Quantum correlations between each qubit in a two-atom system and the environment in terms of interatomic distance

The quantum correlations between a qubit and its environment are described quantitatively in terms of interatomic distance. Specifically, considering a realistic system of two two-level atoms and taking into account the dipole-dipole interaction and collective damping, the quantum entanglement and quantum discord are investigated, during the dissipative process, as a function of the interatomic distance. For atoms that are initially maximally entangled, it turns out that there is a critical distance where each atom is maximally quantum correlated with its environment. Counterintuitively, the approach of the two atoms can maximize the entanglement between each one and the environment and, even at the same distance, minimize the loss of entanglement between the pair.Comment: 5 pages, 3 figure

Genotype × Environment Interactions of Industrial Hemp Cultivars Highlight Diverse Responses to Environmental Factors

Starting with the 2014 Farm Bill, hemp (Cannabis sativa L.) is being re-introduced as an industrial crop in the United States. Since the crop has been absent for over 70 yr, little is known regarding the genetic mechanisms controlling economically relevant traits. Particularly, with federal legality of the crop hinging on a stringent tetrahydrocannabinol (THC) content of 0.3% or less, it is necessary to assess variance in this trait due to environmental effects and genotype × environment interactions (GEI) to avoid running afoul of federal law. Understanding how physical and biochemical traits respond to the environment also plays a strong role in selecting and developing appropriate cultivars for production in diverse growing regions. In 2016 we performed cultivar trials in multiple environments in Colorado to assess performance characteristics of a diverse set of germplasm from breeding programs across Europe and Asia. From these data, we were able to identify traits nearly entirely controlled by genetic factors, like days to maturity and THC and cannabidiol (CBD) production. We also identified traits strongly influenced by the environment and GEI, like grain yield, plant height, and water use. Individual cultivars also exhibited widely varying degrees of sensitivity to the environment. This underscores the importance of continued work to characterize genetic control of hemp traits to expedite breeding of cultivars that are well-adapted to target growing region

Quantumness Measures for a System of Two Qubits Interacting with a Field in the Presence of the Time-Dependent Interaction and Kerr Medium

In this work, we introduce the standard Tavis-Cummings model to describe two-qubit system interacting with a single-mode field associated to power-law (PL) potentials. We explore the effect of the time-dependent interaction and the Kerr-like medium. We solve the Schrödinger equation to obtain the density operator that allows us to investigate the dynamical behaviour of some quantumness measures, such as von Neumann entropy, negativity and Mandel’s parameter. We provide how these entanglement measures depend on the system parameters, which paves the way towards better control of entanglement generation in two-qubit systems. We find that the enhancement and preservation of the atoms-field entanglement and atom-atom entanglement can be achieved by a proper choice of the initial parameters of the field in the absence and presence of the time-dependent interaction and Kerr medium. We examine the photons distribution of the field and determine the situations for which the field exhibits super-poissonian, poissonian or sub-poissonian distribution

Quantum Fisher information for a single qubit system

The Fisher information is used for quantum state estimation and considered as a physical resource associated with various quantities. The concept of Fisher information in terms of the atomic density operator is introduced. We give the correlation between the Fisher information and quantum entanglement during the time evolution for a trapped ion in laser field. The effect of the initial state setting on the classical Fisher information and quantum Fisher information is examined. The results show that the Fisher information is efficacious tool to study single qubit dynamics as an indicator of entanglement under certain conditions. Our observations may have important implications in exploiting this quantity in quantum information processing and transmission

Quantum transfer energy in the framework of time-dependent dipole-dipole interaction

In this work, we examine the process of the quantum transfer of energy considering time-dependent dipole-dipole interaction in a dimer system characterized by two-level atom systems. By taking into account the effect of the acceleration and speed of the atoms in the dimer coupling, we demonstrate that the improvement of the probability for a single-excitation transfer energy extremely benefits from the incorporation of atomic motion effectiveness and the energy detuning. We explore the relevance between the population and entanglement during the time-evolution and show that this kind of nonlocal correlation may be generated during the process of the transfer of energy. Our work may provide optimal conditions to implement realistic experimental scenario in the transfer of the quantum energy. Keywords: Quantum energy transfer, Quantum acceleration and speed, Dipole-dipole interaction, Population, Dimer system, Two-level atom system, Quantum correlation