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8 pages, 751 KiB

Open AccessCommunication

Attosecond-Level Delay Sensing via Temporal Quantum Erasing

by Fabrizio Sgobba, Andrea Andrisani, Stefano Dello Russo, Mario Siciliani de Cumis and Luigi Santamaria Amato

Sensors 2023, 23(18), 7758; https://doi.org/10.3390/s23187758 - 8 Sep 2023

Cited by 3 | Viewed by 1249

Abstract

Traditional Hong-Ou-Mandel (HOM) interferometry, insensitive to photons phase mismatch, proved to be a rugged single-photon interferometric technique. By introducing a post-beam splitter polarization-dependent delay, it is possible to recover phase-sensitive fringes, obtaining a temporal quantum eraser that maintains the ruggedness of the original HOM with enhanced sensitivity. This setup shows promising applications in biological sensing and optical metrology, where high sensitivity requirements are coupled with the necessity to keep light intensity as low as possible to avoid power-induced degradation. In this paper, we developed a highly sensitive single photon birefringence-induced delay sensor operating in the telecom range (1550 nm). By using a temporal quantum eraser based on common path Hongr-Ou-Mandel Interferometry, we were able to achieve a sensitivity of 4 as for an integration time of

2 \cdot 10^{4}

s. Full article

(This article belongs to the Special Issue Quantum Sensors and Sensing Technology)

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14 pages, 872 KiB

Open AccessArticle

Local Quantum Uncertainty and Quantum Interferometric Power in an Anisotropic Two-Qubit System

by Nour Zidan, Atta Ur Rahman, Saeed Haddadi, Artur Czerwinski and Soroush Haseli

Universe 2023, 9(1), 5; https://doi.org/10.3390/universe9010005 - 21 Dec 2022

Cited by 17 | Viewed by 2962

Abstract

Investigating the favorable configurations for non-classical correlations preservation has remained a hotly debated topic for the last decade. In this regard, we present a two-qubit Heisenberg spin chain system exposed to a time-dependent external magnetic field. The impact of various crucial parameters, such as initial strength and angular frequency of the external magnetic field along with the state’s purity and anisotropy of the spin-spin on the dynamical behavior of quantum correlations are considered. We utilize local quantum uncertainty (LQU) and quantum interferometric power (QIP) to investigate the dynamics of quantum correlations. We show that under the critical angular frequency of the external magnetic field and the spin-spin anisotropy, quantum correlations in the system can be successfully preserved. LQU and QIP suffer a drop as the interaction between the system and field is initiated, however, are quickly regained by the system. This tendency is confirmed by computing a measure of non-classical correlations according to the Clauser–Horne–Shimony–Holt inequality. Notably, the initial and final preserved levels of quantum correlations are only varied when variation is caused in the state’s purity. Full article

(This article belongs to the Special Issue Theories and Applications of Quantum Entanglement)

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18 pages, 7709 KiB

Open AccessArticle

Correlation Technologies for Emerging Wireless Applications

by Sidina Wane, Fabien Ferrero, Thanh Vinh Dinh, Damienne Bajon, Lionel Duvillaret, Gwenaël Gaborit and Vincent Huard

Electronics 2022, 11(7), 1134; https://doi.org/10.3390/electronics11071134 - 2 Apr 2022

Cited by 7 | Viewed by 3053

Abstract

In this article, we introduce correlation technologies both at RF/mmWave and baseband frequencies. At RF and mmWave frequencies, power-spectra and energy-spectra metrics are introduced for measuring the power-density of mobile devices and systems. New ASIC-embedded smart connectors are developed for bringing correlation-based signal processing close to antenna modules. At baseband frequencies, DSP-based convolutional accelerators are proposed for fast and accurate measurement of EVM (error vector magnitude) using correlation technologies. Porting of the DSP-based convolutional accelerators into advanced fully depleted silicon-on-insulator (FDSOI)-based ASIC platforms for co-integration with adaptive RF/mmWave front-end modules will enable real-time extraction of auto-correlation and cross-correlation functions of stochastic signals. Perspectives for optically synchronized interferometric-correlation technologies are drawn for accurate measurements in noisy environments of stochastic EM fields using power-spectra and energy-spectra metrics. Adoption of correlation technologies will foster new paradigms relative to interactions of humans with smart devices and systems in randomly fluctuating environments. The resulting new paradigms will open new possibilities in communication theory for properly combining and reconciling information signal theory (Shannon information-based entropy) and physical information theory (statistical-physics-based entropy) into a unified framework. Full article

(This article belongs to the Special Issue EMC Analysis in Wireless Communication)

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9 pages, 396 KiB

Open AccessArticle

Initial Dynamics of Quantum Impurities in a Bose–Einstein Condensate

by Magnus G. Skou, Thomas G. Skov, Nils B. Jørgensen and Jan J. Arlt

Atoms 2021, 9(2), 22; https://doi.org/10.3390/atoms9020022 - 27 Mar 2021

Cited by 7 | Viewed by 3011

Abstract

An impurity immersed in a medium constitutes a canonical scenario applicable in a wide range of fields in physics. Though our understanding has advanced significantly in the past decades, quantum impurities in a bosonic environment are still of considerable theoretical and experimental interest. Here, we discuss the initial dynamics of such impurities, which was recently observed in interferometric experiments. Experimental observations from weak to unitary interactions are presented and compared to a theoretical description. In particular, the transition between two initial dynamical regimes dominated by two-body interactions is analyzed, yielding transition times in clear agreement with the theoretical prediction. Additionally, the distinct time dependence of the coherence amplitude in these regimes is obtained by extracting its power-law exponents. This benchmarks our understanding and suggests new ways of probing dynamical properties of quantum impurities. Full article

(This article belongs to the Special Issue Physics of Impurities in Quantum Gases)

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13 pages, 315 KiB

Open AccessArticle

A Unified Approach to Local Quantum Uncertainty and Interferometric Power by Metric Adjusted Skew Information

by Paolo Gibilisco, Davide Girolami and Frank Hansen

Entropy 2021, 23(3), 263; https://doi.org/10.3390/e23030263 - 24 Feb 2021

Cited by 10 | Viewed by 1926

Abstract

Local quantum uncertainty and interferometric power were introduced by Girolami et al. as geometric quantifiers of quantum correlations. The aim of the present paper is to discuss their properties in a unified manner by means of the metric adjusted skew information defined by [...] Read more.

(This article belongs to the Special Issue Information Geometric Characterization of Classical and Quantum Complex Systems)

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