Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userFragility of quantum correlations and coherence in a multipartite photonic system
85
0
0.0
(
0
)
Added by
Radhakrishnan Chandrashekar Dr.
Publication date
2020
fields
Physics
and research's language is
English
Ask ChatGPT about the research
No Arabic abstract
Certain quantum states are well-known to be particularly fragile in the presence of decoherence, as illustrated by Schrodingers famous gedanken cat experiment. It has been better appreciated more recently that quantum states can be characterized in a hierarchy of quantum quantities such entanglement, quantum correlations, and quantum coherence. It has been conjectured that each of these quantities have various degrees of fragility in the presence of decoherence. Here we experimentally confirm this conjecture by preparing tripartite photonic states and subjecting them to controlled amounts of dephasing. When the dephasing is applied to all the qubits, we find that the entanglement is the most fragile quantity, followed by the quantum coherence, then mutual information. This is in agreement with the widely held expectation that multipartite quantum correlations are a highly fragile manifestation of quantumness. We also perform dephasing on one out of the three qubits on star and $ W bar{W} $ states. Here the distribution of the correlations and coherence in the state becomes more important in relation to the dephasing location.
rate research
Read More
We review some concepts and properties of quantum correlations, in particular multipartite measures, geometric measures and monogamy relations. We also discuss the relation between classical and total correlations
We study the multipartite quantum correlation (MQC) in a quantum transverse Ising model with the tunable triangular configuration. It is found that the anisotropic coupling can modulate the MQC in the frustrated phase and the MQC combined with its susceptibility can distinguish the frustrated and the nonfrustrated regimes in the ground state. Furthermore, we analyze the correlation properties at finite temperatures, where the MQC in the nonfrustrated phase is high at zero temperature but thermally fragile, which stems from the competition of the eigenvectors in the thermal state. Interestingly, in the frustrated phase, there is a trade-off relation between high quantum correlation and strong thermal robustness by tuning the anisotropic interactions, where the MQC can attain to a relatively higher value and have the well robustness to temperature at the same time. In addition, an experimental scheme for the MQC modulation via anisotropic coupling is discussed in the system of cold atoms trapped in an optical lattice.
Quantification of coherence lies at the heart of quantum information processing and fundamental physics. Exact evaluation of coherence measures generally needs a full reconstruction of the density matrix, which becomes intractable for large-scale multipartite systems. Here, we propose a systematic theoretical approach to efficiently estimating lower and upper bounds of coherence in multipartite states. Under the stabilizer formalism, the lower bound is determined by the spectrum estimation method with a small number of measurements and the upper bound is determined by a single measurement. We verify our theory with a four-qubit optical quantum system.We experimentally implement various multi-qubit entangled states, including the Greenberger-Horne-Zeilinger state, the cluster state, and the W state, and show how their coherence are efficiently inferred from measuring few observables.
In this brief report, we prove that robustness of coherence (ROC), in contrast to many popular quantitative measures of quantum coherence derived from the resource theoretic framework of coherence, may be sub-additive for a specific class of multipartite quantum states. We investigate how the sub-additivity is affected by admixture with other classes of states for which ROC is super-additive. We show that pairs of quantum states may have different orderings with respect to relative entropy of coherence, $l_{1}$-norm of coherence and ROC and numerically study the difference in ordering for coherence measures chosen pairwise.
We consider a multipartite system consisting of two noninteracting qubits each embedded in a single-mode leaky cavity, in turn connected to an external bosonic reservoir. Initially, we take the two qubits in an entangled state while the cavities and the reservoirs have zero photons. We investigate, in this six-partite quantum system, the transfer of quantum discord from the qubits to the cavities and reservoirs. We show that this transfer occurs also when the cavities are not entangled. Moreover, we discuss how quantum discord can be extracted from the cavities and transferred to distant systems by traveling leaking photons, using the input-output theory.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
