3,325 research outputs found
Force measurements of a superconducting-film actuator for a cryogenic interferometric gravitational-wave detector
We measured forces applied by an actuator with a YBCO film at near 77 K for
the Large-scale Cryogenic Gravitational-wave Telescope (LCGT) project. An
actuator consisting of both a YBCO film of 1.6 micrometers thickness and 0.81
square centimeters area and a solenoid coil exerted a force of up to 0.2 mN on
a test mass. The presented actuator system can be used to displace the mirror
of LCGT for fringe lock of the interferometer.Comment: 9 pages, 3 figure
Fermionic One-Loop Corrections to Soliton Energies in 1+1 Dimensions
We demonstrate an unambiguous and robust method for computing fermionic
corrections to the energies of classical background field configurations. We
consider the particular case of a sequence of background field configurations
that interpolates continuously between the trivial vacuum and a widely
separated soliton/antisoliton pair in 1+1 dimensions. Working in the continuum,
we use phase shifts, the Born approximation, and Levinson's theorem to avoid
ambiguities of renormalization procedure and boundary conditions. We carry out
the calculation analytically at both ends of the interpolation and numerically
in between, and show how the relevant physical quantities vary continuously. In
the process, we elucidate properties of the fermionic phase shifts and zero
modes.Comment: 12 pages, 4 figures, uses BoxedEPS;v2: fixed numerical error in
figure dat
Energy, Central Charge, and the BPS Bound for 1+1 Dimensional Supersymmetric Solitons
We consider one-loop quantum corrections to soliton energies and central
charges in the supersymmetric and sine-Gordon models in 1+1
dimensions. In both models, we unambiguously calculate the correction to the
energy in a simple renormalization scheme and obtain ,
in agreement with previous results. Furthermore, we show that there is an
identical correction to the central charge, so that the BPS bound remains
saturated in the one-loop approximation. We extend these results to arbitrary
1+1 dimensional supersymmetric theories.Comment: 15 pages, RevTeX; v2: generalized energy result, added minor
clarifications, and fixed typos; v3: more minor clarifications and
corrections; v4: fixed factor of 2 in eq. (25); v5: fixed minor error in eq.
(55
Partial and macroscopic phase coherences in underdoped BiSrCaCuO thin film
A combined study with use of time-domain pump-probe spectroscopy and
time-domain terahertz transmission spectroscopy have been carried out on an
underdoped BiSrCaCuO thin film. It was observed that
the low energy multi-excitation states were decomposed into superconducting gap
and pseudogap. The pseudogap locally opens below K
simultaneously with the appearance of the high-frequency partial pairs around
1.3 THz. With decreasing temperature, the number of the local domains with the
partial phase coherence increased and saturated near 100 K, and the macroscopic
superconductivity appeared below 76 K through the superconductivity fluctuation
state below 100 K. These experimental results indicate that the pseudogap makes
an important role for realization of the superconductivity as a precursor to
switch from the partial to the macroscopic phase coherence.Comment: Revtex4, 4 pages, 4 figure
Geometrically Induced Gauge Structure on Manifolds Embedded in a Higher Dimensional Space
We explain in a context different from that of Maraner the formalism for
describing motion of a particle, under the influence of a confining potential,
in a neighbourhood of an n-dimensional curved manifold M^n embedded in a
p-dimensional Euclidean space R^p with p >= n+2. The effective Hamiltonian on
M^n has a (generally non-Abelian) gauge structure determined by geometry of
M^n. Such a gauge term is defined in terms of the vectors normal to M^n, and
its connection is called the N-connection. In order to see the global effect of
this type of connections, the case of M^1 embedded in R^3 is examined, where
the relation of an integral of the gauge potential of the N-connection (i.e.,
the torsion) along a path in M^1 to the Berry's phase is given through Gauss
mapping of the vector tangent to M^1. Through the same mapping in the case of
M^1 embedded in R^p, where the normal and the tangent quantities are exchanged,
the relation of the N-connection to the induced gauge potential on the
(p-1)-dimensional sphere S^{p-1} (p >= 3) found by Ohnuki and Kitakado is
concretely established. Further, this latter which has the monopole-like
structure is also proved to be gauge-equivalent to the spin-connection of
S^{p-1}. Finally, by extending formally the fundamental equations for M^n to
infinite dimensional case, the present formalism is applied to the field theory
that admits a soliton solution. The resultant expression is in some respects
different from that of Gervais and Jevicki.Comment: 52 pages, PHYZZX. To be published in Int. J. Mod. Phys.
Stability of control system in handling of a flexible object by rigid arm robots
科研費報告書収録論文(課題番号:07455416・基盤研究(B)(2)・H7~H9/研究代表者:内山, 勝/フレキシブル双腕ロボットの協調制御に関する研究
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