How to Measure Squeezing and Entanglement of Gaussian States without Homodyning
Jaromír Fiurášek,Nicolas J. Cerf +1 more
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This work proposes a scheme for measuring the squeezing, purity, and entanglement of Gaussian states of light that does not require homodyne detection and needs only beam splitters and single-photon detectors.Abstract:
We propose a scheme for measuring the squeezing, purity, and entanglement of Gaussian states of light that does not require homodyne detection. The suggested setup needs only beam splitters and single-photon detectors. Two-mode entanglement can be detected from coincidences between photodetectors placed on the two beams.read more
Citations
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Journal ArticleDOI
Quantum entanglement
TL;DR: In this article, the basic aspects of entanglement including its characterization, detection, distillation, and quantification are discussed, and a basic role of entonglement in quantum communication within distant labs paradigm is discussed.
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Entanglement in continuous-variable systems: recent advances and current perspectives
TL;DR: The theory of continuous-variable entanglement with special emphasis on foundational aspects, conceptual structures and mathematical methods has been studied in this paper, where the most important results on the separability and distillability of Gaussian states are discussed.
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Extremal entanglement and mixedness in continuous variable systems
TL;DR: The concept of average logarithmic negativity is introduced, showing that it allows a reliable quantitative estimate of continuo us variable entanglement by direct measurements of global and marginal generalized p-entropies.
Journal ArticleDOI
Computable measure of nonclassicality for light.
TL;DR: The entanglement potential detects nonclassicality, has a direct physical interpretation, and can be computed efficiently, which make it stand out from previously proposed non classicality measures.
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Gaussian measures of entanglement versus negativities: Ordering of two-mode Gaussian states
TL;DR: Gaussian measures and negativities are definitely inequivalent measures of entanglement on nonsymmetric two-mode Gaussian states, even when restricted to a class of extremal states, and some strong evidence is provided suggesting that they are as well bounded from above as they are shown to be.
References
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Book
Quantum Statistics of Linear and Nonlinear Optical Phenomena
Jan Perina,Neal B. Abraham +1 more
Abstract: The quantum statistical properties of radiation represent an important branch of modern physics with rapidly increasing applications in spectroscopy, quantum generators of radiation, optical communication, etc. They have also an increasing role in fields other than pure physics, such as biophysics, psychophysics, biology, etc. The present monograph represents an extension and continuation of the previous monograph of this author entitled Coherence of Light (Van Nostrand Reinhold Company, London 1972, translated into Russian in the Publishing House Mir, Moscow 1974) and of a review chapter in Progress in Optics, Vol. 18 (E. Wolf (Ed.), North-Holland Publishing Company, Amsterdam 1980), published just recently. It applies the fundamental tools of the coherent-state technique, as described in Coherence of Light, to particular studies of the quantum statistical properties of radiation in its interaction with matter. In particular, nonlinear optical processes are considered, and purely quantum phenomena such as antibunching of photons are discussed. This book will be useful to research workers in the fields of quantum optics and electronics, quantum generators, optical communication and solid-state physics, as well as to students of physics, optical engineering and opto-electronics.
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Quantum-noise matrix for multimode systems: U(n) invariance, squeezing, and normal forms.
R. Simon,N. Mukunda,B. Dutta +2 more
TL;DR: It is shown that all conceivable variance matrices can be generated through squeezed thermal states of the n-mode system and their symplectic transforms and developed in both the real and the complex forms for varianceMatrices.
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Direct estimations of linear and nonlinear functionals of a quantum state
Artur Ekert,Carolina Moura Alves,Daniel K. L. Oi,Michał Horodecki,Paweł Horodecki,Leong Chuan Kwek +5 more
TL;DR: A simple quantum network, based on the controlled-SWAP gate, is presented that can extract certain properties of quantum states without recourse to quantum tomography and is used as a basic building block for direct quantum estimations of both linear and nonlinear functionals of any density operator.
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Entanglement of formation for symmetric Gaussian states.
Geza Giedke,Geza Giedke,Michael M. Wolf,Michael M. Wolf,O. Krüger,Reinhard F. Werner,J. I. Cirac +6 more
TL;DR: It is shown that for a fixed amount of entanglement, two-mode squeezed states are those that maximize Einstein-Podolsky-Rosen-like correlations and this is the first instance in which this measure has been determined for genuine continuous variable systems.
Journal ArticleDOI
Method for direct detection of quantum entanglement.
Paweł Horodecki,Artur Ekert +1 more
TL;DR: This work views this method as a new form of quantum computation, namely, as a decision problem with quantum data structure, which provides a sharp separability test and estimation of amount of entanglement for two qubits.