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Related papers: Multi-level Quantum Noise Spectroscopy

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Hybrid Quantum Neural Networks (HQNNs) offer promising potential of quantum computing while retaining the flexibility of classical deep learning. However, the limitations of Noisy Intermediate-Scale Quantum (NISQ) devices introduce…

Quantum Physics · Physics 2025-05-07 Tasnim Ahmed , Alberto Marchisio , Muhammad Kashif , Muhammad Shafique

The topology of a pure state of two entangled photons is leveraged to provide a discretization of quantum information. Since discrete signals are inherently more resilient to the effects of perturbations, this discrete class of entanglement…

Quantum Physics · Physics 2024-11-01 Robert de Mello Koch , Bo-Qiang Lu , Pedro Ornelas , Isaac Nape , Andrew Forbes

Transmon qubits are a cornerstone of modern superconducting quantum computing platforms. Temporal fluctuations of energy relaxation in these qubits are widely attributed to microscopic two-level systems (TLSs) in device dielectrics and…

Excess noise is a major obstacle to high-performance continuous-variable quantum key distribution (CVQKD), which is mainly derived from the amplitude attenuation and phase fluctuation of quantum signals caused by channel instability. Here,…

Quantum Physics · Physics 2022-07-22 Kexin Liang , Geng Chai , Zhengwen Cao , Qing Wang , Lei Wang , Jinye Peng

The accumulation of quantum phase in response to a signal is the central mechanism of quantum sensing, as such, loss of phase information presents a fundamental limitation. For this reason approaches to extend quantum coherence in the…

Quantum computers are on the brink of surpassing the capabilities of even the most powerful classical computers. This naturally raises the question of how one can trust the results of a quantum computer when they cannot be compared to…

Detecting and quantifying quantum entanglement remain significant challenges in the noisy intermediate-scale quantum (NISQ) era. This study presents the implementation of quantum support vector machines (QSVMs) on IBM quantum devices to…

Quantum Physics · Physics 2025-04-10 M. Mahdian , Z. Mousavi

Noise in quantum information processing is often viewed as a disruptive and difficult-to-avoid feature, especially in near-term quantum technologies. However, noise has often played beneficial roles, from enhancing weak signals in…

Quantum Physics · Physics 2021-06-02 Yuxuan Du , Min-Hsiu Hsieh , Tongliang Liu , Dacheng Tao , Nana Liu

Quantum systems are inherently susceptible to noise -- a notorious factor that induces decoherence and limits the performance of quantum applications. To mitigate its detrimental effects, various techniques have been developed, including…

Quantum Physics · Physics 2025-05-21 Yu-Bo Hou , Xiaoan Ai , Ruizhe You , Changchun Zhong

Noise in contemporary quantum hardware is highly non-uniform across qubits and couplers, giving rise to localized low-noise "islands" within otherwise noisy device topologies. As quantum workloads scale, executions are increasingly forced…

Noisy, intermediate-scale quantum computers come with intrinsic limitations in terms of the number of qubits (circuit "width") and decoherence time (circuit "depth") they can have. Here, for the first time, we demonstrate a recently…

Quantum Physics · Physics 2020-09-02 Thomas Ayral , François-Marie Le Régent , Zain Saleem , Yuri Alexeev , Martin Suchara

Assessment of practical quantum information processing (QIP) remains partial without understanding limits imposed by noise. Unfortunately, mere description of noise grows exponentially with system size, becoming cumbersome even for modest…

Quantum Physics · Physics 2024-08-14 Vikesh Siddhu , John Smolin

Quantum spin fluctuations provide a unique way to study spin dynamics without system perturbation. Here we put forward an optical resonance shift spin noise spectroscopy as a powerful tool to measure the spin noise of various systems from…

Mesoscale and Nanoscale Physics · Physics 2020-07-01 D. S. Smirnov , K. V. Kavokin

One of the major challenges for erroneous quantum computers is undoubtedly the control over the effect of noise. Considering the rapid growth of available quantum resources that are not fully fault-tolerant, it is crucial to develop…

Quantum purity amplification (QPA) provides a novel approach to counteracting the pervasive noise that degrades quantum states. We present the optimal QPA protocol for general quantum systems and global noise, resolving a two-decade open…

Quantum Physics · Physics 2025-12-29 Zhaoyi Li , Honghao Fu , Takuya Isogawa , Caio Silva , Isaac Chuang

We investigate the effects of noise on parameterised quantum circuits using spectral analysis and classical signal processing tools. For different noise models, we quantify the additional, higher frequency modes in the output signal caused…

Quantum Physics · Physics 2022-11-11 Enrico Fontana , Ivan Rungger , Ross Duncan , Cristina Cîrstoiu

In this article, we explore the possibility of achieving noise suppression for finite-dimensional quantum systems through coherent feedback. For a quantum plant which is expected to evolve according to a target trajectory, noise effect…

Quantum Physics · Physics 2024-09-10 Shikun Zhang , Guofeng Zhang

As quantum devices scale toward practical machine learning applications, the binary qubit paradigm faces expressivity and resource efficiency limitations. Multi-level quantum systems, or qudits, offer a promising alternative by harnessing a…

Quantum Physics · Physics 2025-05-09 Tiago de Souza Farias , Lucas Friedrich , Jonas Maziero

Quantum sensors leverage nonclassical resources to achieve sensing precision at the Heisenberg limit, surpassing the standard quantum limit attainable through classical strategies. However, a critical issue is that the environmental noise…

Quantum Physics · Physics 2025-11-24 Hang Xu , Tailong Xiao , Jingzheng Huang , Jianping Fan , Guihua Zeng

Quantum noise is the key challenge in Noisy Intermediate-Scale Quantum (NISQ) computers. Previous work for mitigating noise has primarily focused on gate-level or pulse-level noise-adaptive compilation. However, limited research efforts…

Quantum Physics · Physics 2024-04-05 Hanrui Wang , Yongshan Ding , Jiaqi Gu , Zirui Li , Yujun Lin , David Z. Pan , Frederic T. Chong , Song Han