Entanglement induced by a single-mode heat environment

Abstract

A thermal field, which frequently appears in problems of decoherence, provides us with minimal information about the field. We study the interaction of the thermal field and a quantum system composed of two qubits and find that such a chaotic field with minimal information can nevertheless entangle the qubits which are prepared initially in a separable state. This simple model of a quantum register interacting with a noisy environment allows us to understand how memory of the environment affects the state of a quantum register

Entanglement induced by the two-mode thermal noise

“…In this the dependencies of the Peres-Horodecki parameter ε versus dimensionless time gt is presented for models with n 1 = n 2 = 0.3 (dashed line) and n 1 = n 2 = 1 (solid line). Comparing curves with that for one-photon [3] and degenerate two-photon [5] interaction, we find that contrary to above mentioned models the entanglement for considered model takes place for all instances only for sufficiently large intensities of the input cavity modes. The entanglement through nondegenerate two-photon interaction reveals the nonlinear behaviour in a similar way to the degenerate interaction but its value is less than that for aforementioned model with same values of input intensity.…”

“…M.Kim et al [3] and L.Zhou et al [5] have shown that, with even a very small amount of mixture λ, atomic entanglement is washed out both for one-photon and degenerate two-photon interaction.…”

“…Recently, S.Bose et al [2] have showed that entanglement can always arise in the interaction of an arbitrary large system in any mixed state with a single qubit in a pure state, and illustrated this using the Jaynes-Cummings interaction of a two-level atom in a pure state with a field in a thermal state at an arbitrary high temperature. M.Kim et al [3] have investigated the entanglement of two identical two-level atoms with one-photon transition induced by a single-mode thermal field. L.Zhou et al [4] have considered the same problem for nonidentical atoms.…”

Quantum entanglement and disentanglement of multi-atom systems

“…Nevertheless, the degradation process can be much slower when the parts of the system are coupled to a common rather than separate environments and, contrary to our intuition, might even entangle initially unentangled qubits. This effect, called the environment induced entanglement has been studied for discrete (atomic) [9][10][11][12][13][14][15], as well as for continuous variable systems [16,17]. A crucial parameter in the case of the atoms coupled to the same external environment is the collective damping [18][19][20], which results from an incoherent spontaneous exchange of photons between the qubits.…”

Control of atomic entanglement by the dynamic Stark effect

“…Practical realization of various features of quantum entanglement are obtained in atom-photon interactions in optical and microwave cavities. Several studies have been performed to quantify the entanglement generated in atom-photon interactions in cavities [7,8,9,10].…”