5 research outputs found
Superfluid to Mott insulator transition in one, two, and three dimensions
We have created one-, two-, and three-dimensional quantum gases and study the
superfluid to Mott insulator transition. Measurements of the transition using
Bragg spectroscopy show that the excitation spectra of the low-dimensional
superfluids differ significantly from the three-dimensional case
Maximal length of trapped one-dimensional Bose-Einstein condensates
I discuss a Bogoliubov inequality for obtaining a rigorous bound on the
maximal axial extension of inhomogeneous one-dimensional Bose-Einstein
condensates. An explicit upper limit for the aspect ratio of a strongly
elongated, harmonically trapped Thomas-Fermi condensate is derived.Comment: 6 pages; contributed paper for Quantum Fluids and Solids, Trento
2004, to appear in JLT
Strong dissipation inhibits losses and induces correlations in cold molecular gases
Atomic quantum gases in the strong-correlation regime offer unique
possibilities to explore a variety of many-body quantum phenomena. Reaching
this regime has usually required both strong elastic and weak inelastic
interactions, as the latter produce losses. We show that strong inelastic
collisions can actually inhibit particle losses and drive a system into a
strongly-correlated regime. Studying the dynamics of ultracold molecules in an
optical lattice confined to one dimension, we show that the particle loss rate
is reduced by a factor of 10. Adding a lattice along the one dimension
increases the reduction to a factor of 2000. Our results open up the
possibility to observe exotic quantum many-body phenomena with systems that
suffer from strong inelastic collisions
Observation of Correlated Particle-Hole Pairs and String Order in Low-Dimensional Mott Insulators
Quantum phases of matter are characterized by the underlying correlations of
the many-body system. Although this is typically captured by a local order
parameter, it has been shown that a broad class of many-body systems possesses
a hidden non-local order. In the case of bosonic Mott insulators, the ground
state properties are governed by quantum fluctuations in the form of correlated
particle-hole pairs that lead to the emergence of a non-local string order in
one dimension. Using high-resolution imaging of low-dimensional quantum gases
in an optical lattice, we directly detect these pairs with single-site and
single-particle sensitivity and observe string order in the one-dimensional
case.Comment: 9 pages, 7 figure