse sequences which suppress different types of errors can be nested to suppress a wide variety of errors but the…

Mesoscale and Nanoscale Physics · Physics 2019-12-09 Utkan Güngördü , J. P. Kestner

In this paper, we introduce a neural network to generate optimal control pulses for general single-qubit quantum logic gates, within a Nuclear Magnetic Resonance (NMR) quantum computer. By utilizing a neural network, we can efficiently…

We consider the coherent control of a quantum bit by the use of short pulses with finite duration \tau_p. By shaping the pulse, we perturbatively decouple the dynamics of the bath from the dynamics of the quantum bit during the pulse. Such…

Quantum Physics · Physics 2012-02-09 Benedikt Fauseweh , Stefano Pasini , Götz S. Uhrig

Variational Quantum Algorithms (VQAs) have emerged as a powerful class of algorithms that is highly suitable for noisy quantum devices. Therefore, investigating their design has become key in quantum computing research. Previous works have…