APIE TFAISeminaro vadovas: prof. habil. dr. Bronislovas KAULAKYS
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Seminaras "Stable two-dimensional semi-vortex solitons in spin-orbit-coupled self-attractive Bose-Einstein condensates in free space"
Antradienį, liepos 28 dieną 11 valandą 432 k. vyks Instituto Jungtinis teorinis seminaras:
"Stable two-dimensional semi-vortex solitons in spin-orbit-coupled self-attractive Bose-Einstein condensates in free space"
Pranešėjas
Boris A. Malomed
Department of Physical Electronics, School of Electrical Engineering,
Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
Pranešimo santrauka:
It is commonly known that two-dimensional mean-field models of optical and
matter waves with cubic self-attraction cannot produce stable solitons in
free space because of the occurrence of collapse in the same setting. By
means of numerical analysis and variational approximation, we demonstrate
that the two-component model of the Bose-Einstein condensate with the Rashba
spin-orbit coupling (SOC) and cubic attractive interactions gives rise to stable
solitary-vortex complexes of two types in the free space: semivortices (SVs,
with a vortex in one component and a fundamental soliton in the other), and
mixed modes (MMs, with topological charges 0 and ±1 mixed in both components).
The SVs and MMs realize the ground state of the system, provided that the
self-attraction in the two components is, respectively, stronger or weaker
than the cross attraction between them. The SVs and MMs which are not the
ground states are subject to a drift instability. The modes of both types
degenerate into unstable Townes solitons when their norms attain the
respective critical values, while there is no lower existence threshold for
the stable modes. Moving free-space stable solitons are also found in the
present non-Galilean-invariant system, up to a critical velocity. Collisions
between two moving solitons lead to their merger into a single one.
Additional results demonstrate similar solitons in the one-dimensional
and discrete two-dimensional versions of the SOC system (in those cases,
the stability is not an issue).
The work was recently published in:
H. Sakaguchi, B. Li, and B. A. Malomed, "Creation of two-dimensional composite
solitons in spin-orbit-coupled self-attractive Bose-Einstein condensates in free space", Phys. Rev. E 89, 032920 (2014);
H. Sakaguchi and B. A. Malomed, "Discrete and continuum composite solitons
in Bose-Einstein condensates with the Rashba spin-orbit coupling in one and two
dimensions", Phys. Rev. E 90, 062922 (2014).
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