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Quantifying quantum mechanical uncertainty is vital for the increasing number of experiments that reach the uncertainty limited regime. We present a method for computing tight variance uncertainty relations, i.e., the optimal…

Quantum Physics · Physics 2017-11-01 René Schwonnek , Lars Dammeier , Reinhard F. Werner

Quantum sensors are expected to be a prominent use-case of quantum technologies, but in practice, noise easily degrades their performance. Quantum sensors can for instance be afflicted with erasure errors. Here, we consider using quantum…

Information Theory · Computer Science 2023-03-23 Yingkai Ouyang , Narayanan Rengaswamy

Gentle measurements of quantum states do not entirely collapse the initial state. Instead, they provide a post-measurement state at a prescribed trace distance $\alpha$ from the initial state together with a random variable used for quantum…

Quantum Physics · Physics 2026-05-28 Cristina Butucea , Jan Johannes , Henning Stein

Experimentally achieving the precision that standard quantum metrology schemes promise is always challenging. Recently, additional controls were applied to design feasible quantum metrology schemes. However, these approaches generally does…

Quantum Physics · Physics 2020-07-22 Xiaodong Yang , Jayne Thompson , Ze Wu , Mile Gu , Xinhua Peng , Jiangfeng Du

Quantum metrology aims to exploit many-body quantum states to achieve parameter-estimation precision beyond the standard quantum limit. For unitary parameter encoding generated by local Hamiltonians, such enhancement is characterized by…

Quantum Physics · Physics 2025-12-24 Junjie Chen , Rui Luo , Yuxuan Yan , You Zhou , Xiongfeng Ma

Robust quantum control can achieve noise-resilience of quantum systems and quantum technological devices. While the need for noise-resilience grows with the number of fluctuating quantities, and thus typically with the number of qubits,…

The presence of noise in quantum computers hinders their effective operation. Even though quantum error correction can theoretically remedy this problem, its practical realization is still a challenge. Testing and benchmarking noisy,…

Quantum Physics · Physics 2023-02-15 Adrian Ortega , Orsolya Kálmán , Tamás Kiss

Permitting a more precise measurement to physical quantities than the classical limit by using quantum resources, quantum metrology holds a promise in developing many revolutionary technologies. However, the noise-induced decoherence forces…

Quantum Physics · Physics 2023-08-03 Si-Yuan Bai , Jun-Hong An

Small, controllable quantum systems, known as quantum probes, have been proposed to estimate various parameters characterizing complex systems such as the environments of quantum systems. These probes, prepared in some initial state, are…

Quantum Physics · Physics 2021-07-21 Hamza Ather , Adam Zaman Chaudhry

We investigate all possible noise environments for controlled remote state preparation. We find that the optimal efficiency is not only dependent on the isolate decay rate but also dependent on the coupling term of environments. Such a…

Quantum Physics · Physics 2016-04-06 Yuan-hua Li , Zisheng Wang , Hua-qing Zhou , Xian-feng Chen

We study the dynamics of quantum dissension for three qubit states in various dissipative channels such as amplitude damping, dephasing and depolarizing. Our study is solely based on Markovian environments where quantum channels are without…

Quantum Physics · Physics 2014-12-01 Pratik K. Sarangi , Indranil Chakrabarty

The effectiveness of measurement-based feedback control (MBFC) protocols is hampered by the presence of measurement noise, which affects the ability to accurately infer the underlying dynamics of a quantum system from noisy continuous…

Quantum Physics · Physics 2023-11-23 Sangkha Borah , Bijita Sarma

We consider an arbitrary qubit channel depending on a single parameter, which is to be estimated by a physical process. Using the quantum Fisher information per channel invocation to quantify the estimation accuracy, we consider various…

Quantum Physics · Physics 2019-02-06 David Collins

Variational quantum dynamics simulations (VQDS) provide a promising route to simulate real- and imaginary-time quantum dynamics on noisy intermediate-scale quantum devices using fixed-depth circuits. However, their practical performance is…

Quantum Physics · Physics 2026-05-21 Feng Zhang , Niladri Gomes , Joshua Aftergood , Thomas Iadecola , Yong-Xin Yao , Peter P. Orth

Arrays of atoms trapped in optical tweezers combine features of programmable analog quantum simulators with atomic quantum sensors. Here we propose variational quantum algorithms, tailored for tweezer arrays as programmable quantum sensors,…

Complete characterization of a noisy multipartite quantum state in terms of entanglement requires full knowledge of how the entanglement content in the state is affected by the spatial distribution of noise in the state. Specifically, we…

Quantum Physics · Physics 2020-03-05 Ratul Banerjee , Amit Kumar Pal , Aditi Sen De

Information and correlations in a quantum system are closely related through the process of measurement. We explore such relation in a many-body quantum setting, effectively bridging between quantum metrology and condensed matter physics.…

Quantum Physics · Physics 2012-06-20 Luigi Amico , Davide Rossini , Alioscia Hamma , Vladimir E. Korepin

We study the precise phase estimation using squeezed states with photon losses present. Our exact quantum Fisher information calculation shows significant quantum enhancement and thus reveals the benchmark for practical quantum metrology in…

Quantum Physics · Physics 2013-08-13 Xiao-Xiao Zhang , Yu-Xiang Yang , Xiang-Bin Wang

In recent years the paradigm based on entanglement as the unique measure of quantum correlations has been challenged by the rise of new correlation concepts, such as quantum discord, able to reveal quantum correlations that are present in…

Quantum Physics · Physics 2013-05-30 Paolo Giorda , Michele Allegra , Matteo G. A. Paris

Quantum metrology promises high-precision measurements of classical parameters with far reaching implications for science and technology. So far, research has concentrated almost exclusively on quantum-enhancements in integrable systems,…

Quantum Physics · Physics 2018-04-16 Lukas J. Fiderer , Daniel Braun