11 research outputs found
Controlled long-range interactions between Rydberg atoms and ions
We theoretically investigate trapped ions interacting with atoms that are
coupled to Rydberg states. The strong polarizabilities of the Rydberg levels
increases the interaction strength between atoms and ions by many orders of
magnitude, as compared to the case of ground state atoms, and may be mediated
over micrometers. We calculate that such interactions can be used to generate
entanglement between an atom and the motion or internal state of an ion.
Furthermore, the ion could be used as a bus for mediating spin-spin
interactions between atomic spins in analogy to much employed techniques in ion
trap quantum simulation. The proposed scheme comes with attractive features as
it maps the benefits of the trapped ion quantum system onto the atomic one
without obviously impeding its intrinsic scalability. No ground state cooling
of the ion or atom is required and the setup allows for full dynamical control.
Moreover, the scheme is to a large extent immune to the micromotion of the ion.
Our findings are of interest for developing hybrid quantum information
platforms and for implementing quantum simulations of solid state physics.Comment: 20 pages including appendices, 6 figure
Designing Frustrated Quantum Magnets with Laser-Dressed Rydberg Atoms
We show how a broad class of lattice spin-1/2 models with angular- and
distance-dependent couplings can be realized with cold alkali atoms stored in
optical or magnetic trap arrays. The effective spin-1/2 is represented by a
pair of atomic ground states, and spin-spin interactions are obtained by
admixing van der Waals interactions between fine-structure split Rydberg states
with laser light. The strengths of the diagonal spin interactions as well as
the "flip-flop", and "flip-flip" and "flop-flop" interactions can be tuned by
exploiting quantum interference, thus realizing different spin symmetries. The
resulting energy scales of interactions compare well with typical temperatures
and decoherence time-scales, making the exploration of exotic forms of quantum
magnetism, including emergent gauge theories and compass models, accessible
within state-of-the-art experiments.Comment: 11 pages, 7 figure
Dynamical preparation of laser-excited anisotropic Rydberg crystals in 2D optical lattices
We describe the dynamical preparation of anisotropic crystalline phases
obtained by laser-exciting ultracold Alkali atoms to Rydberg p-states where
they interact via anisotropic van der Waals interactions. We develop a time-
dependent variational mean field ansatz to model large, but finite
two-dimensional systems in experimentally accessible parameter regimes, and we
present numerical simulations to illustrate the dynamical formation of
anisotropic Rydberg crystals.Comment: 19 pages, 9 figure
Quantum Spin Ice and dimer models with Rydberg atoms
Quantum spin ice represents a paradigmatic example on how the physics of
frustrated magnets is related to gauge theories. In the present work we address
the problem of approximately realizing quantum spin ice in two dimensions with
cold atoms in optical lattices. The relevant interactions are obtained by
weakly admixing van der Waals interactions between laser admixed Rydberg states
to the atomic ground state atoms, exploiting the strong angular dependence of
interactions between Rydberg p-states together with the possibility of
designing step-like potentials. This allows us to implement Abelian gauge
theories in a series of geometries, which could be demonstrated within state of
the art atomic Rydberg experiments. We numerically analyze the family of
resulting microscopic Hamiltonians and find that they exhibit both classical
and quantum order by disorder, the latter yielding a quantum plaquette valence
bond solid. We also present strategies to implement Abelian gauge theories
using both s- and p-Rydberg states in exotic geometries, e.g. on a 4-8 lattice.Comment: 26 pages, 16 figure
Discrete time crystal in globally driven interacting quantum systems without disorder
Summarization: Time crystals in periodically driven systems have initially been studied assuming either the ability to quench the Hamiltonian between different many-body regimes, the presence of disorder or long-range interactions. Here we propose the simplest scheme to observe discrete time crystal dynamics in a one-dimensional driven quantum system of the Ising type with short-range interactions and no disorder. The system is subject only to a periodic kick by a global magnetic field, and no extra Hamiltonian quenching is performed. We analyze the emerging time crystal stabilizing mechanisms via extensive numerics as well as using an analytic approach based on an off-resonant transition model. Due to the simplicity of the driven Ising model, our proposal can be implemented with current experimental platforms including trapped ions, Rydberg atoms, and superconducting circuits.Παρουσιάστηκε στο: Physical Review