Coherent Excitation of Rydberg States

Abstract

In neutral Rydberg atom systems a host of quantum mechanical phenomena have been investigated, several of which are reviewed in Sect. 1.2. Quantum mechanical phenomena are observed most easily in isolated systems with strong coupling between only a few levels. With our understanding of Rydberg ion trap effects (see Chap. 6) we isolate a single Rydberg level and couple it with two other atomic levels using light fields; we then investigate the quantum-mechanical phenomena which appear. While coupling between two levels gives rise to Rabi oscillations, coupling between the levels of a three-level system results in a range of phenomena [1], including the Autler–Townes effect (reported in Sect. 7.2), electromagnetically-induced transparency (EIT), two-photon Rabi oscillations (Sect. 7.3), as well as stimulated Raman adiabatic passage (STIRAP) (Sect. 7.4). Using STIRAP for coherent Rydberg excitation and deexcitation we measure the Rydberg state lifetime (Sect. 7.4.2) and carry out a single-qubit Rydberg phase gate (Sect. 7.4.3). This gate demonstrates the basic workings of a Rydberg ion quantum computer. Many of the results in this chapter are published in Physical Review Letters [2] or else are under review—a working manuscript is available at [3]. Before describing the results, the three-level system is introduced in Sect. 7.1.