Quantum parameter estimation promises a high-precision measurement in theory, however, how to design the optimal scheme specific scenario, especially under practical condition, is still serious problem that needs be solved case by due existence of multiple mathematical bounds and optimization methods. Depending on scenario considered, different may more or less suitable, both terms computationa...

The radiation caused by particles of one bunch in the collective electromagnetic field of the short oncoming bunch is studied. Quantum effects are calculated for the spectrum of radiated photons. Using this spectrum, the dependence of the relative energy loss δ on a quantum parameter κ is dicussed. It is shown that the behaviour of δ changes considerably with the increase of that parameter. In ...

The qubit depolarizing channel with noise parameter η transmits an input qubit perfectly with probability 1− η, and outputs the completely mixed state with probability η. We show that its complementary channel has positive quantum capacity for all η > 0. Thus, we find that there exists a single parameter family of channels having the peculiar property of having positive quantum capacity even wh...

Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement ascribed to 2D-FS. Although the isotropically averaged spectroscopic...