235 research outputs found
Dynamics of Entanglement Transfer Through Multipartite Dissipative Systems
We study the dynamics of entanglement transfer in a system composed of two
initially correlated three-level atoms, each located in a cavity interacting
with its own reservoir. Instead of tracing out reservoir modes to describe the
dynamics using the master equation approach, we consider explicitly the
dynamics of the reservoirs. In this situation, we show that the entanglement is
completely transferred from atoms to reservoirs. Although the cavities mediate
this entanglement transfer, we show that under certain conditions, no
entanglement is found in cavities throughout the dynamics. Considering the
entanglement dynamics of interacting and non-interacting bipartite subsystems,
we found time windows where the entanglement can only flow through interacting
subsystems, depending on the system parameters.Comment: 8 pages, 11 figures, publishe in Physical Review
Entanglement properties in the Inhomogeneous Tavis-Cummings model
In this work we study the properties of the atomic entanglement in the
eigenstates spectrum of the inhomogeneous Tavis-Cummings Model. The
inhomogeneity is present in the coupling among the atoms with quantum
electromagnetic field. We calculate analytical expressions for the concurrence
and we found that this exhibits a strong dependence on the inhomogeneity.Comment: 5 pages, 5 figure
Abrupt Changes in the Dynamics of Quantum Disentanglement
Entanglement evolution in high dimensional bipartite systems under
dissipation is studied. Discontinuities for the time derivative of the lower
bound of entanglement of formation is found depending on the initial conditions
for entangled states. This abrupt changes along the evolution appears as
precursors of entanglement sudden death.Comment: 4 pages and 6 figures, submitted for publicatio
Global projection of lead-zinc supply from known resources
© 2018 by the authors. Lead and zinc are used extensively in the construction and automotive industries, and require sustainable supply. In order to understand the future availability of lead and zinc, we have projected global supplies on a country-by-country basis from a detailed global assessment of mineral resources for 2013. The model GeRS-DeMo was used to create projections of lead and zinc production from ores, as well as recycling for lead. Our modelling suggests that lead and zinc production from known resources is set to peak within 15 years (lead 2025, zinc 2031). For lead, the total supply declines relatively slowly post peak due to recycling. If additional resources are found, these peaks would shift further into the future. These results suggest that lead and zinc consumers will need to plan for the future, potentially by: seeking alternative supplies (e.g., mine tailings, smelter/refinery slags); obtaining additional value from critical metals contained in lead-zinc ore deposits to counter lower grade ores; identifying potential substitutes; redesigning their products; or by contributing to the development of recycling industries
Analog simulator of integro-differential equations with classical memristors
An analog computer makes use of continuously changeable quantities of a
system, such as its electrical, mechanical, or hydraulic properties, to solve a
given problem. While these devices are usually computationally more powerful
than their digital counterparts, they suffer from analog noise which does not
allow for error control. We will focus on analog computers based on active
electrical networks comprised of resistors, capacitors, and operational
amplifiers which are capable of simulating any linear ordinary differential
equation. However, the class of nonlinear dynamics they can solve is limited.
In this work, by adding memristors to the electrical network, we show that the
analog computer can simulate a large variety of linear and nonlinear
integro-differential equations by carefully choosing the conductance and the
dynamics of the memristor state variable. To the best of our knowledge, this is
the first time that circuits based on memristors are proposed for simulations.
We study the performance of these analog computers by simulating
integro-differential models related to fluid dynamics, nonlinear Volterra
equations for population growth, and quantum models describing non-Markovian
memory effects, among others. Finally, we perform stability tests by
considering imperfect analog components, obtaining robust solutions with up to
relative error for relevant timescales
Multipartite Entanglement Generation Assisted by Inhomogeneous Coupling
We show that controllable inhomogeneous coupling between two-level systems
and a common data bus provides a fast mechanism to produce multipartite
entanglement. Our proposal combines resonant interactions and engineering of
coupling strengths---between the qubits and the single mode---leading to well
defined entangled states. Furthermore, we show that, if the two-level systems
interact dispersively with the quantized mode, engineering of coupling
strengths allows the controlled access of the symmetric Hilbert space of
qubits.Comment: 5 pages, 4 figures. Submitted for publicatio
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