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Conventional priors used for signal recovery are often limited by the assumption that the type of a signal's variability, such as piecewise constant or linear behavior, is known and fixed. This assumption is problematic for complex signals…

Numerical Analysis · Mathematics 2025-10-24 Yao Xiao , Anne Gelb

We consider the problem of recursively and causally reconstructing time sequences of sparse signals (with unknown and time-varying sparsity patterns) from a limited number of noisy linear measurements. The sparsity pattern is assumed to…

Information Theory · Computer Science 2010-07-28 Namrata Vaswani

Probing signal injection is a well-established technique to extract additional information from a weakly (or non) observable dynamical system. Using averaging theory, a framework to analyse such schemes for general nonlinear systems has…

Systems and Control · Computer Science 2019-11-20 Bowen Yi , Romeo Ortega , Houria Siguerdidjane , Juan E. Machado , Weidong Zhang

We propose a method to measure time-reversal symmetry violation in molecules that overcomes the standard quantum limit while leveraging decoherence-free subspaces to mitigate sensitivity to classical noise. The protocol does not require an…

Atomic Physics · Physics 2024-01-25 Chi Zhang , Phelan Yu , Arian Jadbabaie , Nicholas R. Hutzler

In this paper we perform an exact study of ``Quantum Fidelity'' (also called Loschmidt Echo) for the time-periodic quantum Harmonic Oscillator of Hamiltonian : $$ \hat H\_{g}(t):=\frac{P^2}{2}+ f(t)\frac{Q^2}{2}+\frac{g^2}{Q^2} $$ when…

Mathematical Physics · Physics 2007-05-23 M. Combescure

Quantum noise sets a fundamental limit to the sensitivity of high-precision measurements. Suppressing it can be achieved by using non-classical states and quantum filters, which modify both the noise and signal response. We find a novel…

Quantum Physics · Physics 2021-03-09 Joe Bentley , Hendra Nurdin , Yanbei Chen , Haixing Miao

In time reversal acoustics experiments, a signal is emitted from a localized source, recorded at an array of receivers-transducers, time reversed, and finally re-emitted into the medium. A celebrated feature of time reversal experiments is…

Chaotic Dynamics · Physics 2007-05-23 Guillaume Bal , Leonid Ryzhik

We study the role of continuous measurement in the quantum to classical transition for a system with coupled internal (spin) and external (motional) degrees of freedom. Even when the measured motional degree of freedom can be treated…

Superlenses made of plasmonic materials and metamaterials have been exploited to image features of sub-diffractional scale. However, their intrinsic losses impose a serious restriction on the imaging resolution, which is a long-standing…

Classical Physics · Physics 2023-03-29 Fuxin Guan , Kebo Zeng , Zhaoyu Nie , Xiangdong Guo , Shaojie Ma , Qing Dai , John B. Pendry , Xiang Zhang , Shuang Zhang

In the long quest to identify and compensate the sources of decoherence in many-body systems far from the ground state, the varied family of Loschmidt echoes (LEs) became an invaluable tool in several experimental techniques. A LE involves…

Quantum Physics · Physics 2022-06-15 Claudia M. Sánchez , Ana Karina Chattah , Horacio M. Pastawski

We discuss the effect of semitransparency in a quantum-Zeno-like interaction-free measurement setup, a quantum-physics based approach that might significantly reduce sample damage in imaging and microscopy. With an emphasis on applications…

Quantum Physics · Physics 2014-12-03 Sebastian Thomas , Christoph Kohstall , Pieter Kruit , Peter Hommelhoff

Modulo sampling is a promising technology to preserve amplitude information that exceeds the observable range of analog-to-digital converters during the digitization of analog signals. Since conventional methods typically reconstruct the…

Signal Processing · Electrical Eng. & Systems 2026-02-19 Haruka Kobayashi , Ryo Hayakawa

The classical limit of quantum mechanics is discussed for closed quantum systems in terms of observational aspects. Initially, the failure of the limit h->0 is explicitly demonstrated in a model of two quantum mechanically interacting…

Quantum Physics · Physics 2008-09-29 R. M. Angelo

Quantum metrology, a cornerstone of quantum technologies, exploits entanglement and superposition to achieve higher precision than classical protocols in parameter estimation tasks. When combined with critical phenomena such as phase…

We consider the problem of correcting the errors incurred from sending classical or quantum information through a noisy quantum environment by schemes using classical information obtained from a measurement on the environment. We give a…

Quantum Physics · Physics 2015-06-26 M. Gregoratti , R. F. Werner

We consider the scenario where important signals are not strong enough to be separable from a large amount of noise. Such weak signals commonly exist in large-scale data analysis and play vital roles in many biomedical applications.…

Methodology · Statistics 2022-01-26 X. Jessie Jeng , Yifei Hu

We define a quantity, the so-called purity fidelity, which measures the rate of dynamical irreversibility due to decoherence, observed e.g in echo experiments, in the presence of an arbitrary small perturbation of the total (system +…

Chaotic Dynamics · Physics 2009-11-07 Tomaz Prosen , Thomas H. Seligman

An adaptive optics system with a single deformable mirror is being implemented on the THEMIS 90cm solar telescope. This system is designed to operate in the visible and is required to be as robust as possible in order to deliver the best…

Instrumentation and Methods for Astrophysics · Physics 2021-01-11 Michel Tallon , Éric Thiébaut , Maud Langlois , Bernard Gelly , Richard Douet , Clémentine Béchet , Loïc Denis , Gil Moretto

We investigate the time-dependent variance of the fidelity with which an initial narrow wavepacket is reconstructed after its dynamics is time-reversed with a perturbed Hamiltonian. In the semiclassical regime of perturbation, we show that…

Quantum Physics · Physics 2009-11-10 Cyril Petitjean , Philippe Jacquod

Channel simulation is to simulate a noisy channel using noiseless channels with unlimited shared randomness. This can be interpreted as the reverse problem to Shannon's noisy coding theorem. In contrast to previous works, our approach…

Information Theory · Computer Science 2025-06-06 Shi-Bing Li , Ke Li , Lei Yu