Conditional dynamics induced by new configurations for Rydberg dipole-dipole interactions

Abstract

We suggest a novel way to use strong Rydberg dipole-dipole interactions in order to induce non-trivial conditional dynamics in individual-atom systems and mesoscopic ensembles. Contrary to previous works, we suggest to excite atoms into different Rydberg states, which results in a potentially richer dynamical behaviour. Specifically, we investigate systems of individual hydrogenlike atoms or mesoscopic ensembles excited into high-lying hydrogen-like s, p or d states and show how to perform three-qubit conditional dynamics on the information they contain through a proper use of dipole-dipole interaction induced energy shifts.

Quantum information with Rydberg atoms

“…A different type of gate which does not require strongly populating the Rydberg levels can be designed by using the interference of different multi-photon transition paths. The dipole-dipole interaction suppresses the amplitude of one of the paths (Brion et al, 2007c) which creates a conditional phase shift. This general idea can be used to implement a universal set of gates in a decoherence free subspace of logical qubits, each encoded in two physical qubits (Brion et al, 2007d).…”

Review of cold Rydberg atoms and their applications

“…For example, the three-qubit Toffoli gate computes t → c 1 c 2 ⊕ t for a given set of two control bits c 1 and c 2 and a target bit t. Thus, the target bit t is switched between 0 and 1 if both the control bits c 1 and c 2 are in state 1, and if either one of the control bits is in state 0, the target bit is unchanged. This gate has been designed with seven laser pulses, all of which are π pulses, in a three-Rydberg-atom system [78]. In this scheme, the three atoms are excited in different Rydberg energy levels, which enables the design of a more complex set of three-qubit gate operations.…”

Efficient Grover search with Rydberg blockade

“…Some calculations indicate that the dipole interaction shifts and hence the blockade mechanism are generally present also for more than two excited atoms [21], but special cases have been identified where two atoms block, while among three atoms resonant excitation of more than a single atom may be allowed [22]. We will assume that one can avoid the latter phenomenon by the appropriate choice of atomic systems, but we note that it may take a more detailed calculation to precisely assess the collective Rydberg interaction shifts within a collection of the state |s excited atoms and a single |r atom.…”