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We establish a quantum functional central limit for the dynamics of a system coupled to a Fermionic bath with a general interaction linear in the creation, annihilation and scattering of the bath reservoir. Following a quantum Markovian…

Quantum Physics · Physics 2007-05-23 John Gough , Andrei Sobolev

A Markovian model for a quantum automata, i.e. an open quantum dynamical discrete-time system with input and output channels and a feedback, is described. A dynamical theory of quantum discrete-time adaptive measurements and multi-stage…

Quantum Physics · Physics 2007-05-23 V. P. Belavkin

The analysis of charge noise based on the Bloch-Redfield treatment of an ensemble of dissipative two-level fluctuators generally results in a violation of the fluctuation-dissipation theorem. The standard Markov approximation (when applied…

Quantum Physics · Physics 2021-01-19 Xinyuan You , Aashish A. Clerk , Jens Koch

High-fidelity two-qubit gates in quantum computers are often hampered by fluctuating experimental parameters. The effects of time-varying parameter fluctuations lead to coherent noise on the qubits, which can be suppressed by designing…

Quantum Physics · Physics 2023-01-06 Mingyu Kang , Ye Wang , Chao Fang , Bichen Zhang , Omid Khosravani , Jungsang Kim , Kenneth R. Brown

We derive a universal bound on the efficiency with which "dissipated" work can generate distinguishable changes in a quantum many-body state at a finite temperature, as quantified by the quantum Fisher information. The bound follows solely…

Strongly Correlated Electrons · Physics 2026-02-06 Debanjan Chowdhury

Quantum impurities are ubiquitous in condensed matter physics and constitute the most stripped-down realization of many-body problems. While measuring their finite-frequency response could give access to key characteristics such as…

We study bounds on ratios of fluctuations in steady-state time-reversal heat engines controlled by multi affinities. In the linear response regime, we prove that the relative fluctuations (precision) of the output current (power) is always…

Statistical Mechanics · Physics 2021-11-17 Sushant Saryal , Matthew Gerry , Ilia Khait , Dvira Segal , Bijay Kumar Agarwalla

Continuous monitoring of open quantum-optical systems offers a promising route towards quantum-enhanced estimation precision. In such continuous-measurement-based sensing protocols, the ultimate precision limit is dictated, through the…

Quantum Physics · Physics 2025-12-01 Cheng Zhang , Mauro Cirio , Xin-Qi Li , Pengfei Liang

We develop a general perturbative computation of finite-frequency quantum noise which applies, in particular, to both good or weakly transmitting strongly correlated conductors coupled to a generic environment. Under a minimal set of…

Mesoscale and Nanoscale Physics · Physics 2016-01-20 Benjamin Roussel , Pascal Degiovanni , Inès Safi

The efficient sensing of weak environmental perturbations via special degeneracies called exceptional points in non-Hermitian systems has gained enormous traction in the last few decades. However, in contrast to the extensive literature on…

Quantum Physics · Physics 2022-03-02 J. Wang , D. Mukhopadhyay , G. S. Agarwal

Feedback control is a renowned mechanism for attenuating intrinsic fluctuation in regulatory networks. However, its impact on the response sensitivity to external signals and the response timescale, which are also critical for signal…

Biological Physics · Physics 2024-10-17 Ka Kit Kong , Feng Liu

Fluctuations are intrinsic to microscopic systems and impose fundamental limits on nonequilibrium precision, as captured by the thermodynamic uncertainty relation (TUR), which links current fluctuations to entropy production. While feedback…

Quantum Physics · Physics 2026-02-27 Ryotaro Honma , Tan Van Vu

Quantum noise suppression and phase-sensitive modulation of continuously variable in vacuum and squeezed fields in a hybrid resonant cavity system are investigated theoretically. Multiple dark windows similar to electromagnetic induction…

Quantum Physics · Physics 2023-08-09 Ke Di , Shuai Tan , Liyong Wang , Anyu Cheng , Xi Wang , Yuming Sun , Junqi Guo , Yu Liu , Jiajia Du

Quantum metrology promises precision beyond classical limits, yet environmental noise typically degrades the quantum resources required for such enhancement. In this work, we investigate frequency estimation in noisy continuous-variable…

Quantum Physics · Physics 2026-05-08 Ayan Patra , Manju , Aditi Sen De , Matteo G. A. Paris

Detection of radiation signals is at the heart of precision metrology and sensing. In this article we show how the fluctuations in photon counting signals can be exploited to optimally extract information about the physical parameters that…

Quantum Physics · Physics 2014-05-13 Alexander Holm Kiilerich , Klaus Mølmer

We examine metrological scenarios where the parameter of interest is encoded onto a quantum state through the action of a noisy quantum gate and investigate the ultimate bound to precision by analyzing the behaviour of the Quantum Fisher…

Quantum Physics · Physics 2025-02-18 Giovanni Ragazzi , Simone Cavazzoni , Paolo Bordone , Matteo G. A. Paris

In quantum multi-parameter estimation, the precision of estimating unknown parameters is bounded by the Cramer-Rao bound (CRB), defined via the inverse of the Fisher information matrix (FIM). However, in certain scenarios such as…

Quantum Physics · Physics 2025-11-18 Min Namkung , Changhyoup Lee , Hyang-Tag Lim

We consider the unitary time evolution of continuous quantum mechanical systems confined to a cavity in contact with a finite bath of variable size. Measures for Markovianity for such finite system-bath configurations are developed in terms…

Light scattering from resonantly or nearly resonantly excited systems, known as resonance fluorescence, has been gaining importance as a versatile tool for investigating quantum states of matter and readout of quantum information, recently…

Quantum Physics · Physics 2023-10-02 Rafał A. Bogaczewicz , Paweł Machnikowski

With the advent of quantum technology, the interest in communication tasks assisted by quantum systems has increased both in academia and industry. Nonetheless, the transmission of a quantum state in real-world scenarios is bounded by…