In this work we consider a bipartite system consisting of magnetic dipoles, initially characterized by product-states uncorrelated until the dynamics of evolution is established by magnetic dipole interaction. We reproduce the dynamic behavior of the entanglement produced by the magnetic dipole interaction through its temporal dependence, connection with local quantum coherences or symmetries of initial states and interaction parameters, thus establishing criteria that extremize the entanglement. We also investigated the entanglement production capacity of the magnetic dipole interaction for some classes of states with lower purities, with and without initial entanglement, thus identifying relevant aspects between purity, symmetry and necessary local quantum coherences. We show, above all, that some classes of partially entangled states can preserve or generate maximum entanglement under magnetic dipole interaction for different instants of time.
In this work we consider a bipartite system consisting of magnetic dipoles, initially characterized by product-states uncorrelated until the dynamics of evolution is established by magnetic dipole interaction. We reproduce the dynamic behavior of the entanglement produced by the magnetic dipole interaction through its temporal dependence, connection with local quantum coherences or symmetries of initial states and interaction parameters, thus establishing criteria that extremize the entanglement. We also investigated the entanglement production capacity of the magnetic dipole interaction for some classes of states with lower purities, with and without initial entanglement, thus identifying relevant aspects between purity, symmetry and necessary local quantum coherences. We show, above all, that some classes of partially entangled states can preserve or generate maximum entanglement under magnetic dipole interaction for different instants of time.
In this work, the asymmetry properties of quantum states associated with the Hamiltonian generator of the dynamics of the magnetic dipole interaction are investigated and their relationships with the production of entanglement are identified. Are also explored the types of separable or partially entangled quantum states that can be used as a resource in the entanglement distribution protocol, where we use IBM quantum processors to test the results with simulations and experiments performed remotely. Furthermore, a state preparation algorithm is presented that allows simulating and performing experiments with general quantum measurements and quantum instruments, as well as noisy quantum channels. In the topic about the properties of asymmetry and entanglement production, classes of pure and mixed quantum states consisting of 2 qubits evolved under magnetic dipole interaction (MDI) are considered.The asymmetry measure used is based on the Wigner-Yanase skew information between the quantum state and the Hamiltonian of the IDM, whose dependence is provided by the interaction parameters and initial conditions of the system. The local asymmetry associated with the evolved state is investigated, which is characterized by its dependence on the interaction parameters, local and temporal parameters, allowing the establishment of indirect relationships with the entanglement dynamics generated by MDI. The asymmetry related to the element of the unitary group responsible for the dynamics of the MDI is also analyzed, being useful to understand the dynamic character regarding the Wigner-Yanase asymmetry and to establish dynamic links with other properties. On the other hand, regarding the entanglement distribution protocol, the role of separable and partially entangled states are explored in the context of the Bell-diagonal class of states, analyzing the probabilistic entanglement distribution, where it involves selective projective measures, and the deterministic entanglement distribution, where it involves the action of non-selective general quantum measurements. Finally, with the proposal of a state preparation algorithm based on the relationship between the action of quantum channels and isometry, it was possible to carry out simulations and experiments on IBM quantum processors in general quantum measurements, quantum instruments and noisy quantum channels applied to qudits, allowing, in this way, to handle and develop in a simpler way the applications that until then were complex to simulate.
We consider multiqubit systems and relate quantitatively the problems of generating cluster states with high values of concurrence of assistance, and of generating states with maximal bipartite entanglement. We prove an upper bound for the concurrence of assistance. We consider dynamics of spin-1∕2 systems that model qubits, with different couplings and possible presence of magnetic field, to investigate the appearance of the discussed entanglement properties. We find that states with maximal bipartite entanglement can be generated by an isotropic XY Hamiltonian, and their generation can be controlled by the initial state of one of the spins. The same Hamiltonian is capable of creating states with high concurrence of assistance from a suitably chosen initial state. We show that the production of graph states using the Ising Hamiltonian is controllable via a single-qubit rotation of one spin-1∕2 subsystem in the initial multiqubit state. We show that the property of Ising dynamics to convert a product-state basis into a special maximally entangled basis is temporally enhanced by the application of a suitable magnetic field. Similar basis transformations are found to be feasible in the case of isotropic XY couplings with a magnetic field.
Abstract We examine the quantum dynamics of both a single spin- J particle and a pair of spin- J particles in the presence of static and rotating magnetic fields, which can be important for qudit-based quantum technologies. Notably, we find resonant, periodic oscillations between two maximally stretched states, irrespective of the value of J . Additionally, we observe periodic transitions between sublevels with magnetic quantum numbers of opposite signs. The dynamics also exhibit a periodic transfer of the spin to the maximally stretched state, starting from the ground state of the initial Hamiltonian. For a pair of spins, we derive various resonance conditions and further analyze the entanglement generated by dipole–dipole interactions. In the case of two spin-1/2 particles, the entanglement dynamics reveal resonances and kinks in the maximum entanglement, and their criteria can be obtained from the energy spectrum. Strikingly, we show that the kink can be exploited to engineer the entanglement dynamics. Finally, we briefly discuss the regime of weak dipolar interactions, which are relevant for dipolar Bose–Einstein condensates.
We analyze entanglement dynamics and transfer in a system composed of two initially correlated two-level atoms, in which each atom is coupled with another atom interacting with its own reservoir.Considering atomic dipole-dipole interactions, the results show that dipole-dipole interactions restrain the entanglement birth of the reservoirs, and a parametric region of dipole-dipole interaction strength exists in which the maximal entanglement of two initially uncorrelated atoms is reduced.The transfer of entanglement shows obvious different behaviors in two initial Bell-like states.
Introduction: In this study, we investigate the dynamics of the Entanglement in a two-spin system with long-range interaction.Method: For this purpose, we use negativity as the entanglement measurement. Using the time evolution operator, we obtain entanglement dynamics of the system at time t. We consider two different initial states and investigate the dynamical behavior of the system for all of them separately. Finally, we consider both J and D as a function of R and then study the time evolution of the entanglement in different R.Results: We find that in the long-range interaction, the R dependence of the dynamical behavior in the two systems is different. Depending on the initial states, the DM interaction and the magnetic field have no effect on the entanglement dynamics.
Abstract This research delves into the dynamic evolution of bipartite entanglement and nonclassical correlations within a two-spin system governed by dipole-dipole interactions and Dzyaloshinsky-Moriya (DM) coupling, while affected by intrinsic decoherence (ID). Beginning with the initialization of the bipartite system in a Werner state, we investigate how ID, dipolar coupling parameters, DM interaction strength, and uniform magnetic field strengths influence the progression of quantum entanglement and nonclassical correlations. Logarithmic negativity serves as a metric for quantifying entanglement, while quantum discord is employed to probe nonclassical correlations beyond entanglement. Our results highlight that strategic adjustments to the system parameters can alleviate the undesirable impact of ID. Moreover, the choice of initial state and its degree of pureness significantly influences the levels of entanglement and quantum discord within the dipolar-coupled spins system.