Resolved fine and hyperfine state-to-state rate coefficients for the rotational transitions of C3N induced by collision with He

The fine and hyperfine resolved state-to-state rate coefficients for the rotational (de)excitation of C3N by collision with helium are computed. To this aim a two dimensional potential energy surface is calculated for this system. The recoupling method is used to obtain the fine and hyperfine structure resolved rate coefficients from spin-free Close Coupling calculations. These results are compared with those given by the Infinite Order Sudden Approximation and the M-randomizing Limit. General propensity rules for the transitions are also found and analyzed.

Protocol for optically pumping AlH+ to a pure quantum state

Three laser fields drive the population of AlH+ to a single hyperfine state.

Modular quantum computation in a trapped ion system

Modern computation relies crucially on modular architectures, breaking a complex algorithm into self-contained subroutines. A client can then call upon a remote server to implement parts of the computation independently via an application programming interface (API). Present APIs relay only classical information. Here we implement a quantum API that enables a client to estimate the absolute value of the trace of a server-provided unitary operation $$U$$ U . We demonstrate that the algorithm functions correctly irrespective of what unitary $$U$$ U the server implements or how the server specifically realizes $$U$$ U . Our experiment involves pioneering techniques to coherently swap qubits encoded within the motional states of a trapped $${}^{171}{{\rm{Yb}}}^{+}\,$$ 171 Yb + ion, controlled on its hyperfine state. This constitutes the first demonstration of modular computation in the quantum regime, providing a step towards scalable, parallelization of quantum computation.

EXACT SOLUTIONS TO THE SPIN-2 GROSS–PITAEVSKII EQUATIONS

We present several exact solutions to the coupled nonlinear Gross–Pitaevskii equations which describe the motion of the one-dimensional spin-2 Bose–Einstein condensates. The nonlinear density–density interactions are decoupled by making use of the properties of Jacobian elliptical functions. The distinct time factors in each hyperfine state implies a "Lamor" procession in these solutions. Furthermore, exact time-evolving solutions to the time-dependent Gross–Pitaevskii equations are constructed through the spin-rotational symmetry of the Hamiltonian. The spin-polarizations and density distributions in the spin-space are analyzed.