4 research outputs found
Material-barrier Tunneling in One-dimensional Few-boson Mixtures
We study the quantum dynamics of strongly interacting few-boson mixtures in
one-dimensional traps. If one species is strongly localized compared to the
other (e.g., much heavier), it can serve as an effective potential barrier for
that mobile component. Near the limit of infinite localization, we map this to
a system of identical bosons in a double well. For realistic localization, the
backaction of the light species on the "barrier" atoms is explained--to lowest
order--in terms of an induced attraction between these. Even in equilibrium,
this may outweigh the bare intra-species interaction, leading to unexpected
correlated states. Remarkably, the backaction drastically affects the
inter-species dynamics, such as the tunneling of an attractively bound pair of
fermionized atoms.Comment: 10 pages, 3 figure
Inter-species Tunneling in One-dimensional Bose Mixtures
We study the ground-state properties and quantum dynamics of few-boson
mixtures with strong inter-species repulsion in one-dimensional traps. If one
species localizes at the center, e.g., due to a very large mass compared to the
other component, it represents an effective barrier for the latter and the
system can be mapped onto identical bosons in a double well. For weaker
localization, the barrier atoms begin to respond to the light component,
leading to an induced attraction between the mobile atoms that may even
outweigh their bare intra-species repulsion. To explain the resulting effects,
we derive an effective Hubbard model for the lighter species accounting for the
backaction of the barrier in correction terms to the lattice parameters. Also
the tunneling is drastically affected: Varying the degree of localization of
the "barrier" atoms, the dynamics of intrinsically noninteracting bosons can
change from Rabi oscillations to effective pair tunneling. For identical
fermions (or fermionized bosons) this leads to the tunneling of attractively
bound pairs.Comment: 13 pages, 11 figures; v2 reflects major revisio
Optomechanics assisted with a qubit: From dissipative state preparation to many-body physics
We propose and analyze nonlinear optomechanical protocols that can be
implemented by adding a single atom to an optomechanical cavity. In particular,
we show how to engineer the environment in order to dissipatively prepare the
mechanical oscillator in a superposition of Fock states with fidelity close to
one. Furthermore, we discuss how a single atom in a cavity with several
mechanical oscillators can be exploited to realize nonlinear many-body physics
by stroboscopically driving the mechanical oscillators. We show how to prepare
non-classical many-body states by either applying coherent protocols or
engineering dissipation. The analysis of the protocols is carried out using a
perturbation theory for degenerate Liouvillians and numerical tools. Our
results apply to other systems where a qubit is coupled to a mechanical
oscillator via a bosonic mode, e.g., in cavity quantum electromechanics
Master equation approach to optomechanics with arbitrary dielectrics
We present a master equation describing the interaction of light with
dielectric objects of arbitrary sizes and shapes. The quantum motion of the
object, the quantum nature of light, as well as scattering processes to all
orders in perturbation theory are taken into account. This formalism extends
the standard master equation approach to the case where interactions among
different modes of the environment are considered. It yields a genuine quantum
description, including a renormalization of the couplings and decoherence
terms. We apply this approach to analyze cavity cooling of the center-of-mass
mode of large spheres. Furthermore, we derive an expression for the
steady-state phonon numbers without relying on resolved-sideband or bad-cavity
approximations.Comment: 17 pages, 5 figure