Optimal estimation of time-dependent gravitational fields with quantum optomechanical systems

We study the fundamental sensitivity that can be achieved with an ideal optomechanical system in the nonlinear regime for measurements of time-dependent gravitational fields. Using recently developed methods to solve the dynamics of a nonlinear optomechanical system with a time-dependent Hamiltonian, we compute the quantum Fisher information for linear displacements of the mechanical element due to gravity. We demonstrate that the sensitivity can not only be further enhanced by injecting squeezed states of the cavity field, but also by modulating the light--matter coupling of the optomechanical system. We specifically apply our results to the measurement of gravitational fields from small oscillating masses, where we show that, in principle, the gravitational field of an oscillating nano-gram mass can be detected based on experimental parameters that will likely be accessible in the near-term future. Finally, we identify the experimental parameter regime necessary for gravitational wave detection with a quantum optomechanical sensor

The Unruh-deWitt Detector and the Vacuum in the General Boundary formalism

We discuss how to formulate a condition for choosing the vacuum state of a quantum scalar field on a timelike hyperplane in the general boundary formulation (GBF) using the coupling to an Unruh-DeWitt detector. We explicitly study the response of an Unruh-DeWitt detector for evanescent modes which occur naturally in quantum field theory in the presence of the equivalent of a dielectric boundary. We find that the physically correct vacuum state has to depend on the physical situation outside of the boundaries of the spacetime region considered. Thus it cannot be determined by general principles pertaining only to a subset of spacetime.Comment: Version as published in CQ

EXACT2: the semantics of biomedical protocols

© 2014 Soldatova et al.; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.This article has been made available through the Brunel Open Access Publishing Fund.Background: The reliability and reproducibility of experimental procedures is a cornerstone of scientific practice. There is a pressing technological need for the better representation of biomedical protocols to enable other agents (human or machine) to better reproduce results. A framework that ensures that all information required for the replication of experimental protocols is essential to achieve reproducibility. Methods: We have developed the ontology EXACT2 (EXperimental ACTions) that is designed to capture the full semantics of biomedical protocols required for their reproducibility. To construct EXACT2 we manually inspected hundreds of published and commercial biomedical protocols from several areas of biomedicine. After establishing a clear pattern for extracting the required information we utilized text-mining tools to translate the protocols into a machine amenable format. We have verified the utility of EXACT2 through the successful processing of previously ‘unseen’ (not used for the construction of EXACT2) protocols. Results: The paper reports on a fundamentally new version EXACT2 that supports the semantically-defined representation of biomedical protocols. The ability of EXACT2 to capture the semantics of biomedical procedures was verified through a text mining use case. In this EXACT2 is used as a reference model for text mining tools to identify terms pertinent to experimental actions, and their properties, in biomedical protocols expressed in natural language. An EXACT2-based framework for the translation of biomedical protocols to a machine amenable format is proposed. Conclusions: The EXACT2 ontology is sufficient to record, in a machine processable form, the essential information about biomedical protocols. EXACT2 defines explicit semantics of experimental actions, and can be used by various computer applications. It can serve as a reference model for for the translation of biomedical protocols in natural language into a semantically-defined format.This work has been partially funded by the Brunel University BRIEF award and a grant from Occams Resources

Fig. 4. – A in Phelipanche chionistrae (Orobanchaceae): a new holoparasitic species from Cyprus

Fig. 4. – A. Phelipanche olbiensis (Coss.) Carlón et al. on Helichrysum L. in Crete, Greece; B. Phelipanche rosmarina (Beck) Banfi et al., Serra dos Candeeiros in Portugal. [Photos: A: A. Jagel & T. Schmitt; B: P. Pinho]Published as part of Rätzel, Stefan, Hand, Ralf, Christodoulou, Charalambos S. & Uhlich, Holger, 2021, Phelipanche chionistrae (Orobanchaceae): a new holoparasitic species from Cyprus, pp. 77-82 in Candollea 76 (1) on page 81, DOI: 10.15553/c2021v761a7, http://zenodo.org/record/568383

The effect of entanglement in gravitational photon-photon scattering

The differential cross section for gravitational photon-photon scattering calculated in Perturbative Quantum Gravity is shown to depend on the degree of polarization entanglement of the two photons. The interaction between photons in the symmetric Bell state is stronger than between not entangled photons. In contrast, the interaction between photons in the anti-symmetric Bell state is weaker than between not entangled photons. The results are interpreted in terms of quantum interference, and it is shown how they fit into the idea of distance-dependent forces.Comment: 6 pages, 3 figure

Euro+Med-Checklist Notulae, 10

This is the tenth of a series of miscellaneous contributions, by various authors, where hitherto unpublished data relevant to both the Med-Checklist and the Euro+Med (or Sisyphus) projects are presentedThis instalment deals with the families Amaranthaceae, Campanulaceae, Caryophyllaceae, Chenopodiaceae, Compositae, Crassulaceae, Cruciferae, Cyperaceae, Ericaceae, Euphorbiaceae, Gramineae, Labiatae, Leguminosae, Moraceae, Nyctaginaceae, Orobanchaceae, Pittosporaceae, Solanaceae, Verbenaceae and VitaceaeIt includes new country and area records and taxonomic and distributional considerations for taxa in Acacia (Vachellia), Airopsis, Amaranthus, Bougainvillea, Bromus, Carex, Cerastium, Citharexylum, Clinopodium, Datura, Euphorbia, Ficus, Hieracium, Hypopitys, Kalanchoe, Lobelia, Parthenocissus, Phelipanche, Pittosporum, Polypogon, Rorippa, Spinacia and Symphyotrichum, and a new combination in Clinopodium. © 2019 The Authors.Peer reviewe