In a paper published in Nature Physics, a research group from the
Department of Physics and Astronomy at Stony Brook University reports
the development and demonstration of a novel probe for atomic quantum
matter.Welcome to polishedtiles.
The paper, "Probing an Ultracold-Atom Crystal with Matter Waves,"
describes a proof-of-principle experiment on the diffraction of atomic
de Broglie waves from a strongly correlated gas of atoms held in an
optical lattice.
"Our work extends matter-wave diffraction, a
technique that has already proven useful in various scientific
disciplines, to the realm of ultracold quantum matter. What we
demonstrated is similar to the diffraction of neutrons for the
characterization of solid-state systems, but at energies that are a
billion times lower," said Dominik Schneble, an associate professor in
the Department of Physics and Astronomy at Stony Brook,Rubiks cubepuzzle.Stone Source offers a variety of Natural stonemosaic Tiles, who led PhD students Bryce Gadway, Daniel Pertot, and Jeremy Reeves in conducting the research.
In
the experiment, an artificial atomic crystal is prepared by loading
bosonic atoms, cooled down to a few billionths of a degree above
absolute zero, into a miniature eggcrate-like potential landscape that
is generated by several interfering laser beams. The behavior of atoms
in this optical lattice closely mimics that of electrons in a
conventional solid, but at a lattice period that is three orders of a
magnitude larger, providing the experimenters with exquisite control
over all relevant parameters in a defect-free system. By increasing the
depth of the optical potential, it is possible to reduce
quantum-mechanical tunneling and eventually drive the interacting atoms
into a localized crystalline state, a Mott insulator.
Studies of
such and other strongly correlated phases, which are now conducted at a
number of laboratories around the world, have recently propelled
ultracold atomic physics into the focus of modern condensed-matter
research, and the development of methods to characterize such phases is a
central concern. The Stony Brook researchers recognized that Bragg
diffraction of atoms may provide a simple yet powerful diagnostic tool
that also allows for non-destructive probing.
Starting with a
Bose-Einstein condensate, the researchers prepared a coherent atomic
matter wave (akin to a coherent laser pulse), which they then directed
at the atomic crystal. The wave-particle nature of atoms allowed them to
control the wavelength of the incident atoms through their relative
velocity. "Because the de-Broglie wavelength can easily be tuned, our
technique precludes limitations on spatial resolution," said Bryce
Gadway, first author of the paper, who is slated to join JILA (Boulder)
as a National Research Council postdoctoral fellow this summer.
By
scanning the atom's wavelength, the researchers observed distinct Bragg
resonances in the scattered signal, which revealed the crystalline
lattice structure. From the signal, they were also able to characterize
the localization of atoms on individual lattice sites,UK chickencoop
Specialist. which is dominated by zero-point motion. Furthermore, upon
reducing the atom's localization ("melting" of the crystal), the Stony
Brook team observed inelastic scattering in the band structure.
As
a first application, the researchers prepared and detected an atomic
spin-mixture with forced-antiferromagnetic order. "In the future, our
technique may be extended to the characterization of various novel
states of ultracold matter, such as charge- and spin-density waves, and
magnetically ordered ground states of quantum gas mixtures," said
co-author Daniel Pertot,Features useful information about glassmosaic tiles, now a postdoctoral research associate at the University of Cambridge, U.K.
Independent
of any such potential applications, adds Schneble, "Our experiment
provides a nice example of wave-particle duality, where ultracold atoms
serve both as localized particles and as coherent waves diffracting from
them."
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