Bi-frequency illumination: a quantum-enhanced protocol

We propose a quantum-enhanced sensing protocol to measure the response of a target object to the frequency of a probe in a noisy and lossy scenario. In our protocol, a bi-frequency state illuminates a target embedded in a thermal bath, whose reflectivity $\eta(\omega)$ is frequency-dependent. After a lossy interaction with the object, we estimate the parameter $\lambda = \eta(\omega_2)-\eta(\omega_1)$ in the reflected beam, which captures information about the response of the object to different electromagnetic frequencies. Computing the quantum Fisher information $H$ relative to the parameter $\lambda$ in an assumed neighborhood of $\lambda \sim 0$ for a two-mode squeezed state ($H_Q$), and a coherent state ($H_C$), we show that a quantum enhancement in the estimation of $\lambda$ is obtained when $H_Q / H_C >1$. This quantum advantage grows with the mean reflectivity of the probed object, and is noise-resilient. We derive explicit formulas for the optimal observables, and propose a general experimental scheme based on elementary quantum optical transformations. Furthermore, our work opens the way to applications in both radar and medical imaging, in particular in the microwave domain

Bi-Frequency Illumination: A Quantum-Enhanced Protocol

Quantum-enhanced, idler-free sensing protocol to measure the response of a target object to the frequency of a probe in a noisy and lossy scenario is proposed. In this protocol, a target with frequency-dependent reflectivity �(�) embedded in a thermal bath is considered. The aim is to estimate the parameter � = �(�2 ) − �(�1 ), since it contains relevant information for different problems. For this, a bi-frequency quantum state is employed as the resource, since it is necessary to capture the relevant information about the parameter. Computing the quantum Fisher information H relative to the parameter � in an assumed neighborhood of � ≈ 0 for a two-mode squeezed state (HQ ), and a pair of coherent states (HC ), a quantum enhancement is shown in the estimation of �. This quantum enhancement grows with the mean reflectivity of the probed object, and is noise-resilient. Explicit formulas are derived for the optimal observables, and an experimental scheme based on elementary quantum optical transformations is proposed. Furthermore, this work opens the way to applications in both radar and medical imaging, in particular in the microwave domain.The authors acknowledge the support from the EU H2020 Quantum Flagship project QMiCS (820505). M.C. acknowledges support from the DP-PMI and FCT (Portugal) through scholarship PD/BD/135186/2017. M.C. and Y.O. thank the support from FundacAo para a Ciencia e a Tecnologia (Portugal), namely through the project UIDB/04540/2020, as well as from project The BlinQC supported by the EU H2020 QuantERA ERA-NET cofunded by Quantum Technologies and by FCT (QuantERA/0001/2017). M.S. acknowledge financial support from Basque Government QUANTEK project from ELKARTEK program (KK-2021/00070) and the Basque Government project IT1470-22, Spanish Ramon y Cajal Grant RYC-2020-030503-I and the project grant PID2021-125823NA-I00 funded by MCIN/AEI/10.13039/501100011033 and by "ERDF A way of making Europe" and "ERDF Invest in your Future," as well as from OpenSuperQ (820363) of the EU Flagship on Quantum Technologies, and the EU FET-Open projects Quromorphic (828826) and EPIQUS (899368)

Vajilla ecológica descartable

Fil: Labarta, María Graciela. Universidad Católica de Córdoba. Facultad de Ingeniería; ArgentinaFil: Manzanares, Rodrigo José. Universidad Católica de Córdoba. Facultad de Ingeniería; ArgentinaFil: Méndez Casariego, Mateo. Universidad Católica de Córdoba. Facultad de Ingeniería; ArgentinaFil: Ordoñez, Máximo. Universidad Católica de Córdoba. Facultad de Ingeniería; Argentin

Propagating Quantum Microwaves: Towards Applications in Communication and Sensing

The field of propagating quantum microwaves has started to receive considerable attention in the past few years. Motivated at first by the lack of an efficient microwave-to-optical platform that could solve the issue of secure communication between remote superconducting chips, current efforts are starting to reach other areas, from quantum communications to sensing. Here, we attempt at giving a state-of-the-art view of the two, pointing at some of the technical and theoretical challenges we need to address, and while providing some novel ideas and directions for future research. Hence, the goal of this paper is to provide a bigger picture, and -- we hope -- to inspire new ideas in quantum communications and sensing: from open-air microwave quantum key distribution to direct detection of dark matter, we expect that the recent efforts and results in quantum microwaves will soon attract a wider audience, not only in the academic community, but also in an industrial environment

Terrestrial Very-Long-Baseline Atom Interferometry:Workshop Summary

This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more km-scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions

Open-Air Microwave Entanglement Distribution for Quantum Teleportation

Funding Information: The authors thank R. Assouly, R. Dassonneville, and B. Huard for useful discussions. All authors acknowledge support from QMiCS (Grant No. 820505) of the EU Flagship on Quantum Technologies. T.G.-R. and M.S. acknowledge financial support from the Basque Government QUANTEK project under the ELKARTEK program (KK-2021/00070), the Spanish Ramón y Cajal Grant No. RYC-2020-030503-I, project Grant No. PID2021-125823NA-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” and “ERDF Invest in your Future”, OpenSuperQ (820363) of the EU Flagship on Quantum Technologies, the EU FET-Open projects Quromorphic (828826) and EPIQUS (899368), and IQM Quantum Computers under the project “Generating quantum algorithms and quantum processor optimization”. M.C. and Y.O. thank the support from FCT – Fundação para a Ciência e a Tecnologia (Portugal), namely through project UIDB/04540/2020, as well as from project TheBlinQC supported by the EU H2020 QuantERA ERA-NET Cofund in QuantumTechnologies and by FCT (QuantERA/0001/2017). M.C. acknowledges support from the DP-PMI and FCT through scholarship PD/BD/135186/2017. M.R., F.F., F.D., and K.F. acknowledge support from the German Research Foundation via Germany’s Excellence Strategy (EXC-2111-390814868), Elite Network of Bavaria through program ExQM, and the German Federal Ministry of Education and Research via project QUARATE (Grant No. 13N15380) and project QuaMToMe (Grant No. 16KISQ036). This research is part of the Munich Quantum Valley, which is supported by the Bavarian state government with funds from the Hightech Agenda Bayern Plus. The research of V.S. is supported by the Basque Government through the BERC 2022–2025 program and by the Ministry of Science, Innovation, and Universities: BCAM Severo Ochoa accreditation SEV-2017-0718. M.M. acknowledges funding from the European Research Council under Consolidator Grant No. 681311 (QUESS), from the Jane and Aatos Erkko Foundation and the Technology Industries of Finland Centennial Foundation through their Future Makers program, and from the Academy of Finland through its Centers of Excellence Program (Projects No. 312300 and No. 336810). | openaire: EC/H2020/820505/EU//QMiCS | openaire: EC/H2020/681311/EU//QUESSMicrowave technology plays a central role in current wireless communications, including mobile communication and local area networks. The microwave range shows relevant advantages with respect to other frequencies in open-air transmission, such as low absorption losses and low-energy consumption, and in addition, it is the natural working frequency in superconducting quantum technologies. Entanglement distribution between separate parties is at the core of secure quantum communications. Therefore, understanding its limitations in realistic open-air settings, especially in the rather unexplored microwave regime, is crucial for transforming microwave quantum communications into a mainstream technology. Here, we investigate the feasibility of an open-air entanglement distribution scheme with microwave two-mode squeezed states. First, we study the reach of direct entanglement transmission in open air, obtaining a maximum distance of approximately 500 m with parameters feasible for state-of-the-art experiments. Subsequently, we adapt entanglement distillation and entanglement swapping protocols to microwave technology in order to reduce the environment-induced entanglement degradation. The employed entanglement distillation helps to increase quantum correlations in the short-distance low-squeezing regime by up to 46%, and the reach of entanglement increases by 14% with entanglement swapping. Importantly, we compute the fidelity of a continuous-variable quantum teleportation protocol using open-air-distributed entanglement as a resource. Finally, we adapt this machinery to explore the limitations of quantum communication between satellites, where the impact of thermal noise is substantially reduced and diffraction losses are dominant.Peer reviewe

Propagating quantum microwaves : towards applications in communication and sensing

The field of propagating quantum microwaves is a relatively new area of research that is receiving increased attention due to its promising technological applications, both in communication and sensing. While formally similar to quantum optics, some key elements required by the aim of having a controllable quantum microwave interface are still on an early stage of development. Here, we argue where and why a fully operative toolbox for propagating quantum microwaves will be needed, pointing to novel directions of research along the way: from microwave quantum key distribution to quantum radar, bath-system learning, or direct dark matter detection. The article therefore functions both as a review of the state-of-the-art, and as an illustration of the wide reach of applications the future of quantum microwaves will open.Peer reviewe

Terrestrial Very-Long-Baseline Atom Interferometry: Workshop Summary

Summary of the Terrestrial Very-Long-Baseline Atom Interferometry Workshop held at CERN: https://indico.cern.ch/event/1208783/This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more km-scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions

Terrestrial Very-Long-Baseline Atom Interferometry Workshop (TVLBAI 2023)

This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more km-scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions