Relationship between the field local quadrature and the quantum discord of a photon-added correlated channel under the influence of scattering and phase fluctuation noise

Abstract

We study quantum correlations and discord in a bipartite continuous variable hybrid system formed by linear combinations of coherent states $|\alpha ⟩$ and single photon added coherent states (SPACS) of the form $|\psi {⟩}_{\text{dp(pa)}}=\mathcal{N}/\sqrt{2}({\hat{a}}^{†}|\alpha {⟩}_a|\alpha {⟩}_b\pm {\hat{b}}^{†}|\alpha {⟩}_a|\alpha {⟩}_b)$. We stablish a relationship between the quantum discord with a local observable (the quadrature variance for one sub-system) under the influence of scattering and phase fluctuation noise. For the pure states the quantum correlations are characterized by means of measurement induced disturbance (MID) with simultaneous quadrature measurements. In a scenario where homodyne conditional measurements are available we show that the MID provides an easy way to select optimal phases to obtain information of the maximal correlations in the channels. The quantum correlations of these entangled states with channel losses are quantitatively characterized with the quantum discord (QD) with a displaced qubit projector. We observe that as scattering increases, QD decreases monotonically. At the same time for the state $|\psi {⟩}_{\text{dp}}$, QD is more resistant to high phase fluctuations when the average photon number $n_0$ is bigger than zero, but if phase fluctuations are low, QD is more resistant if $n_0=0$. For the dp model with scattering, we obtain an analytical expression of the QD as a function of the observable quadrature variance in a local sub-system. This relation allows us to have a way to obtain the degree of QD in the channel by just measuring a local property observable such as the quadrature variance. For the other model this relation still exists but is explored numerically. This relation is an important result that allows to identify quantum processing capabilities in terms of just local observables.

arXiv comment27 pages, 14 figures

References in corpus (37)

• Quantum information with continuous variables
• Introducing Quantum Discord
• Classical, quantum and total correlations
• Photonic quantum technologies
• The classical-quantum boundary for correlations: discord and related measures
• Quantum teleportation between light and matter
• Unified View of Quantum and Classical Correlations
• Negativity of the Wigner function as an indicator of nonclassicality
• On the role of entanglement in quantum computational speed-up
• Entanglement by a beam splitter: nonclassicality as a prerequisite for entanglement
• Almost all quantum states have non-classical correlations
• Quantum discord as resource for remote state preparation
• Non-Markovian Dynamics of Quantum Discord
• Efficient Quantum Computation using Coherent States
• Deterministic quantum teleportation of photonic quantum bits by a hybrid technique
• Open-System Dynamics of Entanglement
• Tunable ion-photon entanglement in an optical cavity
• Entangling quantum and classical states of light
• Operational Significance of Discord Consumption: Theory and Experiment
• Continuous variable entanglement on a chip
• Monogamy of quantum correlations - a review
• Quantum Physics of Simple Optical Instruments
• Versatile Wideband Balanced Detector for Quantum Optical Homodyne Tomography
• Remote state preparation and teleportation in phase space
• Multi-qubit entanglement in bi-directional chiral waveguide QED
• Continuous-variable quantum teleportation with non-Gaussian entangled states generated via multiple-photon subtraction and addition
• Faithful nonclassicality indicators and extremal quantum correlations in two-qubit states
• Two-photon entanglement in multi-qubit bi-directional waveguide QED
• Exploring Macroscopic Entanglement with a Single Photon and Coherent States
• Generation of quantum discord between ionic qubits via noisy processes
• Homodyne detection as a near-optimum receiver for phase-shift keyed binary communication in the presence of phase diffusion
• Experimental estimation of quantum discord for polarization qubit and the use of fidelity to assess quantum correlations
• Generation of hybrid entanglement between a single-photon polarization qubit and a coherent state
• Non-Gaussian quantum discord for Gaussian states
• Quantum discord of Bell cat-states under amplitude damping
• Experimental Verification of Quantum Discord in Continuous-Variable States
• Vibrations of a Columnar Vortex in a Trapped Bose-Einstein Condensate

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