Spin- and momentum-correlated atom pairs mediated by photon exchange

Abstract

Pairs of correlated particles are at the core of complex many-body phenomena and their control is essential for quantum technologies. Engineering pairs that are simultaneously correlated in their external and internal degrees of freedom is a major challenge. In this work, we experimentally demonstrate a mechanism for generating pairs of atoms in well-defined spin and momentum modes. This mechanism couples atoms from a degenerate Bose gas via a superradiant photon-exchange process mediated by the vacuum mode of an optical cavity. The scheme is independent of collisional interactions, fast and tunable. We observe a collectively enhanced production of pairs, characterize their statistics, and measure inter-spin correlations in momentum space. Our observation of coherent many-body oscillations involving well-defined momentum modes offers promising prospects for quantum-enhanced interferometry using entangled matter waves.

Generating Multiparticle Entangled States by Self-Organization of Driven Ultracold Atoms

“…For higher N calculations reachable with the H ad model, the ξ 2 m again decreases for decreasing the decay rate κ at fixed detunings Δc , Δ0 c , and η eff =η c [see Fig. 4(a)], which is a consequence of increasing the ratio −g cav =γ ¼ 2j Δ0 c j=κ, leading toward coherent cavity dynamics, similarly to the single-mode cavity case [54,105]. The parameters Δ0 c =κ and η eff =η c completely determine the open system dynamics for H ad with N atoms.…”

“…2(c). The hJ 2 eff i initially rises, and then starts to approximately periodically oscillate in time, with the characteristic timescale τ ∼ 2π=ðNg mod Þ for H B and τ [105]. For H B , the atoms scatter in and out of the transverse sidebands by absorbing and emitting energy quanta from and to the driving magnetic field, while for H ad one observes sloshing dynamics (see below).…”

Quantum enhanced SU(1,1) matter-wave interferometry in a ring cavity

“…The earlier works on the quantum aspects of ultracold atomcavity interaction have concentrated on studying steady state quantum correlations between light and atoms [10,[28][29][30][31][32][33]. Recently, the generation of correlated atomic pairs via cavity lightmediated interaction and self-organization, has also come into focus [34][35][36], inspired by the earlier work on photon quantum correlations in optical parametric amplifiers and self-organized optical structures in nonlinear crystals [37][38][39][40][41][42]. These recent works shift the attention from light-atom entanglement, which was studied in [10,[28][29][30][31][32][33], towards light-mediated atom-atom entanglement generation in a cavity.…”

“…The importance of quantum entangled states in quantum technologies lies in their ability to speed up a number of computational [43] and metrological tasks [44,45]. Regarding the latter, quantum enhanced measurement schemes with internal atomic degrees of freedom [34,[46][47][48][49][50][51][52][53][54][55][56], and also the motional ones [35,[57][58][59][60][61], have been explored recently.…”

“…A similar setup has been experimentally implemented in [24]. Contrary to the similar recently utilized mechanisms for entanglement generation using atoms with multilevel transitions [34,35], the situation studied here relies on atoms and light interacting via a two-level optical transition.…”