111 research outputs found
Rosen-Zener interferometry with Ultracold Atoms
We propose a time-domain "interferometer" based on ultracold Bose atoms
loaded on a double well potential. By the adiabatic Rosen-Zener process, the
barrier between two wells is ramped down slowly, held for a while, then ramped
back. Starting with a coherent state of double well system, the final
occupations on one well show interesting interference fringes in the
time-domain. The fringe pattern is sensitive to the initial state, the
interatomic interaction, and the external forces such as gravity which can
change the shape of the double well. In this sense, this interferometric scheme
has the potentials for precision measurements with ultracold atoms. The
underlying mechanism is revealed and possible applications are discussed.Comment: 4 pages, 5 figure
Topological inverse band theory in waveguide quantum electrodynamics
Topological phases play a crucial role in the fundamental physics of
light-matter interaction and emerging applications of quantum technologies.
However, the topological band theory of waveguide QED systems is known to break
down, because the energy bands become disconnected. Here, we introduce a
concept of the inverse energy band and explore analytically topological
scattering in a waveguide with an array of quantum emitters. We uncover a rich
structure of topological phase transitions, symmetric scale-free localization,
completely flat bands, and the corresponding dark Wannier states. Although
bulk-edge correspondence is partially broken because of radiative decay, we
prove analytically that the scale-free localized states are distributed in a
single inverse energy band in the topological phase and in two inverse bands in
the trivial phase. Surprisingly, the winding number of the scattering textures
depends on both the topological phase of inverse subradiant band and the
odevity of the cell number. Our work uncovers the field of the topological
inverse bands, and it brings a novel vision to topological phases in
light-matter interactions.Comment: Accepted for publication in Phys. Rev. Let
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