Efficient qubit detection using alkaline-earth-metal ions and a double stimulated Raman adiabatic process

Abstract

We present a scheme for robust and efficient projection measurement of a qubit consisting of the two magnetic sublevels in the electronic ground state of alkali earth metal ions. The scheme is based on two stimulated Raman adiabatic passages (STIRAP) involving four partially coherent laser fields. We show how the efficiency depends on experimentally relevant parameters: Rabi frequencies, pulse widths, laser linewidths, one-and two-photon detunings, residual laser power, laser polarization and ion motion.

Quantum Gates and Multiparticle Entanglement by Rydberg Excitation Blockade and Adiabatic Passage

“…In alkali atoms Rydberg states with principal quantum number n > 70 have lifetimes * 100 s and experience a dipole-dipole interaction strength, E=@, above 100 2 MHz when atoms are separated less than 5 m [3]. The accompanying suppression of excitation for n up to 80 [4,5] and the influence of the excitation blockade on coherent collective dynamics [6] were observed in cold gases.We propose to combine the Rydberg blockade mechanism with the rapid adiabatic laser pulse sequence known from stimulated Raman adiabatic passage (STIRAP) [7][8][9][10]. We consider atoms with two lower levels and a Rydberg level in a ladder structure coupled by two resonant laser fields with Rabi frequencies 1 and r as shown in Fig.…”

Chirped multiphoton adiabatic passage for a four-level ladder-type Rydberg excitation

“…It does not have any contribution from the unstable intermediate state. Then a complete transfer from |g to |r can be achieved by adiabatically changing the dark state superposition, that is, performing a pair of optical pulses in a counterintuitive order [21,39]. For a four-level atomic system considered in the present work, by diagonalizng Hamiltonian (1) we find due to the different symmetry from the three-level system, there is no dark state which is immune to the two intermediate states |m and |e .…”

Excitation of Rydberg states of atoms by adiabatic transfer of populations

“…The generalization of STIRAP on the multi-level systems, the theoretical and experimental investigations of peculiarities of this method, its advantages over the other methods of the population transfer and the numerous applications are studied in details [14][15][16][17]. However, in all these works the adiabatic state is taken as a basis for the state corresponding to the zero eigenstate of interaction Hamiltonian.…”