Decoherence-free creation of atom-atom entanglement in cavity via fractional adiabatic passage

We propose a robust and decoherence insensitive scheme to generate controllable entangled states of two three-level atoms interacting with an optical cavity and a laser beam. Losses due to atomic spontaneous transitions and to cavity decay are efficiently suppressed by employing fractional adiabatic passage and appropriately designed atom-field couplings. In this scheme the two atoms traverse the cavity-mode and the laser beam in opposite directions as opposed to other entanglement schemes in which the atoms are required to have fixed locations inside a cavity. We also show that the coherence of a traveling atom can be transferred to the other one without populating the cavity-mode.Comment: 4 pages, 5 figures, Submitted to Phys. Re

Synthesis of fast qudit gates by a train of coincident pulses

We propose an exact analytical method for the production of fast quantum gates in a system of d degenerate states, using a technique of a train of coincident pulses. It is an alternative to the adiabatic passage technique. This study exploits the Morris-Shore transformation and generalized quantum Householder reflection in which each of Householder reflection is implemented by n + m (n and m are arbitrary integers) sets of coincident pulses. Decoherence due to the population of the upper state is efficiently suppressed as the number of pulse sets (n and m) increases. It is remarkable that the upper state population is damped considerably, even for a small number of pulse sets, despite the fact that all the fields applied were on resonance with their transitions. In this method, simple Gaussian pulses with minimal pulse areas were used, which is easy to achieve experimentally. As a case study to validate the method, we implement the quantum Fourier transform in qutrit and ququad by a proper pulse train

Quantum state engineering in atom-cavity-laser systems by adiabatic passage (multi-photon states and entanglement)

DIJON-BU Sciences Economie (212312102) / SudocSudocFranceF

Sensors which can be used for remote quantum estimation

Quantum sensors have a significant advantage over their classic counterparts, and hence their practical application is of particular importance. However, in many practical scenarios, it is not possible to measure or estimate at close distances and endangers the security of the process. In this paper, with the help and inspiration of the quantum teleportation process, we propose the design of a sensor remotely estimating the parameter encoded into the quantum state of a quantum system. We show how the control over classical and quantum noises, affecting the sensor, can enhance the estimation. Moreover, the practical implementation of this project is discussed in detail

Enhanced alignment and orientation of polar molecules by vibrational resonant adiabatic passage

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