Quantum correlations in separable multi-mode states and in classically entangled light
arXiv:1903.00469 · doi:10.1088/1361-6633/ab0c6b
Abstract
In this review we discuss intriguing properties of apparently classical optical fields, that go beyond purely classical context and allow us to speak about quantum characteristics of such fields and about their applications in quantum technologies. We briefly define the genuinely quantum concepts of entanglement and steering. We then move to the boarder line between classical and quantum world introducing quantum discord, a more general concept of quantum coherence, and finally a controversial notion of classical entanglement. To unveil the quantum aspects of often classically perceived systems, we focus more in detail on quantum discordant correlations between the light modes and on nonseparability properties of optical vector fields leading to entanglement between different degrees of freedom of a single beam. To illustrate the aptitude of different types of correlated systems to act as quantum or quantum-like resource, entanglement activation from discord, high-precision measurements with classical entanglement and quantum information tasks using intra-system correlations are discussed. The common themes behind the versatile quantum properties of seemingly classical light are coherence, polarization and inter and intra--mode quantum correlations.
39 pages, 8 figures
References in corpus (67)
- Entanglement of Formation of an Arbitrary State of Two Qubits
- Quantum information with continuous variables
- Gaussian Quantum Information
- Introducing Quantum Discord
- Classical, quantum and total correlations
- Peres-Horodecki separability criterion for continuous variable systems
- On the Measurement of Qubits
- Quantum Coherence as a Resource
- The classical-quantum boundary for correlations: discord and related measures
- Steering, Entanglement, Nonlocality, and the EPR Paradox
- Operational Resource Theory of Coherence
- Measuring Quantum Coherence with Entanglement
- Continuous variable quantum information: Gaussian states and beyond
- Entanglement, EPR-correlations, Bell-nonlocality, and Steering
- Quantum versus classical correlations in Gaussian states
- Gaussian quantum discord
- No-local-broadcasting theorem for quantum correlations
- Quantum information transfer from spin to orbital angular momentum of photons
- Measures and applications of quantum correlations
- Frozen Quantum Coherence
- Linking Quantum Discord to Entanglement in a Measurement
- Polarization squeezing and continuous-variable polarization entanglement
- All non-classical correlations can be activated into distillable entanglement
- Classical entanglement in polarization metrology
- Measuring Gaussian quantum information and correlations using the Renyi entropy of order 2
- Bell-like inequality for spin-orbit separability of a classical laser beam
- Characterizing the entanglement of bipartite quantum systems
- Classical entanglement: Oxymoron or resource?
- Quantum discord bounds the amount of distributed entanglement
- Quantum cost for sending entanglement
- Classically entangled optical beams for high-speed kinematic sensing
- Classical wave-optics analogy of quantum information processing
- An experimental demonstration of single photon nonlocality
- Separable states can be used to distribute entanglement
- Monogamy of quantum correlations - a review
- Classifying directional Gaussian quantum entanglement, EPR steering and discord
- Distilling common randomness from bipartite quantum states
- Topological phase for spin-orbit transformations on a laser beam
- Non-classicality criteria from phase-space representations and information-theoretical constraints are maximally inequivalent
- Optimality of Gaussian Discord
- Broadcast copies reveal the quantumness of correlations
- Experimental distribution of entanglement with separable carriers
- Quantum Discord and its Role in Quantum Information Theory
- Experimental entanglement distribution by separable states
- Tripartite non-separability in classical optics
- Conservation relation of nonclassicality and entanglement for Gaussian states in a beam-splitter
- Distributing Entanglement with Separable States
- Quantum Entanglement and the Two-Photon Stokes Parameters
- Maximum-likelihood estimation prevents unphysical Mueller matrices
- Measurement-induced disturbances and nonclassical correlations of Gaussian states
- Experimental entanglement activation from discord in a programmable quantum measurement
- A pedagogical overview of quantum discord
- Depolarization remote sensing by orthogonality breaking
- The geometric approach to quantum correlations: Computability versus reliability
- Distribution of continuous-variable entanglement by separable Gaussian states
- Assessing the Polarization of a Quantum Field from Stokes Fluctuation
- Bounds on general entropy measures
- Multipartite Einstein-Podolsky-Rosen steering sharing with separable states
- Single- and two-mode quantumness at a beam splitter
- Improving continuous-variable entanglement distribution by separable states
- Topological phase structure of vector vortex beams
- Quantumness of Gaussian Discord: Experimental Evidence and Role of System-Environment Correlations
- Entanglement sharing with separable states
- High-dimensional quantum channel estimation using classical light
- Entangling the whole by beam splitting a part
- No-activation theorem for Gaussian nonclassical correlations by Gaussian operations
- Entanglement distribution and quantum discord
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- Entanglement: Quantum or Classical?
- Quantum versus classical entanglement: eliminating the issue of quantum nonlocality
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- Quantum correlations in -symmetric systems
- Old experiments in new light: Young's double-slit and Stern-Gerlach experiments in liquid crystal microcavities
- Quantum Radars and Lidars: Concepts, realizations, and perspectives
- Conditional probability framework for entanglement and its decoupling from tensor product structure
- Bell inequality violation by entangled single photon states generated from a laser, a LED or a Halogen lamp
- Entanglement of observables: Quantum conditional probability approach
- Quantumness Beyond Entanglement: The Case of Symmetric States
- Quantum-like representation of neuronal networks' activity: modeling "mental entanglement"
- Emulation of quantum measurements with mixtures of coherent states
- Correlations for subsets of particles in symmetric states: what photons are doing within a beam of light when the rest are ignored
- Quantum correlations beyond entanglement in a classical-channel model of gravity
- Classical Optical Analogue of Quantum Discord
- Graded-index optical fiber emulator of an interacting three-atom system: illumination control of particle statistics and classical non-separability