Description
Dynamic transients are a natural ingredient of out-of-equilibrium quantum systems. One paradigmatic example is Dicke superradiance, describing the collectively enhanced population inversion of an ensemble of two-level atoms coupled to a single mode of the electromagnetic field.
Here, we present a new approach exploiting superradiance to engineer dynamical tunneling in a synthetic lattice geometry. Our experimental implementation is based on a spinor Bose-Einstein condensate (BEC), which is coupled to a single mode of an ultrahigh-finesse optical cavity [1]. Transverse laser fields induce cavity-assisted Raman transitions between discrete momentum modes of two spin levels, which we interpret as photon-assisted tunnelling in a momentum-space lattice. In particular, the tunnelling rate evolves dynamically with the emergent cavity field. By monitoring the cavity leakage, we gain real-time access to the lattice currents and benchmark their collective behaviour [2].
In a series of recent experiments, we engineer an atomic mode parametric amplifier induced by virtual cavity photons. The spinor BEC is initialized in the |F = 1, mF = 0⟩ Zeeman sublevel (pump mode), and correlated pairs of atoms in |mF = ±1⟩ (signal and idler modes) are created by four-photon processes, which involve scattering of virtual cavity photons in a far-detuned regime. The pair production is highly non-linear, as evidenced by its scaling with atom number. Moreover, the spin pairs are ejected out of the BEC with opposite relative momenta, in resemblance parametric four-wave mixing. While similar to collisional spin-mixing dynamics [3], the timescales of this process (~10 μs) are significantly faster, providing prospects rapid entanglement production in cold atom experiments.
References
[1] F. Ferri, R. Rosa-Medina, F. Finger, N. Dogra, M. Soriente, O. Zilberberg, T. Donner, T. Esslinger,
(2021). Emerging dissipative phases in a superradiant quantum gas with tunable decay. Physical Review X, 11(4), 041046.
[2] R. Rosa-Medina, F. Ferri, F. Finger, N. Dogra, K. Kroeger, R. Lin, R. Chitra, T. Donner,
T. Esslinger, (2022). Observing dynamical currents in a non-Hermitian momentum lattice. Physical Review Letters, 128(14), 143602.
[3] L. Pezze, A. Smerzi, M.K. Oberthaler, R. Schmied, P.Treutlein, (2018). Quantum metrology with nonclassical states of atomic ensembles. Reviews of Modern Physics, 90(3), 035005.
| Presenter name | Rodrigo Rosa-Medina |
|---|---|
| How will you attend ICAP-27? | I am planning on in-person attendance |
