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S. Pádua

Bio: S. Pádua is an academic researcher from Universidade Federal de Minas Gerais. The author has contributed to research in topics: Photon & Spontaneous parametric down-conversion. The author has an hindex of 24, co-authored 82 publications receiving 2594 citations. Previous affiliations of S. Pádua include State University of New York System & University of Concepción.


Papers
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Journal ArticleDOI
TL;DR: There are hundreds of papers published in this field, some with hundreds of citations as discussed by the authors, and some possible technical applications and connections to other research areas, such as complementarity relations, Bell's inequality violation and entanglement.

318 citations

Journal ArticleDOI
TL;DR: In this article, a quantum eraser experiment using a Young double slit to create interference was reported. But the experiment was performed under ''delayed erasure'' circumstances, which is not the case in this paper.
Abstract: We report a quantum eraser experiment which actually uses a Young double slit to create interference. The experiment can be considered an optical analogy of an experiment proposed by Scully, Englert, and Walther [Nature (London) 351, 111 (1991)]. One photon of an entangled pair is incident on a Young double slit of appropriate dimensions to create an interference pattern in a distant detection region. Quarter-wave plates, oriented so that their fast axes are orthogonal, are placed in front of each slit to serve as which-path markers. The quarter-wave plates mark the polarization of the interfering photon and thus destroy the interference pattern. To recover interference, we measure the polarization of the other entangled photon. In addition, we perform the experiment under ``delayed erasure'' circumstances.

286 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that the two-photon state generated in the process of spontaneous parametric down-conversion in a thin crystal carries information about the angular spectrum of the pump beam.
Abstract: We show that the two-photon state generated in the process of spontaneous parametric down-conversion in a thin crystal carries information about the angular spectrum of the pump beam. This information transfer allows one to control the transverse correlation properties of the down-converted fields by manipulating the pump field, with consequences for a broad class of experiments. The effect is demonstrated theoretically and experimentally, in connection with the formation of fourth-order images by the down-converted beams.

280 citations

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TL;DR: In this article, a simple scheme for complete Bell-state measurement of photons using hyperentangled states was proposed, which requires only linear optics and single photon detectors, and is realizable with current technology.
Abstract: We propose a simple scheme for complete Bell-state measurement of photons using hyperentangled states---entangled in multiple degrees of freedom. In addition to hyperentanglement, our scheme requires only linear optics and single photon detectors, and is realizable with current technology. At the cost of additional classical communication, our Bell-state measurement can be implemented nonlocally. We discuss the possible application of these results to quantum dense coding and quantum teleportation.

217 citations

Journal ArticleDOI
TL;DR: An experiment to generate entangled states of D-dimensional quantum systems, qudits, by using transverse spatial correlations of two parametric down-converted photons to demonstrate that the generated states are entangled states.
Abstract: We report an experiment to generate entangled states of D-dimensional quantum systems, qudits, by using transverse spatial correlations of two parametric down-converted photons. Apertures with D slits in the arms of the twin photons define the qudit space. By manipulating the pump beam correctly, the twin photons will pass only by symmetrically opposite slits, generating entangled states between these different paths. Experimental results for qudits with D = 4 and 8 are shown. We demonstrate that the generated states are entangled states.

207 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors demonstrate the ability to multiplex and transfer data between twisted beams of light with different amounts of orbital angular momentum, which provides new opportunities for increasing the data capacity of free-space optical communications links.
Abstract: Researchers demonstrate the ability to multiplex and transfer data between twisted beams of light with different amounts of orbital angular momentum — a development that provides new opportunities for increasing the data capacity of free-space optical communications links.

3,556 citations

Journal ArticleDOI
19 Nov 2004-Science
TL;DR: This work has shown that conventional bounds to the precision of measurements such as the shot noise limit or the standard quantum limit are not as fundamental as the Heisenberg limits and can be beaten using quantum strategies that employ “quantum tricks” such as squeezing and entanglement.
Abstract: Quantum mechanics, through the Heisenberg uncertainty principle, imposes limits on the precision of measurement. Conventional measurement techniques typically fail to reach these limits. Conventional bounds to the precision of measurements such as the shot noise limit or the standard quantum limit are not as fundamental as the Heisenberg limits and can be beaten using quantum strategies that employ “quantum tricks” such as squeezing and entanglement.

2,421 citations

Journal ArticleDOI
Abstract: "Quantum sensing" describes the use of a quantum system, quantum properties or quantum phenomena to perform a measurement of a physical quantity Historical examples of quantum sensors include magnetometers based on superconducting quantum interference devices and atomic vapors, or atomic clocks More recently, quantum sensing has become a distinct and rapidly growing branch of research within the area of quantum science and technology, with the most common platforms being spin qubits, trapped ions and flux qubits The field is expected to provide new opportunities - especially with regard to high sensitivity and precision - in applied physics and other areas of science In this review, we provide an introduction to the basic principles, methods and concepts of quantum sensing from the viewpoint of the interested experimentalist

1,878 citations

Journal ArticleDOI
TL;DR: In this article, the basic elements of entanglement theory for two or more particles and verification procedures, such as Bell inequalities, entangle witnesses, and spin squeezing inequalities, are discussed.
Abstract: How can one prove that a given state is entangled? In this paper we review different methods that have been proposed for entanglement detection. We first explain the basic elements of entanglement theory for two or more particles and then entanglement verification procedures such as Bell inequalities, entanglement witnesses, the determination of nonlinear properties of a quantum state via measurements on several copies, and spin squeezing inequalities. An emphasis is given on the theory and application of entanglement witnesses. We also discuss several experiments, where some of the presented methods have been implemented.

1,639 citations

Journal ArticleDOI
TL;DR: A review of the progress in photonic quantum information processing can be found in this article, where the emphasis is given to the creation of photonic entanglement of various forms, tests of the completeness of quantum mechanics (in particular, violations of local realism), quantum information protocols for quantum communication, and quantum computation with linear optics.
Abstract: Multiphoton interference reveals strictly nonclassical phenomena. Its applications range from fundamental tests of quantum mechanics to photonic quantum information processing, where a significant fraction of key experiments achieved so far comes from multiphoton state manipulation. The progress, both theoretical and experimental, of this rapidly advancing research is reviewed. The emphasis is given to the creation of photonic entanglement of various forms, tests of the completeness of quantum mechanics (in particular, violations of local realism), quantum information protocols for quantum communication (e.g., quantum teleportation, entanglement purification, and quantum repeater), and quantum computation with linear optics. The scope of the review is limited to ``few-photon'' phenomena involving measurements of discrete observables.

1,156 citations