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We study the approximate state preparation problem on noisy intermediate-scale quantum (NISQ) computers by applying a genetic algorithm to generate quantum circuits for state preparation. The algorithm can account for the specific…

Quantum Physics · Physics 2023-05-10 Tom Rindell , Berat Yenilen , Niklas Halonen , Arttu Pönni , Ilkka Tittonen , Matti Raasakka

To achieve the practical applications of near-term noisy quantum devices, low-cost ways to mitigate the noise damages in the devices are essential. In many applications, the noiseless state we want to prepare is often a pure state, which…

Quantum Physics · Physics 2021-07-16 Zhenyu Cai

Quantum states that are symmetric under particle exchange play a crucial role in fields such as quantum metrology and quantum error correction. We use a variational circuit composed of global one-axis twisting and global rotations to…

Finding minimal time and establishing the structure of the corresponding optimal controls which can transfer a given initial state of a quantum system into a given target state is a key problem of quantum control. In this work, this problem…

Quantum Physics · Physics 2025-02-21 L. V. Lokutsievskiy , A. N. Pechen , M. I. Zelikin

Quantum speed limits provide ultimate bounds on the time required to transform one quantum state into another. Here, we extend the notion of quantum speed limits to collections of quantum states, investigating the time for converting a…

Quantum Physics · Physics 2024-04-10 Moein Naseri , Chiara Macchiavello , Dagmar Bruß , Paweł Horodecki , Alexander Streltsov

Perfect state transfer (PST) through a spin chain can be theoretically obtained via predesigned PST couplings. However, the corresponding experiment on IBM quantum computers demonstrates low transmission success probability (SP) due to…

Quantum Physics · Physics 2025-08-27 Zong-Yuan Ge , Lian-Ao Wu , Zhao-Ming Wang

Compared to general quantum states, the sparse states arise more frequently in the field of quantum computation. In this work, we consider the preparation for $n$-qubit sparse quantum states with $s$ non-zero amplitudes and propose two…

Quantum Physics · Physics 2024-04-10 Rui Mao , Guojing Tian , Xiaoming Sun

Ground-state preparation is an important task in quantum computation. The probabilistic imaginary-time evolution (PITE) method is a promising candidate for preparing the ground state of the Hamiltonian, which comprises a single ancilla…

Quantum Physics · Physics 2023-11-08 Hirofumi Nishi , Koki Hamada , Yusuke Nishiya , Taichi Kosugi , Yu-ichiro Matsushita

Evolution time of a qubit under a Hamiltonian operation is one of the key issues in quantum control, quantum information processing and quantum computing. It has a lower bound in Hermitian system, which is limited by the coupling between…

Atomic Physics · Physics 2022-06-03 Pengfei Lu , Teng liu , Yang Liu , Xinxin Rao , Qifeng Lao , Hao Wu , Feng Zhu , Le Luo

Quantum state preparation is a crucial process within numerous quantum algorithms, and the need for efficient initialization of quantum registers is ever increasing as demand for useful quantum computing grows. The problem arises as the…

Quantum Physics · Physics 2024-09-11 Andrew Wright , Marco Lewis , Paolo Zuliani , Sadegh Soudjani

We compare several quantum phase estimation (QPE) protocols intended for early fault-tolerant quantum computers (EFTQCs) in the context of models of their implementations on a surface code architecture. We estimate the logical and physical…

Quantum Physics · Physics 2024-03-04 Jacob S. Nelson , Andrew D. Baczewski

A key requirement to perform simulations of large quantum systems on near-term quantum hardware is the design of quantum algorithms with short circuit depth that finish within the available coherence time. A way to stay within the limits of…

Due to the exponential complexity of the resources required by quantum state tomography (QST), people are interested in approaches towards identifying quantum states which require less effort and time. In this paper, we provide a tailored…

Information Theory · Computer Science 2017-08-02 K. Li , J. Zhang , S. Cong

The variational quantum eigensolver is one of the most promising approaches for performing chemistry simulations using noisy intermediate-scale quantum (NISQ) processors. The efficiency of this algorithm depends crucially on the ability to…

The minimum evolution time between multi-qubit quantum states is estimated for non-Markovian quantum channels. We consider the maximally coherent pure and mixed states as well as multi-qubit $X$ states as initial states and discuss the…

Quantum Physics · Physics 2023-01-03 K. G. Paulson , Subhashish Banerjee

Superconducting qubit parameters drift on sub-second timescales, motivating calibration and benchmarking techniques that can be executed on millisecond timescales. We demonstrate an on-FPGA workflow that co-locates pulse generation, data…

We show that optimal control of the electron dynamics is able to prepare molecular ground states, within chemical accuracy, with evolution times approaching the bounds imposed by quantum mechanics. We propose a specific parameterization of…

Quantum Physics · Physics 2024-02-20 Davide Castaldo , Marta Rosa , Stefano Corni

A gate sequence of single-qubit transformations may be condensed into a single microwave pulse that maps a qubit from an initialized state directly into the desired state of the composite transformation. Here, machine learning is used to…

Quantum Physics · Physics 2025-07-18 Jaden Nola , Uriah Sanchez , Anusha Krishna Murthy , Elizabeth Behrman , James Steck

Isolated spins in semiconductors provide a promising platform to explore quantum mechanical coherence and develop engineered quantum systems. Silicon has attracted great interest as a host material for developing spin qubits because of its…

Mesoscale and Nanoscale Physics · Physics 2015-10-29 Dohun Kim , D. R. Ward , C. B. Simmons , D. E. Savage , M. G. Lagally , Mark Friesen , S. N. Coppersmith , Mark A. Eriksson

Coherence times for superconducting qubits have greatly improved over time. Moreover, small logical qubit architectures using engineered dissipation have shown great promise for further improvements in the coherence of a logical qubit…

Quantum Physics · Physics 2021-05-28 David Rodriguez Perez , Eliot Kapit