602 research outputs found
Transition from Tonks-Girardeau gas to super-Tonks-Girardeau gas as an exact many-body dynamics problem
We investigate transition of a one-dimensional interacting Bose gas from a
strongly repulsive regime to a strongly attractive regime, where a stable
highly excited state known as the super Tonks-Girardeau gas was experimentally
realized very recently. By solving exact dynamics of the integrable
Lieb-Liniger Bose gas, we demonstrate that such an excited gas state can be a
very stable dynamic state. Furthermore we calculate the breathing mode of the
super Tonks-Girardeau gas which is found to be in good agreement with
experimental observation. Our results show that the highly excited super
Tonks-Girardeau gas phase can be well understood from the fundamental theory of
the solvable Bose gas.Comment: 4 pages, 4 figures, version to appear in Phys. Rev. A as a Rapid
Communicatio
Construction of spirocarbocycles via gold-catalyzed intramolecular dearomatization of naphthols.
A highly efficient, gold-catalyzed intramolecular dearomatization reaction of naphthols via 5-endo-dig cyclization is described. This facile and direct approach furnishes spirocarbocycles in excellent yields under mild conditions
Realization of effective super Tonks-Girardeau gases via strongly attractive one-dimensional Fermi gases
A significant feature of the one-dimensional super Tonks-Girardeau gas is its
metastable gas-like state with a stronger Fermi-like pressure than for free
fermions which prevents a collapse of atoms. This naturally suggests a way to
search for such strongly correlated behaviour in systems of interacting
fermions in one dimension. We thus show that the strongly attractive Fermi gas
without polarization can be effectively described by a super Tonks-Girardeau
gas composed of bosonic Fermi pairs with attractive pair-pair interaction. A
natural description of such super Tonks-Girardeau gases is provided by Haldane
generalized exclusion statistics. In particular, we find that they are
equivalent to ideal particles obeying more exclusive statistics than
Fermi-Dirac statistics.Comment: 4 pages, 2 figure
Theoretical study of small signal modulation behavior of Fabry-Perot Germanium-on-Silicon lasers
This work investigated the small signal performance of Fabry-Perot Ge-on-Si
lasers by modeling and simulations. The 3dB bandwidth dependence on the
structure parameters such as poly-Si cladding thickness, Ge cavity width and
thickness, and minority carrier lifetime were studied. A 3dB bandwidth of 33.94
GHz at a biasing current of 270.5 mA is predicted after Ge laser structure
optimization with a defect limited carrier lifetime of 1 ns
Accurate FCS Model Predictive Current Control Technique for Surface-mounted PMSMs at Low Control Frequency
On the security of a certificateless aggregate signature scheme
Aggregate signature can combinensignatures on nmessages fromnusers into a single short signature, and the resulting signature can convince the verifier that thenusers indeed signed
the ncorresponding messages. This feature makes aggregate signature very useful especially in environments with low bandwidth communication, low storage and low computability since it
greatly reduces the total signature length and verification cost. Recently, Xiong et al. presented an efficient certificateless aggregate signature scheme. They proved that their scheme is secure in a strengthened security model, where the “malicious-but-passive” KGC attack was considered. In this paper, we show that Xiong et al.’s certificateless aggregate signature scheme is not secure
even in a weaker security model called “honest-but-curious” KGC attack model
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