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Quantum metrology offers an enhanced performance in experiments such as gravitational wave-detection, magnetometry or atomic clocks frequency calibration. The enhancement, however, requires a delicate tuning of relevant quantum features…

Quantum Physics · Physics 2013-07-25 Jan Kolodynski , Rafal Demkowicz-Dobrzanski

Generalized quantum measurements are an important extension of projective or von Neumann measurements, in that they can be used to describe any measurement that can be implemented on a quantum system. We describe how to realize two…

A recent experiment demonstrated heterodyne detection-based frequency measurements with superradiant pulses from coherently pumped strontium atoms in an optical lattice clock system, while another experiment has analyzed the statistics of…

Quantum Physics · Physics 2022-12-05 Huihui Yu , Yuan Zhang , Qilong Wu , Chongxin Shan , Klaus Mølmer

When one performs a continuous measurement, whether on a classical or quantum system, the measurement provides a certain average rate at which one becomes certain about the state of the system. For a quantum system this is an average rate…

Quantum Physics · Physics 2009-11-10 Kurt Jacobs

Quantum metrology explores quantum effects to improve the measurement accuracy of some physical quantities beyond the classical limit. However, due to the interaction between the system and the environment, the decoherence can significantly…

Quantum Physics · Physics 2024-05-07 Cheng-Ge Liu , Cong-Wei Lu , Na-Na Zhang , Qing Ai

The high frequency primary power standard is univocally realized by means of a coaxial microcalorimeter, at least up to 40 GHz. The coaxial microcalorimeter is a broadband measurement system adjusted for effec-tive efficiency measurement of…

Instrumentation and Detectors · Physics 2021-03-09 Luciano Brunetti , Luca Oberto , Marco Sellone

In the wideband paradigm of pulsar timing, the time of arrival of a pulsar pulse is measured simultaneously with the corresponding dispersion measure from a frequency-resolved integrated pulse profile. We present a new method for performing…

Analog quantum simulators with global control fields have emerged as powerful platforms for exploring complex quantum phenomena. Despite these advances, a fundamental theoretical question remains unresolved: to what extent can such systems…

Quantum sensing encompasses highly promising techniques with diverse applications including noise-reduced imaging, super-resolution microscopy as well as imaging and spectroscopy in challenging spectral ranges. These detection schemes use…

Quantum Physics · Physics 2022-11-23 Felix Riexinger , Mirco Kutas , Björn Haase , Michael Bortz , Georg von Freymann

We consider statistical methods based on finite samples of locally randomized measurements in order to certify different degrees of multiparticle entanglement in intermediate-scale quantum systems. We first introduce hierarchies of…

Quantum Physics · Physics 2023-06-08 Andreas Ketterer , Satoya Imai , Nikolai Wyderka , Otfried Gühne

We propose a hybrid approach to simulate quantum many body dynamics by combining Trotter based quantum algorithm with classical dynamic mode decomposition. The interest often lies in estimating observables rather than explicitly obtaining…

Quantum Physics · Physics 2023-07-31 Niladri Gomes , Jia Yin , Siyuan Niu , Chao Yang , Wibe Albert de Jong

We derive fundamental bounds for general quantum metrological models involving both temporal or spatial correlations (mathematically described by quantum combs), which may be effectively computed in the limit of a large number of probes or…

Quantum Physics · Physics 2025-09-24 Stanislaw Kurdzialek , Francesco Albarelli , Rafal Demkowicz-Dobrzanski

We study a model of a two-level system (i.e. a qubit) in interaction with the electromagnetic field. By means of homodyne detection, one field-quadrature is observed continuously in time. Due to the interaction, information about the…

Quantum Physics · Physics 2009-11-11 Bas Janssens , Luc Bouten

Continuous-variable quantum cryptographic systems, including random number generation and key distribution, are often based on coherent detection. The essence of the security analysis lies in the randomness quantification. Previous analyses…

Quantum Physics · Physics 2018-10-24 Hongyi Zhou , Pei Zeng , Mohsen Razavi , Xiongfeng Ma

Time-continuous quantum error correction, necessary to protect quantum information under time-dependent Hamiltonians, relies on weak continuous syndrome measurements. Implementing these measurements requires a continuous coupling among at…

Quantum Physics · Physics 2026-03-18 Anton Halaski , Christiane P. Koch

Gaussian states, operations, and measurements are central building blocks for continuous-variable quantum information processing which paves the way for abundant applications, especially including network-based quantum computation and…

Quantum Physics · Physics 2021-07-06 Mengzhen Zhang

Efficient methods for characterizing the performance of quantum measurements are important in the experimental quantum sciences. Ideally, one requires both a physically relevant distinguishability measure between measurement operations and…

Quantum Physics · Physics 2015-06-12 Easwar Magesan , Paola Cappellaro

We present a generalized information-theoretic measure of synchronization in quantum systems. This measure is applicable to dynamics of anharmonic oscillators, few-level atoms, and coupled oscillator networks. Furthermore, the new measure…

While commonly used entanglement criteria for continuous variable systems are based on quadrature measurements, here we study entanglement detection from measurements of the Wigner function. These are routinely performed in platforms such…

Quantum Physics · Physics 2026-03-25 Shuheng Liu , Jiajie Guo , Qiongyi He , Matteo Fadel

Performance of quantum process estimation is naturally limited to fundamental, random, and systematic imperfections in preparations and measurements. These imperfections may lead to considerable errors in the process reconstruction due to…

Quantum Physics · Physics 2010-03-16 M. Mohseni , A. T. Rezakhani , J. T. Barreiro , P. G. Kwiat , A. Aspuru-Guzik