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We develop a fidelity-informed neural pulse-compilation framework for a continuous family of single-qubit gates on a three-qubit liquid-state nuclear magnetic resonance (NMR) processor. Instead of decomposing each target unitary into a…

Quantum computers process information with the laws of quantum mechanics. Current quantum hardware is noisy, can only store information for a short time, and is limited to a few quantum bits, i.e., qubits, typically arranged in a planar…

Qubit noise spectroscopy is an important tool for the experimental investigation of open quantum systems. However, conventional techniques for noise spectroscopy are time-consuming, because they require measurements of the noise spectral…

Quantum Physics · Physics 2025-06-24 Kaixin Huang , Demitry Farfurnik , Alireza Seif , Mohammad Hafezi , Yi-Kai Liu

The optimization of robust quantum control is often tailored to specific tasks and suffers from inefficiencies due to the complexity of cost functions. Our recent findings indicate a highly effective methodology for the engineering of…

Quantum Physics · Physics 2025-01-10 Huiqi Xue , Xiu-Hao Deng

We present a genetic algorithm for finding a set of pulse sequences, or rotations, for a given quantum logic gate, as implemented by NMR. We demonstrate the utility of the method by showing that shorter sequences than have been previously…

Quantum Physics · Physics 2012-07-31 M. J. Rethinam , A. K. Javali , E. C. Behrman , J. E. Steck , S. R. Skinner

The ability of pulse-shaping devices to generate accurately quantum optimal control is a strong limitation to the development of quantum technologies. We propose and demonstrate a systematic procedure to design robust digital control…

Quantum Physics · Physics 2022-10-18 Meri Harutyunyan , Frederic Holweck , Dominique Sugny , Stephane Guerin

Experiments in coherent nuclear and electron magnetic resonance,and quantum computing in general correspond to control of quantum mechanical systems, guiding them from initial to final target states by unitary transformations. The control…

Quantum Physics · Physics 2015-06-17 Haidong Yuan , Daxiu Wei , Yajuan Zhang , Steffen Glaser , Navin Khaneja

Interconnecting clusters of qubits will be an essential element of scaling up future quantum computers. Operations between quantum processing units (QPUs) are usually significantly slower and costlier than those within a single QPU, so…

Quantum Physics · Physics 2022-09-09 Edwin Tham , Ilia Khait , Aharon Brodutch

Reducing the circuit depth of quantum circuits is a crucial bottleneck to enabling quantum technology. This depth is inversely proportional to the number of available quantum gates that have been synthesised. Moreover, quantum gate…

Quantum Physics · Physics 2022-12-15 Francesco Preti , Tommaso Calarco , Felix Motzoi

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

Quantum information processing (QIP) offers the promise of being able to do things that we cannot do with conventional technology. Here we present a new route for distributed optical QIP, based on generalized quantum non-demolition…

Quantum Physics · Physics 2009-11-11 W. J. Munro , Kae Nemoto , T. P. Spiller

We generalize the problem of the coherent control of small quantum systems to the case where the quantum bit (qubit) is subject to a fully general rotation. Following the ideas developed in Pasini et al (2008 Phys. Rev. A 77, 032315), the…

Quantum Physics · Physics 2008-07-09 S. Pasini , G. S. Uhrig

Reliable quantum information technologies depend on precise actuation and techniques to mitigate the effects of undesired disturbances such as environmental noise and imperfect calibration. In this work, we present a general framework based…

Quantum Physics · Physics 2024-09-20 Joshua Hanson , Dennis Lucarelli

Precise qubit manipulation is fundamental to quantum computing, yet experimental systems generally have stray coupling between the qubit and the environment, which hinders the necessary high-precision control. We report here the first…

Mesoscale and Nanoscale Physics · Physics 2013-04-04 Xin Wang , Lev S. Bishop , J. P. Kestner , Edwin Barnes , Kai Sun , S. Das Sarma

A clever choice and design of gate sets can reduce the depth of a quantum circuit, and can improve the quality of the solution one obtains from a quantum algorithm. This is especially important for near-term quantum computers that suffer…

Quantum Physics · Physics 2025-07-08 Madhav Mohan , Julius de Hond , Servaas Kokkelmans

In the era of Noisy Intermediate-Scale Quantum computing as well as in error correcting circuits, physical qubits coherence time and high fidelity gates are essential to the functioning of quantum computers. In this paper, we demonstrate…

Quantum Physics · Physics 2024-08-27 Max Cykiert , Eran Ginossar

Full connectivity of qubits is necessary for most quantum algorithms, which is difficult to directly implement on Noisy Intermediate-Scale Quantum processors. However, inserting swap gate to enable the two-qubit gates between uncoupled…

Quantum Physics · Physics 2021-02-03 Bin-Han Lu , Yu-Chun Wu , Wei-Cheng Kong , Qi Zhou , Guo-Ping Guo

The transmon, known for its fast operation time and the coherence time of tens of microseconds, is the most commonly used qubit for superconducting quantum processors. However, it is still necessary to enhance the coherence time and the…

Quantum Physics · Physics 2025-04-01 Jeongsoo Kang , Younghun Kwon

In the model of gate-based quantum computation, the qubits are controlled by a sequence of quantum gates. In superconducting qubit systems, these gates can be implemented by voltage pulses. The success of implementing a particular gate can…

Quantum Physics · Physics 2017-12-04 D. Willsch , M. Nocon , F. Jin , H. De Raedt , K. Michielsen

Systematic errors in spin rotation operations using simple RF pulses place severe limitations on the usefulness of the pulsed magnetic resonance methods in quantum computing applications. In particular, the fidelity of quantum logic…