Dissipative quantum repeater

Abstract

By implementing a quantum repeater protocol, our aim in this paper is the production of entanglement between two two-level atoms locating far from each other. To make our model close to experimental realizations, the atomic and field sources of dissipations are also taken into account. We consider eight of such atoms (1, 2, ..., 8) sequentially located in a line which begins (ends) with atom 1 (8). We suppose that, initially the four atomic pairs (i, i + 1), i = 1, 3, 5, 7 are mutually prepared in maximally entangled states. Clearly, the atoms 1, 8, the furthest atoms which we want to entangle them are never entangled, initially. To achieve the purpose of paper, at first we perform the interaction between the atoms (2, 3) as well as (6, 7) which results in the entanglement creation between (1, 4) and (5, 8), separately. In the mentioned interactions we take into account spontaneous emission rate (Γ ) for atoms and field decay rate from the cavities (κ) as two important and unavoidable dissipation sources. In the continuation, we transfer the entanglement to the objective pair (1, 8) by two methods: i) Bell state measurement (BSM), and ii) cavity quantum electrodynamics (QED). The successfulness of our protocol is shown via the evaluation of concurrence as the well-established measure of entanglement between the two (far apart) qubits (1,8). We also observe that, if one chooses the cavity and the atom such that κ = Γ holds, the effect of dissipations is effectively removed from the entanglement dynamics in our model. In this condition, the time evolutions of concurrence and success

Distributing entangled state using quantum repeater protocol: Trapped atomic ions in optomechanical cavities

“…Quantum repeater has been investigated in different systems such as quantum dots [18,19], trapped ions [20], Rydberg gates [21] and photonic system [22]. We have already considered quantum repeater protocols based on atomic systems in the presence of optomechanical cavity (OMC) [23] as well as optical cavity in the absence [24] and presence of dissipation [25,26]. Also, the distribution of entangled coherent states between two locations using quantum repeater protocol has been investigated [10].…”

Tracking control of two qubit entanglement using piecewise time-independent method

“…Even though there is no evidence of a direct connection between entanglement and coherence, there are studies attempting to establish such relation from the operational perspective [11][12][13]. Entanglement and decoherence are crucial in many potential applications, such as efficient information transmission through quantum coding or teleportation [14,15], data security transmitted through entanglement-based quantum cryptography [16,17], quantum networks [18,19] quantum metrology [20,21], and, generally, applications in information processing and quantum computing [22][23][24][25].…”

Quantum repeater protocol using an arrangement of QED–optomechanical hybrid systems

“…Heralded quantum repeater based on quantum dots has been investigated in [7]. Recently, we have considered the quantum repeater based on atoms where the entanglement has been swapped between atoms via performing interaction in the optical cavities [?, [8][9][10]. Quantum repeater is very useful in quantum internet issue [11].…”

“…As a result, the optomechanical systems can provide macroscopic systems by which one can find some quantum mechanical phenomena inherent in their structural mechanisms. Quantum repeater protocols have been considered in the presence of optical cavities in the previous literature [2,[8][9][10][58][59][60], moreover, the main feature of our present work is to extend, even partially, a particular quantum information protocol, in this case, the quantum repeaters, to the macroscopic quantum systems instead of microscopic quantum systems. In the present paper we want to consider the quantum repeater based on threelevel V-type atomic states, in which entanglement can be transferred to two distant atoms.…”