Emission of (Giant) atoms under an electric field

Giant atoms allow for two major effects: engineered coupling to field modes and time-delayed non-Markovian dynamics. Here, we discuss two novel paradigms for these phenomena, both arising in a photonic lattice (implemented through a 1D or 2D coupled-cavity array) with an applied synthetic electric field. We first consider a 2D lattice implementing photonic graphene with an open gap. We propose that, by relying on giant atoms, one can combine ideas from valleytronics [1] with quantum optics to produce chiral light orthogonal to the electric field direction, without the need to break time-reversal symmetry of the lattice [2]. We then consider a simple 1D array with an applied electric field, where Bloch oscillations are known to occur. We show that an atom emitting into such a lattice generally undergoes non-Markovian dynamics. In a suitable regime, this resembles the dynamics of an atom in a long, multi-mode, perfect cavity (despite no true mirrors being present), with the photon time delay embodied by the Bloch oscillations period [3]. References [1] J. R. Schaibley et al., Valleytronics in 2D materials, Nature Reviews Materials 1, 1 (2016). [2] M. A. Pinto, G. L. Sferrazza, D. De Bernardis, F. Ciccarello, in preparation (2025). [3] M.A. Pinto et al. Non-Markovian dynamics of a qubit due to accelerated light in a lattice. arXiv preprint arXiv:2503.19021 (2025)