32,822 research outputs found
Exploring Vacuum Structure around Identity-Based Solutions
We explore the vacuum structure in bosonic open string field theory expanded
around an identity-based solution parameterized by . Analyzing the
expanded theory using level truncation approximation up to level 20, we find
that the theory has the tachyon vacuum solution for . We also find
that, at , there exists an unstable vacuum solution in the expanded
theory and the solution is expected to be the perturbative open string vacuum.
These results reasonably support the expectation that the identity-based
solution is a trivial pure gauge configuration for , but it can be
regarded as the tachyon vacuum solution at .Comment: 12 pages, 5 figures; new numerical data up to level (20,60) included;
Contribution to the proceedings of "Second International Conference on String
Field Theory and Related Aspects" (Steklov Mathematical Institute, Moscow,
Russia, April 12-19, 2009
Novel Quantum Criticality in CeRuSi near Absolute Zero Observed by Thermal Expansion and Magnetostriction
We report linear thermal expansion and magnetostriction measurements for
CeRuSi in magnetic fields up to 52.6 mT and at temperatures down to 1
mK. At high temperatures, this compound showed Landau-Fermi-liquid behavior:
The linear thermal expansion coefficient and the magnetostriction coefficient
were proportional to the temperature and magnetic field, respectively. In
contrast, a pronounced non-Fermi-liquid effect was found below 50 mK. The
negative contribution of thermal expansion and magnetostriction suggests the
existence of an additional quantum critical point
Ac Susceptibility and Static Magnetization Measurements of CeRuSi at Small Magnetic Fields and Ultra Low Temperatures
The magnetic properties of CeRuSi at microkelvin temperatures (down
to 170 K) and ultra small magnetic fields ( mT) are
investigated experimentally for the first time. The simultaneously measured ac
susceptibility and static magnetization show neither evidence of the magnetic
ordering, superconductivity down to the lowest temperatures nor conventional
Landau Fermi-Liquid behavior. The results imply the magnetic transition
temperature in undoped CeRuSi is very close to absolute 0 K. The
possibility for proximity of CeRuSi to the quantum critical point
without any doping is discussed.Comment: 4 pages, 3 figures; accepted for publication in Phys. Rev. B (Rapid
Communication) and scheduled issue on 1st of May 200
Factorization, reduction and embedding in integrable cellular automata
Factorized dynamics in soliton cellular automata with quantum group symmetry
is identified with a motion of particles and anti-particles exhibiting pair
creation and annihilation. An embedding scheme is presented showing that the
D^{(1)}_n-automaton contains, as certain subsectors, the box-ball systems and
all the other automata associated with the crystal bases of non-exceptional
affine Lie algebras. The results extend the earlier ones to higher
representations by a certain reduction and to a wider class of boundary
conditions.Comment: LaTeX2e, 20 page
Separation of colour degree of freedom from dynamics in a soliton cellular automaton
We present an algorithm to reduce the coloured box-ball system, a one
dimensional integrable cellular automaton described by motions of several
colour (kind) of balls, into a simpler monochrome system. This algorithm
extracts the colour degree of freedom of the automaton as a word which turns
out to be a conserved quantity of this dynamical system. It is based on the
theory of crystal basis and in particular on the tensor products of sl_n
crystals of symmetric and anti-symmetric tensor representations.Comment: 19 page
Exact Results for Tunneling Problems of Bogoliubov Excitations in the Critical Supercurrent State
We show the exact solution of Bogoliubov equations at zero-energy in the
critical supercurrent state for arbitrary shape of potential barrier. With use
of this solution, we prove the absence of perfect transmission of excitations
in the low-energy limit by giving the explicit expression of transmission
coefficient. The origin of disappearance of perfect transmission is the
emergence of zero-energy density fluctuation near the potential barrier.Comment: 6 pages, 3 figures; Proceedings of QFS200
Cellular Automata and Ultra-Discrete Painlev\'e Equations
Starting from integrable cellular automata we present a novel form of
Painlev\'e equations. These equations are discrete in both the independent
variable and the dependent one. We show that they capture the essence of the
behavior of the Painlev\'e equations organizing themselves into a coalescence
cascade and possessing special solutions. A necessary condition for the
integrability of cellular automata is also presented.Comment: 8 pages, plainTeX, 2 figure
3-point off-shell vertex in scalar QED in arbitrary gauge and dimension
We calculate the complete one-loop off-shell three-point scalar-photon vertex
in arbitrary gauge and dimension for Scalar Quantum Electrodynamics. Explicit
results are presented for the particular cases of dimensions 3 and 4 both for
massive and massless scalars. We then propose non-perturbative forms of this
vertex that coincide with the perturbative answer to order .Comment: Uses axodra
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