English
Related papers

Related papers: Variational Quantum Metrology with Loschmidt Echo

200 papers

The number of times that we can access a system to extract information via quantum metrology is always finite, and possibly small, and realistic amounts of prior knowledge tend to be moderate. Thus theoretical consistency demands a…

Quantum Physics · Physics 2021-12-02 Jesús Rubio

The laws of quantum mechanics allow to perform measurements whose precision supersedes results predicted by classical parameter estimation theory. That is, the precision bound imposed by the central limit theorem in the estimation of a…

Quantum effects like entanglement and coherent amplification can be used to drastically enhance the accuracy of quantum parameter estimation beyond classical limits. However, challenges such as decoherence and time-dependent errors hinder…

Quantum Physics · Physics 2025-02-18 Yulong Dong , Jonathan A. Gross , Murphy Yuezhen Niu

The state-of-the-art machine learning approaches are based on classical von Neumann computing architectures and have been widely used in many industrial and academic domains. With the recent development of quantum computing, researchers and…

Machine Learning · Computer Science 2020-07-21 Samuel Yen-Chi Chen , Chao-Han Huck Yang , Jun Qi , Pin-Yu Chen , Xiaoli Ma , Hsi-Sheng Goan

We propose a variational quantum classifier operating on high dimensional deep representations via amplitude encoding, stabilized by a learnable classical pre encoding layer.By combining normalized amplitude embeddings with bounded quantum…

Machine Learning · Computer Science 2026-05-18 Ying Chen , Paolo Giudici , Vasily Kolesnikov , Paolo Recchia

It is challenging to construct metrology schemes which harness quantum features such as entanglement and coherence to surpass the standard quantum limit. We propose an ansatz for devising adaptive-feedback quantum metrology (AFQM) strategy…

Quantum Physics · Physics 2020-02-19 Yi Peng , Heng Fan

Today's experimental noisy quantum processors can compete with and surpass all known algorithms on state-of-the-art supercomputers for the computational benchmark task of Random Circuit Sampling [1-5]. Additionally, a circuit-based quantum…

Quantum Physics · Physics 2024-01-22 K. Kechedzhi , S. V. Isakov , S. Mandrà , B. Villalonga , X. Mi , S. Boixo , V. Smelyanskiy

The impressive progress in quantum hardware in the last years has raised the interest of the quantum computing community in harvesting the computational power of such devices. However, in the absence of error correction, these devices can…

Quantum Physics · Physics 2023-02-21 Giacomo De Palma , Milad Marvian , Cambyse Rouzé , Daniel Stilck França

We derive a new variational principle for the quantum Fisher information leading to a simple iterative alternating algorithm, the convergence of which is proved. The case of a fixed measurement, i.e. the classical Fisher information, is…

Quantum Physics · Physics 2013-12-06 Katarzyna Macieszczak

Variational quantum algorithms have emerged as a cornerstone of contemporary quantum algorithms research. Practical implementations of these algorithms, despite offering certain levels of robustness against systematic errors, show a decline…

A central feature of quantum metrology is the possibility of Heisenberg scaling, a quadratic improvement over the limits of classical statistics. This scaling, however, is notoriously fragile to noise. While for some noise types it can be…

Quantum Physics · Physics 2022-06-08 Giulio Chiribella , Xiaobin Zhao

Anharmonic potential quantum system play crucial role in physics as they provide a more realistic description of oscillatory phenomena, which often deviate from the idealized harmonic model. However, simulating such system on classical…

Quantum Physics · Physics 2025-10-08 Saurav Suman , Bikash K. Behera , Vivek Vyas , Prasanta k. Panigrahi

Quantum mechanics allows measurements that surpass the fundamental sensitivity limits of classical methods. To benefit from the quantum advantage in a practical setting, the receiver should use communication channels resources optimally;…

Quantum Physics · Physics 2018-02-26 I. A. Burenkov , O. V. Tikhonova , S. V. Polyakov

We investigate the sensing capacity of non-equilibrium dynamics in quantum systems exhibiting Bloch oscillations. By focusing on the resource efficiency of the probe, quantified by quantum Fisher information, we find different scaling…

Quantum Physics · Physics 2025-07-16 Hassan Manshouri , Moslem Zarei , Mehdi Abdi , Sougato Bose , Abolfazl Bayat

We consider highly inaccurate measurements made on classical stochastic and quantum systems. In the quantum case such a \e{weak} measurement preserves coherence between the system's alternatives. We demonstrate that in both cases the…

Quantum Physics · Physics 2026-03-16 D. Sokolovski , D. Alonso , S. Brouard

Quantum sensing exploits non-classical effects to overcome limitations of classical sensors, with applications ranging from gravitational-wave detection to nanoscale imaging. However, practical quantum sensors built on noisy…

Quantum Physics · Physics 2025-05-30 Ivana Nikoloska , Hamdi Joudeh , Ruud van Sloun , Osvaldo Simeone

While quantum metrology enables measurement precision beyond classical limits, its performance is often susceptible to experimental imperfections. Most prior studies have focused on imperfections in quantum states and operations. Here, we…

Quantum Physics · Physics 2026-05-05 Byeong-Yoon Go , Geunhee Gwak , Young-Do Yoon , Sungho Lee , Nicolas Treps , Jiyong Park , Young-Sik Ra

Quantum Metrology calculates the ultimate precision of all estimation strategies, measuring what is their root mean-square error (RMSE) and their Fisher information. Here, instead, we ask how many bits of the parameter we can recover,…

Quantum Physics · Physics 2017-11-22 Lorenzo Maccone , Majid Hassani , Chiara Macchiavello

Quantum phase estimation is a paradigmatic problem in quantum sensing andmetrology. Here we show that adaptive methods based on classical machinelearning algorithms can be used to enhance the precision of quantum phase estimation when noisy…

Quantum Physics · Physics 2021-09-01 Nelson Filipe Costa , Yasser Omar , Aidar Sultanov , Gheorghe Sorin Paraoanu

A pivotal task in quantum metrology, and quantum parameter estimation in general, is to de- sign schemes that achieve the highest precision with given resources. Standard models of quantum metrology usually assume the dynamics is fixed, the…

Quantum Physics · Physics 2017-07-18 Jing Liu , Haidong Yuan