We investigate the role of the cross decay rates in a system composed by two electromagnetic modes interacting with the same reservoir. Two feasible experiments sensitive to the magnitudes and phases of these rates are described. We show that if the cross decay rates are appreciable there are states less exposed to decoherence and dissipation, and in limit situations a decoherence free subspace appears.

We propose a strategies not only to protect but also to enhance and revive the entanglement in a double Jaynes-Cummings model. We show that such surprising features arises when Zeno-like measurements are performed during the dynamical process.

Mechanical resonators represent one of the most promising candidates to mediate the interaction between different quantum technologies, bridging the gap between efficient quantum computation and long-distance quantum communication. In this letter, we introduce a novel interferometric scheme where the interaction of a mechanical resonator with input/output quantum pulses is controlled by an independent classical drive. We design protocols for state teleportation and direct quantum state transfer, between distant mechanical resonators. The proposed device, feasible with state-of-the-art technology, can serve as building block for the implementation of long-distance quantum networks of mechanical resonators.During the spectacular development of quantum technologies observed in the last decades, it has become clear that no single platform will emerge as the best candidate to perform the totality of all quantum information tasks [1]. For example, superconducting circuits [2] and atomic systems [3, 4] excel in quantum computation and quantum simulation. Photonic systems [5], among many other achievements, have proven able to implement quantum communication over unchallenged distances. The feasibility of building quantum systems of increasing size and complexity will strongly depend on our ability to develop a hybrid approach [6], exploiting different quantum technologies in large-scale quantum networks [7]. In this framework, micro-and nano-mechanical devices come through as potential links between different platforms, as they can be coupled to a plethora of different quantum systems [8][9][10]. So far, it has been experimentally explored the interaction of mechanical oscillators with ensembles of cold atoms [11], microwave and optical cavities [13][14][15][16][17][18][19][20], superconducting qubits [12], and single spins [21]. Using optomechanical devices, coherent conversion of microwave to optical photons [22, 23], and viceversa [24], has already been demonstrated.The interest in using mechanical resonators in quantum communication protocols has been steadily growing. Most recently, the interaction of mechanical resonators with travelling optical signals has been studied for the purpose of light-to-mechanical teleportation [28], qubit-to-light transduction [29], non-Gaussian state swapping [25], and entanglement generation [26,27]. Different schemes have been proposed to distribute entanglement among remote mechanical resonators [30,31]. However, a complete protocol for transferring arbitrary quantum states between distant mechanical resonators is still missing. In general, interconnecting remote quantum systems through propagating quantum signals is a highly challenging task. Quantum state transfer and teleportation have been realized for distant single atoms in a probabilistic way [32,33]. Quantum state teleportation has been implemented in a probabilistic fashion between distant trapped ions [34], as well as in a deterministic way between spatially separated atomic clouds [35].In this letter, we propose a nov...

We model a feasible experiment involving two interacting microwave cavities with very different quality factors. An excitation is initially present in the high Q cavity. Modeling the environment as linearly coupled oscillators, we find a Zeno-like behavior which should occur when the dissipation constant is large enough as compared to the unitary coupling.

We propose a feasible experiment in the context of cavity QED as follows: The initial state is a maximally entangled two cavity mode (M A , M B ). Next a sequence of atoms are sent, one at a time, and interact with mode M B . We show that the which-way information is initially stored only in M B is now distributed among the parties of the global system. The results realize known complementarity relations derived in the context of arbitrary qubits. We show that this dynamics may lead to a quantum eraser phenomenon provided that measurements of the probe atoms are performed in a basis which maximizes the visibility.