How to observe and quantify quantum-discorded states via correlations
arXiv:1907.08130 · doi:10.1103/PhysRevA.100.022321
Abstract
Quantum correlations between parts of a composite system most clearly reveal themselves through entanglement. Designing, maintaining, and controlling entangled systems is very demanding, which raises the stakes for understanding the efficacy of entanglement-free, yet quantum, correlations, exemplified by quantum discord. Discord is defined via conditional mutual entropies of parts of a composite system, and its direct measurement is hardly possible even via full tomographic characterization of the system state. Here we design a simple protocol to detect and quantify quantum discord in an unentangled bipartite system. Our protocol relies on a characteristic of discord that can be extracted from repeated direct measurements of certain correlations between subsystems of the bipartite system. The proposed protocol opens a way of extending experimental studies of discord to electronic systems but can also be implemented in quantum-optical systems.
arXiv comment10 pages, 9 figures. arXiv admin note: substantial text overlap with arXiv:1901.11514
References in corpus (30)
- Quantum entanglement
- Introducing Quantum Discord
- Classical, quantum and total correlations
- The classical-quantum boundary for correlations: discord and related measures
- Quantum discord and the power of one qubit
- Necessary and sufficient condition for non-zero quantum discord
- On the Power of One Bit of Quantum Information
- Experimental quantum computing without entanglement
- An Electronic Mach-Zehnder Interferometer
- Sudden transition between classical and quantum decoherence
- Almost all quantum states have non-classical correlations
- Quantum discord as resource for remote state preparation
- Quantum enhanced measurements without entanglement
- Entanglement and the Power of One Qubit
- Computing quantum discord is NP-complete
- The problem with the geometric discord
- Quantum discord and its allies: a review
- Comparative investigation of the freezing phenomena for quantum correlations under nondissipative decoherence
- Generic emergence of classical features in quantum Darwinism
- Observable measure of bipartite quantum correlations
- Experimentally Witnessing the Quantumness of Correlations
- Measuring bipartite quantum correlations of an unknown state
- Quantum discord cannot be shared
- Criteria for measures of quantum correlations
- Robust Electron Pairing in the Integer Quantum Hall Effect Regime
- An Electronic Quantum Eraser
- Experimental estimation of quantum discord for polarization qubit and the use of fidelity to assess quantum correlations
- Single-experiment-detectable nonclassical correlation witness
- Detecting the quantum discord of an unknown state by a single observable
- Power of One Bit of Quantum Information in Quantum Metrology